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Patent drafting guide

How to write patent claims, with examples

By , Co-founder and CEO, PatentAssist.ai
Updated

The claims are the part of a patent that sets its legal limits. In India, every complete specification must end with "a claim or claims defining the scope of the invention for which protection is claimed" (section 10(4)(c)). This guide explains how a claim is built, how independent and dependent claims work together, and the drafting mistakes that lead to objections at the Indian Patent Office.

Quick answer

  • Structure: each claim is one sentence: a preamble, a transition word such as "comprising", and a body listing the elements or steps.
  • Claim set: one or more broad independent claims, each followed by dependent claims that add features as fallbacks.
  • The law in India: claims must relate to a single inventive concept, be clear and succinct, and be fairly based on the description (section 10(5)).
  • Watch for: sections 3(d) for drugs, 3(i) for treatments and 3(k) for software, and fees for every claim over 10.

What patent claims do

The description explains the invention; the claims say what no one else may make, use, sell or import without consent (section 48). Anything described but not claimed is not protected, and once published it becomes prior art against later applications, including your own. So the claims decide how much the patent is worth.

Claims are also the unit the law works on. Each claim has its own priority date (section 11(1)), novelty and inventive step are judged claim by claim, and a patent can be revoked if the scope of any claim is not sufficiently and clearly defined or a claim is not fairly based on the specification (section 64(1)(i)). Too broad, and a claim reads on the prior art; too narrow, and a competitor avoids it by changing one detail.

Anatomy of a claim

A claim is written as a single sentence in three parts.

  • Preamble: names the category and subject of the claim, such as "A table" or "A method of assembling a table". Keep it short; a purpose stated here may be read as limiting the claim.
  • Transition: the word that links the preamble to the body and sets whether the claim is open or closed.
  • Body: the elements of a product, or the steps of a process, and how they relate to each other. Each element is introduced once with "a" or "an" and referred back to with "the" or "said". This is called antecedent basis.

The meaning of the common transition phrases below is general patent drafting convention, developed largely in US and European practice. The Indian Patents Act does not define them, but Indian drafters and examiners use them the same way.

Transition phrases in patent claims and what they mean
Phrase Scope
"comprising" Also: including, containing Open. The claim covers anything that has all the listed elements, even if it has more. The usual choice.
"consisting of" Closed Closed. The claim covers only the listed elements and nothing else. A product with one extra element falls outside it. Mostly used for compositions.
"consisting essentially of" Partly closed In between. Extra elements are allowed only if they do not materially change the basic character of the invention. Used for compositions; how it is read varies by country, so use it with care.

Independent and dependent claims, with examples

An independent claim stands on its own. A dependent claim refers back to an earlier claim and adds a feature, so it includes everything in that claim plus something more. Take a table whose legs snap into sockets under the top, so it can be assembled without tools.

An apparatus claim and its dependents

1. A table, comprising:
a top having a lower surface;
a plurality of sockets on the lower surface; and
a plurality of legs, each leg having a first end received in a respective one of the sockets,
wherein each leg is held in the respective socket by a snap-fit and is removable from the socket.

2. The table as claimed in claim 1, wherein each socket comprises a resilient latch, and each leg has a groove near the first end that the latch engages.

3. The table as claimed in claim 1 or claim 2, wherein each leg has a second end opposite the first end, and a foot cap is fitted to the second end.

A method claim

4. A method of assembling a table, the method comprising:
providing a top having a plurality of sockets on a lower surface of the top;
inserting a first end of each of a plurality of legs into a respective one of the sockets; and
pushing each leg into the respective socket until a snap-fit holds the leg in the socket.

5. The method as claimed in claim 4, further comprising pulling each leg out of the respective socket to disassemble the table.

Notice the antecedent basis. Claim 1 introduces "a top", "a plurality of sockets" and "a plurality of legs"; every later mention uses "the". Claim 2 introduces "a resilient latch" and "a groove" before referring to "the latch". Writing "wherein the latch engages the groove" in claim 2 without introducing either would leave the claim unclear, because nothing in claim 1 says what "the latch" is.

Claim 3 is a multiple dependent claim: it refers to claim 1 or claim 2 in the alternative. Claim 4 is a second independent claim in a different category. It shares the snap-fit socket idea with claim 1, which keeps the set to a single inventive concept. Where the features in the claims appear in the drawings, rule 13(4) asks for their reference signs in parentheses, for example "a top (10)".

Claim categories and how India treats them

The Act defines an invention as "a new product or process" with an inventive step and industrial application (section 2(1)(j)), and the rights it grants are framed the same way (section 48). Every claim should therefore read as a product or a process.

Patent claim categories and how Indian practice treats them
Category In India
Product Device, apparatus, composition, compound, kit Protects making, using, offering for sale, selling and importing the product (section 48(a)). New forms of known substances meet section 3(d), and mere admixtures section 3(e).
Process Method of making, method of operating, method of use Protects using the process and the product obtained directly by it (section 48(b)). Methods of treating humans or animals are excluded by section 3(i), and agricultural methods by section 3(h).
System Components that work together, often with software Treated as a product claim. For software, the claim must recite more than a computer programme per se or an algorithm (section 3(k)).
Use “Use of X for treating Y” The Act defines an invention as a new product or process (section 2(1)(j)), and a new use of a known substance is excluded by section 3(d). Use claims are generally not accepted; recast the idea as a product or process claim if it can be.

Building a claim set with fallbacks

Draft the claims as layers. The independent claim carries only the features needed to solve the problem, so it is as broad as the prior art allows. Each dependent claim adds one feature with its own technical benefit. If the examiner cites prior art against claim 1, a dependent claim that survives can be folded into it.

Fallbacks matter more in India because of section 59(1): after filing, a claim can be amended only by disclaimer, correction or explanation, every amended claim must fall wholly within the scope of a claim before the amendment, and no amendment may add matter not in substance disclosed. You can narrow, never broaden. So put each useful variation in the description, and the most important ones in dependent claims, before you file.

If a provisional was filed first, a claim in the complete specification takes the provisional's date only if it is fairly based on matter the provisional disclosed (section 11(2)). See provisional vs complete specification.

Common claim objections in India

Section 10(5) sets the three tests every claim set must pass: the claims must relate to a single invention or a group linked by a single inventive concept, be clear and succinct, and be fairly based on the matter disclosed in the specification. Most claim objections in a First Examination Report come back to these tests or to section 3.

Common objections to patent claims in India and how to avoid them
Objection Cause and how to avoid it
Claims not clear or succinct s.10(5), s.64(1)(i) Missing antecedent basis, relative words (“about”, “substantially”, “high”) without a measure, “etc.” or “and the like”, and inconsistent terms. Use one name per element and define any range with numbers.
Claims not fairly based on the description s.10(5), s.64(1)(i) A claim is broader than what the description supports, or uses a feature the description never mentions. Describe every feature and variation you claim, and generalise in the description, not only in the claims.
Lack of unity of invention s.10(5), s.16 The claims cover more than one invention without a single inventive concept linking them. Delete or restrict the unrelated set, and file a divisional application for it before grant if you want to keep it.
Not an invention: new form of a known substance s.3(d) Salts, esters, polymorphs, isomers and other derivatives are treated as the known substance unless they differ significantly in efficacy. Claim the form only with data in the specification showing that difference.
Not an invention: computer programme per se s.3(k) A claim that is in substance a mathematical or business method, a computer programme per se or an algorithm. Claim the technical problem and the technical means that solve it, not the bare steps of the program.
Method of treatment s.3(i) Medical, surgical, diagnostic or therapeutic treatment of humans or animals is not an invention. Claim the composition, device or kit instead.
Lack of novelty or inventive step s.2(1)(j), s.2(1)(ja) The independent claim reads on the prior art. Search before drafting, and keep fallback features in dependent claims so the claim can be narrowed in the reply.

A divisional application under section 16 can be filed at any time before grant, either by choice or to meet a unity objection. It must not include matter not in substance disclosed in the parent's complete specification, and it is deemed filed on the parent's filing date. For how to reply once objections arrive, see responding to a First Examination Report.

Claims also affect the fee. The filing fee covers 10 claims; each claim over 10 costs ₹320 for a natural person, startup, small entity or educational institution and ₹1,600 for others, filed online (First Schedule, entries 1 and 2). See patent fees in India.

Claim drafting checklist

  1. Search the prior art first, so the independent claim is drawn around what is actually new.
  2. Write the broadest independent claim that the prior art leaves open, with only the features needed to solve the problem.
  3. Add an independent claim in each category you need: product, process of making, method of operating.
  4. Give every element an antecedent: introduce it with “a” or “an”, then refer back with “the” or “said”.
  5. Use one term for one element throughout the claims and the description.
  6. Add dependent claims that narrow step by step, each a real fallback with a technical reason behind it.
  7. Check that every claimed feature, and every alternative, is described in the specification.
  8. Add reference signs from the drawings in parentheses after claimed features (rule 13(4)).
  9. Remove relative words without a measure, “etc.”, “and the like” and optional language such as “preferably” inside a claim.
  10. Check the claims for sections 3(d), 3(i) and 3(k) if the invention is a drug, a treatment or software.
  11. Count the claims: each claim over 10 adds a filing fee.
  12. Read each claim as a competitor would: can it be avoided by dropping or swapping one element?

A prior art search before the first step is what makes the rest work. For where claims fit in the whole filing, see how to file a patent in India.

Where AI drafting tools help, and where they do not

AI drafting tools are good at the mechanical parts of claim drafting: turning an invention disclosure into a structured first claim set, keeping terms consistent, introducing every element before it is referred back to, and adding reference signs. They do this in minutes, which leaves more time for the decisions that matter.

Those decisions still need a person. How broad the independent claim can be depends on the prior art and on what competitors are likely to build. Which fallbacks are worth a dependent claim depends on the business. Whether a claim will meet section 3(d) or 3(k) depends on the data and the technical effect behind it. AI output is a draft to review, not a filing. For more, see AI patent drafting.

Draft a first claim set

PatentAssist.ai drafts independent and dependent claims, the complete specification and the abstract in IPO format from your invention disclosure, ready for your review.

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Writing patent claims: frequently asked questions

How do you write a patent claim?

Start with a preamble naming what the invention is, add a transition word (usually “comprising”), then list the elements or steps and how they connect. Introduce each element with “a” or “an” and refer back to it with “the”. Write one broad independent claim, then dependent claims that add one feature each as fallbacks.

What is the difference between independent and dependent claims?

An independent claim stands on its own and defines the widest protection. A dependent claim refers to an earlier claim and adds a feature to it, so its scope is narrower. If the independent claim is found to lack novelty or inventive step, a dependent claim can become the new main claim.

How many claims can a patent application have in India?

The Act sets no maximum. The filing fee covers up to 10 claims; each claim over 10 costs ₹320 for a natural person, startup, small entity or educational institution and ₹1,600 for other applicants, filed online (First Schedule, entries 1 and 2).

What does “comprising” mean in a patent claim?

By general drafting convention, “comprising” is open: the claim covers anything with all the listed elements, even if it has others. “Consisting of” is closed and covers only the listed elements. The Indian Patents Act does not define these words; their meaning comes from drafting practice and case law.

Can claims be broadened after filing in India?

No. Under section 59(1), every amended claim must fall wholly within the scope of a claim before the amendment, and the amendment may not add matter not in substance disclosed. Claims can be narrowed, but not broadened, so file the broadest claim you can support from the start.

Do claims need to be in the provisional specification?

No. A provisional needs no claims; the complete specification must end with them (section 10(4)(c)). But a claim gets the provisional's date only if it is fairly based on what the provisional disclosed (section 11(2)), so the provisional should describe everything you may later claim.

Can AI write patent claims?

AI tools can produce a structured first draft of a claim set quickly, with consistent terms and antecedent basis. Deciding how broad the main claim should be, which fallbacks matter commercially and how to avoid section 3 exclusions still needs a person who understands the invention, the prior art and the business. Every claim should be reviewed before filing.

Sources: Patents Act, 1970, sections 2, 3, 10, 11, 16, 48, 59 and 64; Patents Rules, 2003, rule 13 and the First Schedule. The meanings of transition phrases are general drafting convention, not Indian statute. This guide is general information, not legal advice. Have claims for a real application reviewed by a registered patent agent.