How to File a PCT International Application from India (2026 Guide)

An applicant resident in India can file a PCT international patent application in two ways: by claiming priority from an Indian patent filing within 12 months, or by filing a direct PCT application after obtaining a Foreign Filing Licence under Section 39 of the Patents Act 1970. The Patent Cooperation Treaty allows a single international filing that preserves patent rights in more than 150 countries while deferring national filing decisions for up to 30 or 31 months from the priority date.

However, there is a compliance gate that most guides overlook entirely. Before a single document is submitted to any receiving office, every person resident in India must comply with Section 39 of the Patents Act 1970. Getting this wrong carries criminal liability under Section 118. Getting it right takes less than a page of paperwork, if you know it exists.

This guide walks through the entire outbound PCT filing process from India, including Section 39 compliance, receiving office choice, ISA selection, fee calculation, and the international phase timeline. By the end, you will know which receiving office to use, how to choose your International Searching Authority, what the fees actually are for applicants in 2026, and what happens after you file.

This article covers the international filing phase. For what happens after your PCT application enters India as a designated country, see our guide on PCT national phase entry in India.

1. What Is a PCT Application and How Does It Work?

A PCT application is a single international patent application filed under the Patent Cooperation Treaty, an international agreement administered by WIPO (the World Intellectual Property Organization). India has been a PCT member since 7 December 1998.

Filing a PCT international application does not give you a global patent – no such thing exists. What it gives you is a single international filing date recognised by all 157 PCT member countries, combined with up to 30 or 31 months from your priority date to decide in which specific countries you want to pursue national patent protection. You file once now; you decide your final country list later.

This deferral is the core commercial value of the PCT for Indian startups. Those 30 months give you time to raise funding, test markets, watch how competitors respond, and avoid spending money on national phase filings in countries where you ultimately decide the opportunity does not justify the cost.

During the international phase, WIPO arranges an international search – a prior art search conducted by a specialised patent office called the International Searching Authority (ISA). This search produces an International Search Report and a Written Opinion on patentability. This report travels ahead of you into every national phase, giving foreign patent offices a head start and potentially reducing examination time and cost in each country.

What the PCT does not do: it does not examine your application, it does not grant a patent, and it does not guarantee protection anywhere. The grant decision belongs entirely to each national or regional patent office after you enter their national phase.

2. The two ways to file a PCT application from India

Before filing, you need to know which of two routes applies to your situation – because this determines your timeline, your priority date, and how Section 39 compliance works.

Type A: PCT Filing With Indian Priority (Most Common)

If you have already filed a patent application in India – whether a provisional specification or a complete specification – you have up to 12 months from that Indian filing date to file your PCT application claiming priority from it. The Indian application becomes your priority document. All subsequent national phase deadlines – the 30-month or 31-month windows – run from that original Indian filing date, not from the PCT filing date itself.

Example: You file a provisional application in India on 1 April 2025. Your PCT filing deadline is 1 April 2026 (12 months later). Your national phase deadline in most countries is 1 October 2027 – 30 months from 1 April 2025, your priority date.

Type B: Direct PCT Filing With No Indian Priority

You can also file a PCT international application as your very first filing, with no prior Indian patent application. In this case, the PCT international filing date itself becomes the priority date. This route is less common for Indian startups but is used when speed to international filing matters more than establishing Indian priority first, or when the commercial strategy does not require Indian protection at all.

If you take this route, there is no six-week waiting period to rely on – so you must obtain a Foreign Filing Licence before filing internationally. The full procedure is explained in the next section, and we cover the Form 25 process in detail in our guide on obtaining a Foreign Filing Licence in India.

3. Section 39 of the Patents Act 1970: The compliance gate every Indian applicant must clear

Before filing a PCT international application, every Indian resident must comply with Section 39 of the Patents Act 1970. This is not optional and cannot be bypassed by routing the application through the Indian Patent Office – the Delhi High Court confirmed in Puneet Kaushik & Anr. v. Union of India that a PCT application constitutes a foreign application for the purposes of Section 39, even when filed through the Indian Patent Office as receiving office.

Section 39 exists to ensure that inventions originating in India – particularly those relevant to defence or national security – are reviewed by the Controller of Patents before being disclosed internationally. It applies to any person resident in India.

Route A: File in India first, then wait six weeks

This is the most common and straightforward path. If you have already filed a patent application in India for the same invention, and at least six weeks have elapsed from that Indian filing date without the Controller issuing a secrecy direction, you are free to file your PCT application without any further permission. No Form 25, no fee, no waiting for an approval letter.

This is why Type A is the standard route for Indian startups or companies. By the time most applicants are ready to file their PCT – typically three to twelve months after the Indian filing – the six-week window has long passed, and Section 39 is automatically satisfied.

Route B: Apply for a Foreign Filing Licence on Form 25

If you want to file your PCT application before six weeks have elapsed from your Indian application date, or if you are filing a direct PCT with no Indian application (Type B above), you must apply for a Foreign Filing Licence on Form 25 before filing internationally.

The application is submitted to the Indian Patent Office and must include details of the invention, the countries where you intend to file, and the reasons for the application. Under Rule 71 of the Patents Rules 2003, the Controller must respond within 21 days. For inventions relating to defence or atomic energy, the 21-day clock starts only from the date the Central Government gives its consent – which can take longer.

For the full Form 25 procedure – what the application must contain, how to submit it, and what to do while waiting for the response – see our detailed guide on obtaining a Foreign Filing Licence in India.

What happens if you skip Section 39?

4. RO/IN vs RO/IB: Which receiving office should you use?

RO/IN (the Indian Patent Office) is the right choice for the vast majority of Indian startups. If you have an Indian priority application and have already satisfied Section 39, file through RO/IN: you pay in INR, your priority document is handled automatically at no extra cost, and the process integrates naturally with your existing Indian prosecution file.

A receiving office is the office where you submit your PCT application. It performs the initial formality check, assigns your international filing date, collects the fees, and forwards the application to the ISA and to the WIPO International Bureau. Your choice of receiving office does not restrict which countries you can designate or which ISA you can use.

Indian applicants have two options: RO/IN or RO/IB (the International Bureau of WIPO in Geneva). The table below sets out the key differences:

RO/IB is relevant when you are filing a direct PCT with no Indian priority (Type B), when you have co-applicants from multiple countries, or when your agents already work extensively with WIPO’s ePCT system. One important practical difference: RO/IB accepts fees only in CHF, USD or EUR – INR is not accepted – so you will need to arrange an international transfer. And because the IB does not verify Section 39 compliance, you bear sole legal responsibility for ensuring the six-week wait or FFL is in place before you file.

5. What goes into the PCT application?

A PCT application has five mandatory components. Your patent agent will prepare all five – your role as the founder or inventor is to provide a clear invention disclosure and confirm the inventor details. Here is what each component is and why it matters:

1. The request form (PCT/RO/101): The formal application form, prepared electronically through ePCT. It names the applicants, inventors, and chosen ISA, records the priority claim, and designates all PCT member states for protection (all states are auto-designated unless you opt out).
2. The description: A full written disclosure explaining how the invention works and how it is made or used. It must be detailed enough for a person skilled in the relevant technical field to reproduce the invention without undue experimentation.
3. The claims: The numbered statements that define the legal scope of protection you are seeking. These are what the ISA searches against and what each national patent office examines in the national phase – the claims are the most strategically critical part of the application.
4. The abstract: A brief technical summary of the invention, not exceeding 150 words. It is used for search and publication purposes but does not legally define the scope of protection.
5. Drawings (where required): Required when the nature of the invention makes drawings necessary to understand it. Most mechanical, electrical, and software-related inventions require drawings. Colour or greyscale drawings are accepted at RO/IN and transmitted to the IB, but a black-ink version must also be submitted in response to Form PCT/RO/106.

At RO/IN, the application must be filed in English or Hindi. In practice, English is strongly recommended: all eight ISAs competent for Indian applicants search in English, and a Hindi filing would require a verified translation before the search can begin, adding time and cost.

Biotechnology applications containing nucleotide or amino acid sequence listings must furnish the sequence listing in WIPO Standard ST.26 XML format. No fee is payable for sequence listings submitted in this format.

6. Choosing your ISA: The decision that shapes cost, quality and prosecution strategy

The International Searching Authority conducts the prior art search on your PCT application and produces the International Search Report and Written Opinion on patentability. Your ISA choice is one of the most consequential decisions in the entire PCT filing process – not because of the fee alone, but because of the downstream effects on prosecution quality, speed, and cost in your national phase markets.

Indian applicants filing through RO/IN can choose from eight ISAs, as confirmed in the WIPO PCT Applicant’s Guide for India (January 2026):

Source: WIPO PCT Fee Tables, 1 February 2026. ISA/IN INR amounts remain unchanged under the WIPO advance notice effective 1 May 2026 – the May change only affects the CHF equivalent (CHF 90 → CHF 84 for others; CHF 22 → CHF 21 for natural persons). USD equivalents are approximate and will vary with exchange rates.

Not sure which ISA to choose? The table below gives a quick starting point based on your primary target market. The strategic factors that follow explain the reasoning in detail.

Beyond cost, four factors should guide your ISA decision:

Search language and prior art coverage

IPO examiners search in English. EPO examiners search in English, German, and French. CNIPA examiners search Chinese-language prior art that no other ISA covers. If your invention is in a field where significant prior art is documented in Chinese – manufacturing processes, electronics components, materials science – CNIPA as ISA may produce a more thorough search. For most software, biotech, and general engineering inventions where prior art is predominantly in English, the difference between ISAs on search depth is less significant.

Patent Prosecution Highway eligibility

The Patent Prosecution Highway (PPH) allows a positive examination outcome from one patent office to be used to request accelerated examination at a partner office. ISAs from USPTO, EPO, JPO, and CNIPA are IP5 offices – a positive written opinion from any of them carries PPH weight across a wide network of partner offices. ISA/IN is not an IP5 member, so a positive written opinion from IPO does not unlock PPH acceleration at USPTO, EPO, JPO, or CNIPA. If your primary national phase targets are the US, Europe, China, and Japan, this is a material strategic consideration.

Downstream national phase fee offsets

Choosing EPO as your ISA has a specific financial benefit if you plan to enter the European regional phase: the EPO regional phase search fee (currently EUR 1,460) is waived if EPO was your ISA. This makes the ISA/EP fee of EUR 1,845 cost-neutral or even net-positive for applicants entering Europe. The USPTO also offers a discount on examination fees for applicants who chose it as ISA.

Unity of invention risk

ISAs differ in how strictly they apply unity of invention – the rule that an application must cover only one invention or a group of linked inventions. EPO is the strictest of the eight available ISAs, making additional search fees more likely for broad, multi-faceted claim sets. USPTO and IPO are generally more permissive. If your application covers multiple independent inventive concepts, a less strict ISA may reduce your international phase costs.

Expedited examination at Indian national phase – the ISA/IN advantage

One downstream benefit is unique to ISA/IN: applicants who choose the Indian Patent Office as ISA or IPEA are eligible to file a Request for Expedited Examination (Form 18A) when entering the Indian national phase. This places the application into a faster examination queue at the IPO – which matters for startups seeking an early Indian grant for fundraising, licensing, or enforcement. We explain exactly what this unlocks in prosecution in our article on choosing India as your PCT ISA.

7. PCT fees for Indian applicants: The complete 2026 breakdown

When you file a PCT international application, three separate fees are payable to the receiving office within one month of the international filing date. They flow to three different recipients: the transmittal fee stays with the RO, the international filing fee goes to the WIPO International Bureau, and the search fee goes to the ISA. If any fee remains unpaid after one month, the receiving office issues a formal invitation to pay under PCT Rule 16bis, with a late payment surcharge – so it is important to arrange payment promptly on filing rather than waiting for an invoice.

How the fee calculation works

The international filing fee is set by WIPO at USD 1,667 for applications up to 30 sheets (one side of a page = one sheet). Each sheet over 30 costs an additional USD 19. When you file electronically through ePCT with the request in character-coded format – the standard ePCT preparation mode – a reduction of USD 251 is applied automatically. This is called the Item 4(b) e-filing reduction and is built into ePCT’s fee calculator.

India is on the WIPO list of states whose natural person residents qualify for a 90% reduction in the international filing fee. The calculation sequence is critical: the e-filing reduction is applied first, then the 90% reduction is applied to the resulting sub-total – not to the original base fee. This sequence is explicitly confirmed in the WIPO Fee Tables footnotes.

The two scenarios below show what this means in practice for a typical Indian startup filing:

All figures from WIPO PCT Fee Tables (1 February 2026). USD equivalents for INR and EUR are approximate. Both scenarios assume ePCT electronic filing with the request in character-coded format (Item 4(b) reduction applied). Professional fees – patent agent charges – are separate from all government fees above.

8. The 90% fee reduction: Who qualifies and the assignment trap

The Scenario A calculation above assumes the applicant qualifies for the 90% reduction. Here is how to determine whether you do – and the trap that catches many startup founders.

India appears on the WIPO eligibility list (effective 7 January 2025), making the reduction available to Indian natural persons. For an individual Indian inventor filing their own PCT application, this is significant: the international filing fee drops from USD 1,667 to approximately USD 141–167 depending on page count.

However, in October 2017 the PCT Assembly adopted a formal Understanding clarifying that the 90% reduction applies only where the applicants named in the PCT request are the sole and true owners of the application, and are under no obligation to assign, grant, convey or license the rights in the invention to another party that is not itself eligible for the reduction.

What this means in practice for founders: if you have incorporated your startup and signed an IP assignment agreement – or if your employment contract, shareholder agreement, or investor agreement obligates you to assign the patent rights to a company or entity that does not itself qualify – you may not be entitled to the 90% reduction even if your individual name is on the PCT request. This should be reviewed with your patent agent before filing, not discovered during a WIPO fee audit.

9. What happens after you file: The international phase timeline

Once your PCT international application is filed and fees are paid, the international phase follows a fixed timetable. Several decisions – amending claims, requesting preliminary examination – are governed by hard deadlines that cannot be extended. Here is a quick overview before the full sequence:

Here is the full sequence with the decisions at each stage:

1. International filing date confirmed: Your receiving office issues Form PCT/RO/105 confirming the international filing date. This date anchors every subsequent deadline – if you claimed priority from an Indian application, all timelines run from that earlier priority date, not the PCT filing date.
2. Search copy transmitted to the ISA: The RO forwards a copy of your application to the ISA within one month of receipt, provided the search fee has been paid. If the search fee is unpaid, the search copy is not sent – delaying the ISR and potentially the entire examination timeline.
3. International publication at 18 months: WIPO publishes your application on PATENTSCOPE at 18 months from the priority date, regardless of whether the ISR is ready. Publication is automatic and cannot normally be prevented. From this point, your invention is in the public domain internationally.
4. International Search Report and Written Opinion (16–18 months from priority): The ISA issues the ISR and Written Opinion, typically within 16 months from the priority date. The Written Opinion gives a non-binding assessment of novelty, inventive step, and industrial applicability – your first indication of how national patent offices are likely to respond to your claims.
5. Article 19 amendment window (2 months from ISR transmittal): After receiving the ISR, you have 2 months to file amended claims under Article 19. These amendments let you narrow or refine your claims in response to the Written Opinion before national phase entry. For a full comparison of Article 19 and Article 34 amendment strategies, see our Article 19 vs Article 34 guide.
6. Optional Chapter II demand (by 22 months from priority): If the Written Opinion is negative and you want to argue patentability more fully before committing to national phase costs, you can file a demand for International Preliminary Examination with a competent IPEA. The demand must be filed before the later of 3 months from ISR transmittal or 22 months from the priority date. For Indian applicants, the competent IPEAs are ISA/IN, AT, AU, and SE.
7. National phase entry (30 or 31 months from priority): By 30 months from the priority date (31 months for India), you must file national or regional applications in every country where you want patent protection. This is when the substantial cost of international patenting is incurred. Missing this deadline is generally an absolute bar – most jurisdictions, including India, offer no reinstatement mechanism. For the full procedure on entering the Indian national phase, see our PCT national phase India guide.

10. Five mistakes Indian applicants make when filing PCT

These are the five errors Intepat sees most frequently when reviewing PCT filings by Indian startups and inventors – each one avoidable with a small amount of advance planning.

1. Missing the 12-month PCT window by mistracking the priority date. The 12-month window runs from your first Indian filing for this invention – which is the provisional application date, not the complete specification date filed later. Missing this deadline cannot be corrected through RO/IN: restoration of priority is not accepted under PCT Rule 26bis.3. Check this date before any other decision.

• Assuming Section 39 does not apply when filing through RO/IN. The Delhi High Court confirmed in Puneet Kaushik that a PCT international application filed through the Indian Patent Office is still a foreign application for Section 39 purposes. Section 39 compliance is mandatory regardless of which receiving office you use. The six-week wait must have actually elapsed before the PCT is filed – not just started.

• Choosing ISA on cost alone without considering downstream strategy. ISA/IN is the lowest-cost option and is genuinely appropriate for many Indian startups – particularly those whose primary goal is an early Indian grant. But if your primary national phase targets are the US, Europe, China, and Japan, the absence of PPH weight from an ISA/IN written opinion may increase prosecution time and cost in those jurisdictions. Match the ISA to your national phase plan, not just the filing budget.

• Losing the 90% fee reduction through an undisclosed assignment obligation. Founders who have assigned or are contractually obligated to assign patent rights to an entity not eligible for the reduction – including their own incorporated company – may not qualify for the 90% reduction even if their individual name is on the PCT request. This needs to be reviewed before filing, not discovered after a WIPO query.

• Filing on paper when electronic filing through ePCT is free and faster. Paper filing through RO/IN carries a transmittal fee of INR 3,500 (natural persons and startups) or INR 17,600 (companies), and forfeits the USD 251 Item 4(b) e-filing reduction on the international filing fee. Electronic filing via ePCT is transmittal-fee-free, processes faster, and is how the fee scenario calculations in this article are structured. There is no advantage to paper filing for a standard PCT application from India.

Ready to file your PCT application from India?

PCT filings are deadline-driven. Missing the 12-month priority window can permanently affect international patent rights – and unlike most other IP deadlines, there is no reinstatement mechanism through the Indian Patent Office.

Intepat IP assists Indian startups, MSMEs, universities, and inventors with Section 39 compliance, ISA strategy, ePCT preparation and submission, and fee calculation for every applicant category.

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