Provisional vs Complete Specification: Which Should You File First?
What each specification must contain, what a provisional really protects, and the fixed 12-month deadline.
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A provisional specification describes the invention and secures a priority date without claims; a complete specification fully describes the invention, discloses the best method of performing it and ends with claims that define the protection. If you start with a provisional, the complete specification must be filed within 12 months (section 9 of the Patents Act, 1970), or the application is treated as abandoned.
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On this page · 6 sections
How does a provisional differ from a complete specification?
Both are filed with Form 1 at the Indian Patent Office and both are part of the same application.
| Provisional specification | Complete specification | |
|---|---|---|
| Purpose | Secures a priority date early | Defines the invention and the protection sought |
| Claims | Not required | Required; they set the scope of the patent |
| Best method | Not required | Must disclose the best method known to the applicant |
| Examined? | No | Yes, after a request for examination on Form 18 |
| Deadline | — | Within 12 months of the provisional (s. 9(1)) |
| Term of the patent | Runs from the date the application was filed, so from the provisional date | Same application, same date of patent |
| Typical use | Early-stage inventions, before disclosure or fundraising | Finished inventions, or filing direct without a provisional |
Sections 7, 9 and 10 of the Patents Act, 1970 govern specifications. Both specifications are written in English or Hindi.
What does a provisional application actually protect?
A provisional application protects a date, not a scope. Under section 11, each claim of the later complete specification takes the priority date of the provisional only if the claim is fairly based on matter disclosed in the provisional. Anything added later takes the later date of the complete specification.
That is why a provisional is only as strong as its description. A one-page summary, a pitch deck or a list of features protects very little, because the claims you need later will not be fairly based on it. A good provisional reads like an early draft of the complete specification without the claims: the problem, the solution, how it works, the main embodiments, alternatives and variations, and drawings.
When a provisional makes sense
- Before any disclosure. You need to present at a conference, pitch to investors or test with customers in the next weeks.
- The invention is still moving. The core idea is settled but data, prototypes or variants will come in the next months.
- You need time to decide on foreign filing. The 12-month window from the provisional is also the window for PCT and Paris Convention filings abroad.
When to go straight to a complete specification
If the invention is finished and you already know what you want to claim, a complete specification on day one starts the examination clock sooner and avoids the risk of a thin provisional. It is also the natural choice where a corresponding foreign application already exists.
What is the timeline from provisional to complete?
Counted from the date the provisional is filed. Our patent deadline calculator gives the exact dates.
Month 0
Provisional filed
Form 1 and the provisional specification. The priority date is fixed for what it discloses.
+ 6 weeks
Foreign filing becomes possible
Indian residents may file abroad six weeks after the Indian filing if no secrecy direction issues, or earlier with permission on Form 25.
Months 8–10
Draft the complete specification
Collect data, decide the claim strategy and run a patentability search if you have not.
Month 12
Complete specification and foreign filings
The complete specification is filed in India; a PCT or Paris Convention application must also be filed by this date to keep priority abroad.
Month 18
Publication
The application is published in the Patent Office Journal, unless early publication was requested.
Month 31
Request for examination
Form 18 is due within 31 months of the priority date for applications filed on or after 15 March 2024.
What should a good provisional specification include?
Enough detail that the claims you will want in twelve months are fairly based on it.
- Field and problem. What the invention relates to and the technical problem it solves.
- How it works. The structure, steps or composition, described so that a skilled person could follow it.
- Embodiments and variations. The preferred version and the alternatives you can foresee, including ranges for any parameters.
- Drawings. Block diagrams, flow charts or sketches, labelled and referred to in the text.
- Advantages and results. Test data or expected effects, especially for chemical, pharmaceutical and biological inventions.
- What it is not. Avoid marketing language and statements that limit the invention to one product.
Can a provisional be combined, converted or extended?
The Act allows some flexibility, but not more time.
- Several provisionals, one complete. Under section 9(2), where two or more provisional applications relate to cognate inventions, one complete specification can be filed for all of them within 12 months of the earliest. Each claim takes the priority of the provisional that supports it.
- Complete treated as provisional. Under section 9(3), an applicant who filed a complete specification can ask, within 12 months of filing, for it to be treated as a provisional, which allows a fuller complete specification later.
- No extension of the 12 months. The deadline for the complete specification cannot be extended. If it is missed, the application is treated as abandoned and the priority date is lost, and any disclosure made in the meantime counts against a new application.
If you are weighing these options, our provisional patent application service and patent filing team can review your draft before the deadline.
Questions about provisional and complete specifications
Is a provisional patent application a patent?
No. It is the first part of a patent application that secures a priority date. No patent is granted until a complete specification is filed, examined and accepted.
Can I publicly disclose my invention after filing a provisional?
Disclosure of what the provisional describes is safer after filing, because the priority date is earlier. Anything not in the provisional is still unprotected, so check the content before disclosing.
Does a provisional application get examined?
No. Only the complete specification is examined, and only after a request for examination on Form 18.
From when does the 20-year patent term run?
From the date the application was filed. Where the application began with a provisional, that is the provisional filing date, so the provisional year is part of the term.
Can I file a provisional in India and the complete in the USA?
No. The Indian complete specification belongs to the Indian application. A US application filed within 12 months can claim priority from the Indian provisional, but it is a separate application.
What happens if I miss the 12-month deadline?
The Indian application is treated as abandoned. You can file afresh, but the new application takes the new date and may be blocked by your own disclosures made in the meantime.
Can a provisional application be filed without drawings?
Yes, drawings are not compulsory, but they usually make the description clearer and give the later claims a firmer basis. Most mechanical, electrical and software inventions benefit from at least a block diagram or flow chart.
Does the complete specification have to repeat the provisional word for word?
No. It can expand, refine and add claims. What matters is that the claims you want to date from the provisional are fairly based on what the provisional disclosed; new matter takes the later date.
