## Facts

- Inventors Gary R. Benson and Arthur C. Tabbot sought a patent for a method of converting binary-coded decimal (BCD) numerals into pure binary numerals for use on a general-purpose digital computer.
- The application described the invention as a programmed method for processing numerical data in a general-purpose computer.
- The challenged method claims were not limited to any particular technology, machine, hardware configuration, or end use, and purported to cover use on any general-purpose digital computer.
- A Patent Office examiner rejected the key method claims as unpatentable because they were directed to a mathematical expression; the Board of Patent Appeals affirmed.
- The Court of Customs and Patent Appeals reversed, holding the claims patentable as a “process.”
- The Acting Commissioner of Patents sought review, and the Supreme Court granted certiorari to decide whether the claims were a patentable “process” under the Patent Act.

## Issues

1. Whether a method claim that recites a computer-implemented procedure for converting BCD numerals to pure binary, without meaningful limitation to a specific apparatus or application, is a patentable “process” under 35 U.S.C. § 101.
2. Whether allowing such claims would impermissibly grant exclusive rights over a mathematical algorithm by effectively preempting its use.

## Decision

- The Supreme Court reversed the judgment of the Court of Customs and Patent Appeals.
- The Court held that the method claims were not a patentable “process” within the meaning of the Patent Act.
- The Court concluded the claims were directed to an algorithm—i.e., a series of mathematical calculations or mental steps—rather than a technological process tied to a specific machine or physical transformation.
- The Court reasoned that granting the patent would wholly preempt the underlying mathematical formula and, in practical effect, amount to a patent on the algorithm itself.

## Legal Principles

- Section 101’s broad categories of patentable subject matter are subject to implicit limits: laws of nature, mental processes, and abstract intellectual concepts are not patentable.
- A claim directed to a mathematical algorithm, without meaningful limitation to a particular apparatus or specific application, is not patent-eligible merely because it is intended to be performed on a computer.
- A claim that would “wholly pre-empt” a mathematical formula or algorithm is treated as an impermissible attempt to monopolize an abstract idea.
- Manipulation of numbers and mathematical calculations, standing alone, do not constitute a patentable process absent additional features that confine the claim to a patent-eligible application.

## Conclusion

The Court held that a broadly claimed, computer-implemented BCD-to-binary conversion method was unpatentable because it effectively claimed a mathematical algorithm itself, and permitting such claims would preempt a basic abstract idea outside the scope of § 101.


Gottschalk v. Benson, 409 U.S. 63 (1972)