Qualifying for a Patent FAQs

Learn whether your invention is eligible for patent protection.

By , Attorney · Benjamin N. Cardozo School of Law
Updated by Glen Secor ·, Attorney · Suffolk University Law School


What types of inventions can be patented?

The USPTO issues three different kinds of patents: utility patents, design patents, and plant patents.

To qualify for a utility patent, by far the most common type of patent, an invention must be:

  • a process or method for producing a useful, concrete, and tangible result (such as a genetic engineering procedure, an investment strategy, computer software, or a process for conducting e-commerce on the Internet)
  • a machine (usually something with moving parts or circuitry, such as a cigarette lighter, a sewage treatment system, a laser, or a photocopier)
  • an article of manufacture (such as an eraser, a tire, a transistor, or a hand tool)
  • a composition of matter (such as a chemical composition, a drug, a soap, or a genetically altered lifeform), or
  • an improvement of an invention that fits within one of the first four categories.

If an invention fits into one of the categories described above, it is known as "statutory subject matter" and has passed the first test in qualifying for a patent. But an inventor's creation must overcome several additional hurdles before the USPTO will issue a patent. The invention must also:

  • have some usefulness (utility), no matter how trivial
  • be novel (that is, be different from all previous inventions in some important way)
  • be nonobvious (a surprising and significant development) to somebody who understands the technical field of the invention.

For design patents, the law requires that the design be novel, nonobvious, and nonfunctional. For example, a new shape for a car fender, a bottle, or a flashlight that doesn't improve its functionality would qualify.

Finally, plants may qualify for a patent if they are both novel and nonobvious. Plant patents are issued less frequently than any other type of patent, since they generally are finales by large agricultural or pharmaceutical companies.

The following items are just some of the things that might qualify for patent protection:

biological inventions

business methods

carpet designs

chemical formulas or processes

clothing accessories and designs

computer hardware and peripherals

computer software



decorative hardware

e-commerce techniques

electrical inventions

electronic circuits

fabrics and fabric designs

food inventions

furniture design

games (board, box, and instructions)


Internet innovations


laser light shows


magic tricks or techniques

mechanical inventions

medical accessories and devices


musical instruments



recreational gear

sporting goods (designs and equipment)

What types of inventions can't be patented?

Many types of inventions are innovative and perhaps lucrative. You may seek to patent such inventions to prevent competitors from making and selling the sale product. Some types of inventions will not qualify for a patent, however, no matter how interesting or important they are.

For example, mathematical formulas, laws of nature, newly discovered substances that occur naturally in the world, and purely theoretical phenomena—such as a scientific principle like superconductivity—are considered unpatentable.

In addition, the following categories of inventions do not qualify for patents:

  • processes done entirely by human motor coordination, such as choreographed dance routines or a method for meditation
  • most protocols and methods used to perform surgery on humans
  • printed matter that has no unique physical shape or structure associated with it
  • unsafe new drugs
  • inventions useful only for illegal purposes, and
  • non-operable inventions, including "perpetual motion" machines (which are presumed to be non-operable because to operate they would have to violate certain bedrock scientific principles), and
  • creative content such as poetry, books, or music, which would be potentially subject to copyright protection rather than patent protection.

Can computer software be patented?

Yes. Even though you can't get a patent on a mathematical formula per se, you may be able to get protection for a specific application of a formula. Thus, software may qualify for a patent if the patent application produces a useful, concrete, and tangible result. For example, the U.S. Patent and Trademark Office (the federal agency that approves patents) will not issue a patent on the complex mathematical formulas used in space navigation, but will grant a patent for the software and machines that translate those equations and make the space shuttle go where it's supposed to.

What makes an invention "novel"?

In the context of a patent application, an invention is considered novel when it is different from all previous inventions (called "prior art") in one or more of its constituent elements. When deciding whether an invention is novel, the USPTO will consider all prior art that existed as of the date the inventor files a patent application on the invention.

An invention will fail the novelty test if it was described in a published document or put to public use prior to the date the patent application was filed. The only exception is if the actual inventor-applicant created the publication and it was made up to one year before the filing date, it will not bar the application. However, it is still unwise for an inventor to publish before filing since the inventor will lose foreign filing rights and another person may see the publication and file a separate application on it before the true inventor files, thus requiring an expensive and uncertain derivation proceeding.

When is an invention considered "nonobvious"?

To qualify for a patent, an invention must be nonobvious as well as novel. An invention is considered nonobvious if someone who is skilled in the particular field of the invention would view it as an unexpected or surprising development.

For example, let's say that in August 2023, Future Enterprises invents a portable, high-quality, virtual reality system that can be manufactured for under $100. A virtual reality engineer would most likely find this invention to be truly surprising and unexpected. Even though increased portability of a computer-based technology is always expected in the broad sense, the specific way in which the portability is accomplished by this invention would be a breakthrough in the field, and thus unobvious. Contrast this with a bicycle developer who uses a new, light-but-strong metal alloy to build his bicycles. Most people skilled in the art of bicycle manufacturing would consider the use of the new alloy in the bicycle to be obvious, given that lightness of weight is a desirable aspect of high-quality bicycles.

Knowing whether an invention will be considered nonobvious by the patent examiner is difficult because it is such a subjective exercise—what one patent examiner considers surprising, another may not. In addition, the examiner will usually be asked to make the nonobviousness determination well after the date of the invention, because of delays inherent in the patent process. The danger of this type of retroactive assessment is that the examiner may unconsciously be affected by the intervening technical improvements. To avoid this, the examiner generally relies only on the prior art references (documents describing previous inventions) that existed as of the date of invention.

As an example, assume that in 2020, Future Enterprises' application for a patent on the 2018 invention is being examined in the Patent and Trademark Office. Assume further that by 2020, you can find a portable virtual reality unit in any consumer electronics store for under $100. The patent examiner will have to go back to the time of the invention to fully appreciate how surprising and unexpected it was when it was first conceived, and ignore the fact that in 2020 the technology of the invention is already common.

What makes an invention "useful"?

An invention is useful if it provides some practical benefit, or helps people complete real world tasks. However, patents may be granted for inventions even if their use is merely humorous, such as a musical condom or a motorized spaghetti fork. An invention does not need to be "world changing" in order to clear the usefulness hurdle.

To fulfill this requirement, the invention must work, at least in theory. Thus, a new approach to manufacturing superconducting materials may qualify for a patent if it has a sound theoretical basis, even if it hasn't yet been shown to work in practice. But a new drug that has no theoretical basis and which has not yet been tested will not qualify for a patent.

Only a utility patent requires an invention to be useful: To qualify for a design or plant patent—the other two types of patents obtained in the U.S.—the inventor need not show utility.

How Broad Will My Patent Protection Be?

The scope of patent coverage—that is, how narrow or broad the claims—is determined by the novel features that distinguish an invention over prior art and provide new results that are different or unexpected enough to be considered nonobvious.

The fewer the novel features needed to distinguish an invention, the broader the scope of its coverage. Stated differently, if many new features are needed to distinguish the invention from prior art, the coverage is narrow and it's usually easier for a competitor to provide the same results without infringing.

Note that patent claims can be highly technical. You can view sample claims for common inventions, though the description of the claims can be far more intricate when the invention is, for example, a complex machine or pharmaceutical product. (Whether you decide to write your claims yourself or hire a patent attorney to assist you may depend on the complexity of your invention and your familiarity with technical writing.)

What Are Independent and Dependent Patent Claims?

Patents are usually made up of independent and dependent claims. One claim is stated as broadly as possible (the "independent claim") and then followed successively with narrower claims designed to specifically recite possible variations ("dependent claims").

The independent claim stands by itself, while a dependent claim always refers back and incorporates the language of another independent or dependent claim (see 35 U.S.C. § 112(3) and (4)). Below is an example of an independent and dependent claim for a golf club and bag security system (U.S. Pat. No. 5,973,596). In this example, the independent claim defines the elements of the golf bag security system and the dependent claim recites one aspect of it more specifically by stating that the alarm can be turned on and off by a separate device.

Independent Claim

  • 1. A golf bag security system for detecting movement of at least one golf club in a golf bag, the golf bag security system comprising:
    • a. a detection loop substantially arranged around the circumference of a golf bag
    • b. a loop oscillator circuit, connected to the detection loop
    • c. a control circuit, capable of detecting a change in inductance in the loop, identifying an alarm condition in response to the change of inductance, and
    • d. an alarm device responsive to the alarm condition.

Dependent Claim

  • 2. The system defined in claim 1, additionally comprising an arming device enabling or disabling the security system.

What Is the On-Sale Bar?

An invention can qualify for a patent under the rules stated above but be ineligible for patent protection if the invention has been "in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention." (35 U. S. C. §102(a)(1)). This limitation is called the "on-sale bar."

The on-sale bar is not limited to the widespread sale of an invention. Indeed, the U.S. Supreme Court has ruled that a commercial sale to a third party, even if the buyer is required to keep the invention confidential, might place the invention "on sale" under §102(a)(1). In a separate case, the Federal Circuit found that a firm offer for the sale of quantity of a chemical compound made the compound on-sale for §102(a)(1) purposes, despite the fact that the prospective buyer subsequently canceled the order (Merck & Cie v. Watson Labs., Inc., 822 F.3d 1347 (Fed. Cir. 2016)).

Inventors must keep the on-sale bar in mind and should avoid selling, licensing, or otherwise commercially offering their inventions to third parties prior to filing their patents.

Additional Help

For additional information on patents and the patenting process, see the patent section on Nolo's website. Nolo also offers helpful patent books, including Nolo's Patents for Beginners and Patent It Yourself, both by David Pressman.

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