How to Write a Patent Claim

Man writing patent claim
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Claims are the parts of a patent which define the boundaries of patent protection. Patent claims are the legal basis for your patent protection. They form a protective boundary line around your patent that lets others know when they are infringing on your rights. The limits of this line are defined by the words and phrasing of your claims.

As the claims are key to receiving complete protection for your invention, you may wish to seek professional help to ensure that they are properly drafted. When writing this section you should consider the scope, characteristics, and structure of the claims.


Each claim should have only one meaning which can be either broad or narrow, but not both at the same time. In general, a narrow claim specifies more details than a broader claim. Having many claims, where each one is a different scope allows you to have legal title to several aspects of your invention.

Claim 8 of the same patent is narrower in scope and focuses on a specific aspect of one element of the invention. Try reading through the claims for this patent and notice how the section begins with broad claims and develops towards claims that are narrower in scope.​

Important Characteristics

Three criteria to take note of when drafting your claims are that they should clear, complete, and supported. Every claim must be one sentence, as long or as short a sentence as required to be complete.

Be Clear

Your claim must be clear so that you do not cause the reader to speculate about the claim. If you find yourself using words such as "thin", "strong", "a major part", "such as", "when required", then you are probably not being clear enough. These words force the reader to make a subjective judgment, not an objective observation.

Be Complete

Each claim should be complete so that it covers the inventive feature and enough elements around it to put the invention in the proper context.

Be Supported

The claims have to be supported by the description. This means that all the characteristics of your invention that form part of the claims must be fully explained in the description. In addition, any terms you use in the claims must be either found in the description or clearly inferred from the description.


A claim is a single sentence composed of three parts: the introductory phrase, the body of the claim, and the link that joins the two.

The introductory phrase identifies the category of the invention and sometimes the purpose, for example, a machine for waxing paper, or a composition for fertilizing soil. The body of the claim is the specific legal description of the exact invention which is being protected.

The linking consists of words and phrases such as:

  • which comprises
  • including
  • consisting of
  • consisting essentially of

Note that the linking word or phrase describes how the body of the claim relates to the introductory phrase. The linking words are also important in assessing the scope of the claim as they can be restrictive or permissive in nature.

In the following example, "A data input device" is the introductory phrase, "comprising" is the linking word, and the rest of the claim is the body.

Example of a Patent Claim

"A data input device comprising: an input surface adapted to be locally exposed to a pressure or pressure force, a sensor means disposed below the input surface for detecting the position of the pressure or pressure force on the input surface and for outputting an output signal representing said position and, an evaluating means for evaluating the output signal of the sensor means."

Keep in Mind

Just because one of your claims is objected to does not mean that the rest of your claims are invalid. Each claim is evaluated on its own merit. This is why it is important to make claims on all aspects of your invention to ensure that you receive the most protection possible. Here are some tips on writing your claims.

  • Decide which are the essential elements of your invention that you want to claim exclusive rights to. These elements should be the ones that distinguish your invention from known technology.
  • Begin with your broadest claims and then progress to narrower claims.
  • Start claims on a new page (separate from the description) and number each claim using Arabic numbers starting with 1.
  • Precede your claims with a short statement such as "I claim:". In some patents, this reads as "The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:"
  • Check to see that each claim consists of an introduction, linking word, and body.

One way of ensuring that specific inventive features are included in several or all claims is to write an initial claim and refer to it in claims of narrower scope. This means that all the features in the first claim are also included in the subsequent claims. As more features are added the claims become narrower in scope.