What is the difference between claiming priority and claiming benefit in patent applications?

Claiming priority and claiming benefit are two different mechanisms in patent law, though both can affect the effective filing date of a patent application:

1. Claiming Priority:
   • Typically refers to claiming the right of priority to a foreign application under 35 U.S.C. 119(a)-(d) and (f)
   • Also includes priority claims to provisional applications under 35 U.S.C. 119(e)
   • Governed by 37 CFR 1.55 for foreign priority claims
2. Claiming Benefit:
   • Refers to claiming the benefit of an earlier filing date of a U.S. application under 35 U.S.C. 120, 121, 365(c), or 386(c)
   • Typically used for continuation, divisional, or continuation-in-part applications
   • Governed by 37 CFR 1.78

The MPEP discusses both types of claims: “Under certain conditions and on fulfilling certain requirements, a later-filed application for patent filed in the United States may claim the benefit of, or priority to, a prior application filed in the United States (see 35 U.S.C. 119(e), 120, 121, 365(c), and 386(c); see also 37 CFR 1.78) or in a foreign country (see 35 U.S.C. 119(a)-(d) and (f), 365(a) and (b), and 386(a) and (b); see also 37 CFR 1.55).”