Patent Claim Types Explained: System, Apparatus, Method, Composition, Kit
A patent claim defines what is claimed. Its type tells you what kind of subject matter it is: a thing, a composition, a set of steps, or a stored program. This page walks through the main claim types with original example claims and MPEP sources, then links to our guides on each.
Last checked: October 26, 2026. Sources are USPTO MPEP sections, linked beside each point. The example claims were written for this page and are not taken from any patent. Wysebridge is an independent study resource and is not affiliated with the USPTO.
Start with the four statutory categories
US law lets you patent four kinds of things: a process, a machine, a manufacture, or a composition of matter. The MPEP says the statutory term “process” is synonymous with “method.” Machines, manufactures and compositions of matter are the types of physical or tangible things that can be patented. Source: MPEP 2106.03.
Every claim type below sits in one or more of those four. A claim does not have to fit only one: the MPEP's own example is a bicycle, which satisfies both the machine and manufacture categories. Source: MPEP 2106.03.
The examples below belong to one imaginary claim set about watering a plant. They are numbered so later claims can refer back to earlier ones.
System and apparatus claims
In the MPEP's words, a machine is a “concrete thing, consisting of parts, or of certain devices and combination of devices.” System and apparatus claims both recite things built from parts. Source: MPEP 2106.03. Our guides compare the two labels in practice.
Example 1 (written for this page): “1. A watering system comprising: a soil moisture sensor; a valve coupled to a water line; and a controller configured to open the valve when the sensor reports a moisture level below a threshold.”
Read more: System claim vs apparatus claim and system claim vs device claim.
Method claims
A method claim is a series of acts. It falls under the process category. Source: MPEP 2106.03.
Example 2: “2. A method of watering a plant, comprising: measuring a soil moisture level; comparing the level to a threshold; and opening a valve for a set time when the level is below the threshold.”
Read more: Method of making vs method of use.
Composition claims
A composition of matter is a combination of two or more substances, and includes all composite articles. Source: MPEP 2106.03. Composition claims are where the transitional phrase matters most:
- “Comprising” is inclusive or open-ended. It does not exclude additional, unrecited elements or method steps.
- “Consisting of” excludes any element, step or ingredient not specified in the claim.
- “Consisting essentially of” limits the claim to the specified materials or steps and those that do not materially affect the basic and novel characteristic or characteristics of the invention.
The MPEP adds that what a transitional phrase excludes must be decided case by case. Source: MPEP 2111.03.
Example 3: “3. A plant-feed composition consisting of water, nitrogen salt A, and phosphate salt B.”
Read more: Composition claim vs method claim and composition of matter vs method of treatment.
Kit claims
A kit claim recites items supplied together. MPEP 2111.03 discusses a court decision on a kit claim written with “consisting of,” which shows why the transitional phrase matters here too.
Example 4: “4. A plant-care kit comprising: a container of the composition of claim 3; and a moisture probe.”
Read more: Kit claim vs composition claim.
Computer-readable medium claims
A product claim must be to something with a physical or tangible form. The MPEP lists a computer program per se, claimed as a product without any structural recitations, and transitory forms of signal transmission, such as a propagating electrical or electromagnetic signal or carrier wave, among subject matter that is not directed to any statutory category. A claim to a computer readable medium that can be a compact disc or a carrier wave covers a non-statutory embodiment and should be rejected under 35 U.S.C. 101. Random-access memory and magnetic tape are statutory media. Source: MPEP 2106.03.
Example 5: “5. A non-transitory computer-readable medium storing instructions that, when executed by a processor, cause the processor to carry out the method of claim 2.”
Read more: Non-transitory medium vs signal claim.
Independent and dependent claims
A dependent claim refers back to and further limits another claim, and is construed to include all the limitations of the claim it refers to. Source: 37 CFR 1.75(c), reproduced in MPEP 608.01(n). A claim that does not refer back to another claim stands on its own as an independent claim.
Example 6: “6. The watering system of claim 1, wherein the controller is further configured to close the valve after a set time.”
Read: Dependent vs independent claim.
Watch antecedent basis. Writing “said spring” when no spring was introduced can make a claim unclear, but the MPEP says a failure to provide explicit antecedent basis does not always make a claim indefinite. If the scope of the claim would be reasonably ascertainable by those skilled in the art, the claim is not indefinite. Source: MPEP 2173.05(e).
How this shows up on the patent bar
The USPTO says the registration exam is designed to test knowledge of patent laws, rules and procedures and the ability to analyze factual situations, and that its questions are based on the MPEP and other published USPTO policy and procedure reference materials. Source: General Requirements Bulletin, Section IX.A. So learning to read a claim, name its category and find the governing MPEP section is time well spent.
Practice with the MPEP guide (start with chapters 2100 and 600), the free practice set, the exam simulator and our patent bar exam prep overview. For more on claims, read approaching claim analysis questions, the role of claim analysis on the exam and mastering patent claim drafting.
All claim guides
Every claim-related “what is the difference between” guide, grouped by topic. Some guides overlap; each one answers a slightly different search.
Statutory categories and claim form
- Product claims vs process claims in a patent
- A process patent vs a product patent
- A composition patent vs a process patent
- A composition claim vs a method claim
- A system claim vs an apparatus claim
- A system claim vs a device claim
- A use claim vs an apparatus claim
- A software claim vs a hardware claim
- A data carrier claim vs a system claim in software patents
- A utility patent vs a design patent in terms of claim structure
Composition, compound and kit claims
- A composition claim vs a method of use claim
- A compound claim vs a composition claim
- A kit claim vs a composition claim
- A composition of matter vs a method of treatment
- A genus claim vs a species claim
- A product claim vs a use claim in pharmaceutical patents
- A process of nature vs an industrial process
Product-by-process and Markush claims
- A product by process claim vs a process claim
- A process patent vs a product by process patent
- A markush claim vs a product by process claim
- A markush grouping vs a jepson claim
Method and process claims
- A method of making vs a method of use in patent claims
- A method of manufacturing vs a method of using
- A method of use claim vs a method of making claim
- A method of treatment claim vs a diagnostic method claim
- A method claim in a business method vs a software related method claim
- Software patents vs business method patents
- A utility invention vs a business method invention
Computer-readable medium claims
- A non transitory computer readable medium vs a computer readable storage medium
- A non transitory medium vs a signal claim
- A non transitory medium vs a transitory signal in patent claims
- A transitory claim vs a non transitory claim
Independent, dependent and multiple claims
- A dependent claim vs an independent claim
- A dependent claim vs an independent claim in patents
- A representative claim vs a dependent claim
- A representative claim vs a generic claim in patent prosecution
- A linking claim vs a multiple dependent claim
- A single claim patent vs a multiple claim patent
- A broad claim vs a narrow claim in terms of patent protection scope
Claim language: preambles, transitions, limitations
- A terminal part of a claim vs a preamble
- A terminal part of a claim vs a preamble of a claim in patent drafting
- A terminal part of a patent claim vs a preamble
- A transition phrase comprising vs consisting of in patent claims
- A transitional phrase comprising vs consisting essentially of in claim drafting
- A transitional phrase comprising vs consisting of in claim drafting
- A transitional part of a claim vs a characterizing part of a claim
- A negative limitation vs a positive limitation in patent claims
- A disclaimed term vs a defined term in patent claims
- An antecedent basis vs a claim differentiation
- Literal elements vs functional elements in a claim
- Written description vs definiteness in patent claim requirements
Functional and unusual claim forms
- A means plus function claim vs a step plus function claim
- Means plus function claims vs step plus function claims
- Functional claiming vs means plus function claiming
- An omnibus claim vs a jepson claim
- An omnibus claim vs a picture claim in patents
Claims and the specification
- An embodiment vs an example in patent specifications
- Exemplary embodiments vs preferred embodiments in patent specifications
- The specification vs the claims of a patent
- The written description vs the claims of a patent
- A specification support for a claim vs an original disclosure
- A claim chart vs a specification
Claims in prosecution and interpretation
- A claim amendment vs a claim cancellation
- A claim objection vs a claim rejection
- Claim broadening vs claim narrowing
- Claim broadening vs claim narrowing during patent prosecution
- A disavowal of claim scope vs a broadening of claim scope
- An original claim vs a new claim
- The claims of a parent application vs the claims of a divisional application
- A restriction requirement vs an election of species
- Claim construction vs claim interpretation
- The BRI vs the Phillips standard of claim interpretation