How to write patent claims, with examples

What patent claims do

The description explains the invention; the claims say what no one else may make, use, sell or import without consent. 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. Novelty and inventive step are judged claim by claim, a claim can be rejected or revoked on its own, and each claim must be supported by the description. Too broad, and a claim reads on the prior art; too narrow, and a competitor avoids it by changing one detail.

Examiners read claims broadly. The USPTO gives a pending claim its broadest reasonable interpretation consistent with the specification (MPEP 2111). The EPO always consults the description and drawings when interpreting a claim, not only when the claim is unclear (Guidelines F-IV 4.2, following G 1/24). In both cases, write the claim so it means what you intend without help from the description.

Anatomy of a claim

A claim is written as a single sentence in three parts. The USPTO insists on this: each claim begins with a capital letter, ends with a period, and has no other periods except in abbreviations (MPEP 608.01(m)).

• 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 three common transition phrases mean nearly the same at the USPTO and the EPO. The Indian Patents Act does not define them, but Indian drafters and examiners use them the same way.

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 (35 U.S.C. 112(d), Rule 43(4) EPC). Take a table whose legs snap into sockets under the top, so it can be assembled without tools.

An apparatus claim and its dependents

A method claim

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. US drafts usually write "The table of claim 1"; European and Indian drafts often write "The table according to claim 1" or "as claimed in claim 1". Either wording works at every office.

The same set is treated differently by office. At the USPTO, claim 3 triggers the multiple dependent claim fee and counts as two claims toward the 20-claim threshold. At the EPO, claim 1 would usually be recast in two-part form with reference signs. In India, rule 13(4) requires the reference signs. The office sections below show each version.

Claim categories by office

Every office recognizes two basic kinds of claim: claims to a thing (a product, apparatus or system) and claims to an activity (a process or method). Where they differ is on software, medical methods and claims to a new use.

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.

No office lets you add new matter after filing: not the USPTO (35 U.S.C. 132(a)), not the EPO (Art. 123(2) EPC), not India (section 59(1)). A fallback only exists if the application as filed describes it. So put each useful variation in the description, and the most important ones in dependent claims, before you file. At the EPO, note that "comprising" in the application as filed is not by itself a basis for amending to "consisting of" (F-IV 4.20), so describe the closed version too if you may need it.

The same applies to a provisional application. Neither a US nor an Indian provisional needs claims, but a later claim takes the provisional's date only if the provisional supports it (35 U.S.C. 119(e)(1); section 11(2) in India). See provisional patent applications in the US and provisional vs complete specification in India.

Claim rules by office: USPTO, EPO and India

The table puts the main differences side by side. Fees are as of October 25, 2026. The sections after it explain each office in more detail.

Writing claims for the USPTO

Definiteness: 35 U.S.C. 112(b)

The specification must "conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention" (35 U.S.C. 112(b)). A court finds a granted claim indefinite if, read with the specification and prosecution history, it fails to inform those skilled in the art about the scope of the invention with reasonable certainty (Nautilus v. Biosig, 2014). Examiners apply the test more strictly: if a skilled person would read the claim, given its broadest reasonable interpretation, with more than one reasonable interpretation, it can be rejected (MPEP 2173.02). The usual 112(b) problems, all covered in MPEP 2173.05:

• Antecedent basis: "said lever" with no earlier "a lever", or "said aluminum lever" when only "a lever" was introduced (MPEP 2173.05(e)). 37 CFR 1.75(d)(1) also requires every claim term to find clear support or antecedent basis in the description.
• Terms of degree: words such as "thin" or "about" are allowed if a skilled person would understand them in light of the specification (MPEP 2173.05(b)). Give the description a standard to measure them against.
• Examples in the claim: "such as" and "for example" do not make a claim indefinite by themselves, but they can leave it unclear whether the narrower example is a limitation (MPEP 2173.05(d)). Put examples in the description and in dependent claims.
• Use claims: "a process for using X" with no active steps is indefinite (MPEP 2173.05(q)). Write "a method of ..., comprising" followed by steps.

Means-plus-function: 35 U.S.C. 112(f)

An element in a combination claim may be written as "a means or step for performing a specified function" without the structure. Such a claim "shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof" (35 U.S.C. 112(f)). So "means for holding each leg in the respective socket" would cover the resilient latch the description shows and its equivalents, not every way of holding a leg.

Section 112(f) is not limited to the word "means". Examiners apply it when a claim uses "means", "step" or a generic placeholder such as "module" or "unit", modified by functional language ("for", "configured to", "so that"), without enough structure to perform the function (MPEP 2181, the 3-prong test). For a computer-implemented function, the specification must disclose an algorithm for it, or the claim is indefinite under 112(b) (MPEP 2181 II.B). If you do not want 112(f), recite the structure.

Form of claims: 37 CFR 1.75

• Claims start on a separate sheet or page (1.75(h)), are numbered consecutively in Arabic numerals (1.75(f)), and each element or step is separated by a line indentation (1.75(i)).
• The least restrictive claim should be claim 1, and dependent claims grouped with the claims they refer to (1.75(g)).
• Claims must "differ substantially from each other and [not be] unduly multiplied" (1.75(b)).
• A multiple dependent claim must refer to earlier claims "in the alternative only" and cannot serve as the basis for another multiple dependent claim (1.75(c), 35 U.S.C. 112(e)). "The machine of claim 3 or 4" is fine; "claims 3 and 4" is not (MPEP 608.01(n)).
• Reference characters from the drawings may be used in the claims, in parentheses. They generally do not affect the scope (MPEP 608.01(m)).

Claim fees and the 3/20 thresholds

The basic filing, search and examination fees cover 3 independent claims and 20 claims in total. Beyond that, 37 CFR 1.16 adds the fees below (USPTO fee schedule, effective January 19, 2025). The fees apply to claims presented at filing or later, so an amendment that takes the count over a threshold triggers them too.

For the count, a multiple dependent claim is treated as the number of claims it refers to, and so is any claim that depends on it (37 CFR 1.75(c)). Claim 3 in the example above counts as two. This is why many US claim sets avoid multiple dependent claims and instead repeat the dependent claim once for each parent.

Jepson claims

37 CFR 1.75(e) describes an improvement claim: a preamble with the known elements, a phrase such as "wherein the improvement comprises", then the new part. In the table example:

The rule says "should", but US practitioners rarely use the form. Writing a Jepson claim is taken as an implied admission that the preamble is the prior art of another (MPEP 2129, In re Fout). A standard "comprising" claim avoids that admission.

Writing claims for the EPO

Clarity and support: Article 84 EPC

"The claims shall define the matter for which protection is sought. They shall be clear and concise and be supported by the description" (Art. 84 EPC). The Guidelines for Examination, Part F, Chapter IV, set out how examiners apply it. The points that most often cause objections:

• Relative terms: "thin", "wide" or "strong" are objected to unless they have a recognized meaning in the field, such as "thin-film transistor", or are clear from the whole disclosure (F-IV 4.6).
• Optional features: "preferably", "such as" or "in particular" are allowed only if they cause no ambiguity. "Heated to between 65 and 85°C, particularly to 90°C" is unclear (F-IV 4.9).
• References to the drawings: except where absolutely necessary, a claim may not say "as illustrated in figure 2" (Rule 43(6)).
• Functional features: a claim may define a feature by its function even with only one example, if the skilled person would see that other means could do the same job (F-IV 6.5). "Means for" covers any means suitable for the function, so it is anticipated by any prior art that can perform it (F-IV 4.13.2). This is broader than the US reading under 112(f).
• Conciseness: the number of claims must be reasonable for the invention (Rule 43(5)), and repeated wording between claims should be replaced by the dependent form (F-IV 5).

The two-part form: Rule 43(1)

Wherever appropriate, an independent claim has two parts. The preamble names the subject and the features which, in combination, are part of the prior art. The characterising portion begins "characterised in that" or "characterised by" and states the new features (Rule 43(1)(a) and (b)). The split is made against the closest prior art. If one document shows a feature from the second part in combination with all the preamble features, the examiner will ask for it to be moved into the preamble (F-IV 2.2). If the closest prior art were a table with legs that screw into sockets, claim 1 would read:

The two-part form is not required where it would give a distorted picture of the invention: a combination of known parts of equal status, a modification of a known chemical process, a complex system of interrelated parts, or a new chemical compound (F-IV 2.3). Dependent claims never need it.

One independent claim per category: Rule 43(2)

An application may contain more than one independent claim in the same category (product, process, apparatus or use) only if it involves one of three situations (Rule 43(2)):

• (a) Interrelated products: a plug and a socket, a transmitter and a receiver, an intermediate and the final chemical product (F-IV 3.2).
• (b) Different uses of a product or apparatus, such as further medical uses.
• (c) Alternative solutions to a particular problem, where one claim cannot cover them, such as a group of chemical compounds.

Claims in different categories are fine together: a product, a process for making it and a use of it, for example (F-IV 3.1). The table and the method of assembling it in our example are one product claim and one process claim, so they meet Rule 43(2). An unjustified extra independent claim leads to an objection, a search restricted under Rule 62a, and refusal if it is kept without a good argument (F-IV 3.3).

Reference signs: Rule 43(7)

Where the application has drawings with reference signs, the features in the claims should be followed by those signs in parentheses if that makes the claim easier to understand. They "shall not be construed as limiting the claim" (Rule 43(7)). In the two-part form, put them in the preamble as well as the characterising portion. Do not add words inside the parentheses, as in "securing means (screw 13, nail 14)": that is not a reference sign, and it makes the claim unclear (F-IV 4.18).

Claims fees above 15 claims: Rule 45

An application with more than 15 claims pays a claims fee for the 16th and each later claim (Rule 45(1)). From 1 April 2026 the fee is €290 per claim for claims 16 to 50 and €720 per claim from the 51st (Rules relating to Fees, Art. 2(1), item 15). It is due within one month of filing the first set of claims. If it is not paid after a reminder, the claim is deemed abandoned (Rule 45(2) and (3)). The EPO charges no extra fee for multiple dependent claims, which is why European claim sets use them freely: "according to any one of claims 1 to 3".

Amendments may not add subject-matter beyond the application as filed (Art. 123(2)) and, after grant, may not extend the protection (Art. 123(3)). A use claim is acceptable at the EPO and is read as a process claim (F-IV 4.16).

Writing claims for the Indian Patent Office

What the Patents Act requires

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)). A provisional needs no claims. The rights a claim gives are those in section 48: for a product, making, using, offering for sale, selling and importing; for a process, using it and dealing in the product obtained directly by it.

Each claim has its own priority date (section 11(1)). 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. 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)).

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.

Where the features in the claims appear in the drawings, rule 13(4) requires their reference signs in parentheses, for example "a top (10)". Section 3 lists what is not an invention, and several of its clauses shape claims directly: 3(d) for new forms and new uses of known substances, 3(i) for methods of treatment and 3(k) for computer programmes per se. The full text of section 3 is on this site.

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.

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. For the EPO, keep to one per category unless Rule 43(2) allows more.
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. Remove relative words without a measure, “etc.”, “and the like” and optional language such as “preferably” inside a claim.
9. Add reference signs in parentheses for the EPO and India. They are optional in the US.
10. Use “means for” only on purpose. In the US it limits the claim to the structure you described; at the EPO it reaches anything that can perform the function.
11. Check the exclusions for each office: subject-matter eligibility in the US (MPEP 2106), Art. 53 EPC in Europe, and sections 3(d), 3(i) and 3(k) in India.
12. Count the claims against each fee threshold: 3 independent and 20 total at the USPTO, 15 at the EPO, 10 in India. Avoid multiple dependent claims in a US filing unless they are worth the fee.
13. 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. You can search US and European patents for free on our USPTO and EPO search pages. For where claims fit in an Indian 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 survives US eligibility review (MPEP 2106), the EPO's exclusions or section 3(d) or 3(k) in India 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.

More patent guides

• Patent drawing requirements: USPTO, EPO and India

  37 CFR 1.84, the EPO rules that replaced Rule 46 EPC, and Indian rule 15, compared side by side.

• Types of patent searches, and which one you need

  Patentability, freedom-to-operate, invalidity and landscape searches compared by purpose, timing, scope and deliverable.

• Patentability search: how to check novelty before you file

  What counts as prior art under 35 U.S.C. 102 and Art. 54 EPC, the grace period gap, search steps and how to read results.

• Freedom-to-operate search in the US and Europe

  In-force claims only, legal status checks at the USPTO, EPO and UPC, FTO opinions after Halo, and design-arounds.

• Invalidity search: prior art to challenge a patent

  IPR, PGR, EPO opposition and UPC revocation deadlines, prior art dates, standards documents and claim charts.

• Patent landscape analysis, step by step

  Building a CPC and keyword dataset, cleaning families and names, the metrics that matter and the 18-month publication lag.

• Google Patents search guide

  Search operators and fields, Boolean and proximity syntax, non-patent literature, and where Google Patents falls short of the official databases.

• The Cooperative Patent Classification (CPC), explained

  How CPC symbols are built, CPC against IPC, the Y section, how to find the right class and how to search it in each database.

• Patent search Boolean operators and search strings

  Boolean, proximity and truncation syntax compared across Patent Public Search, Espacenet, Google Patents and The Lens, with semantic search for contrast.

• The PCT application: timeline, fees and national phase

  The international phase month by month, receiving Office and ISA fees in CHF, USD and EUR, national phase deadlines by office, and a deadline calculator.

• How much does a patent cost?

  USPTO fees by entity size from filing to the last maintenance fee, what drives professional fees, EPO fees, and an estimator.

• How long does a patent last?

  US utility and design terms, patent term adjustment and extension, terminal disclaimers, maintenance fee deadlines, Europe and India, with an expiry estimator.

• Can AI write a patent application?

  What AI drafting does well and badly, the USPTO and EPO positions on AI tools, AI inventorship after 2025, and confidentiality.

• PCT national phase deadlines by country

  30, 31 or more months: the national phase time limit at every office in WIPO's table, late-entry options and a deadline calculator.

• PCT search report, written opinion and Chapter II

  How to read the international search report and written opinion, Article 19 amendments, informal comments, and when a Chapter II demand is worth filing.

All guides, by patent office