How to use the prior custody credit calculator
Time spent locked up before sentencing counts toward a federal sentence. 18 U.S.C. 3585(b) gives a defendant credit for any time in official detention before the sentence commences, as long as that time has not already been credited against another sentence. Detention on the offense of conviction and detention on any other charge arising from the same conduct both qualify.
Two details matter. First, the Bureau of Prisons computes the credit after sentencing, not the judge, which the Supreme Court confirmed in United States v. Wilson, 503 U.S. 329 (1992). Second, 18 U.S.C. 3624(b) allows up to 54 days of good conduct time for each year of the sentence imposed, so a projected release date usually lands earlier than the raw term. Programs under the First Step Act can shift it further.
Treat the output as a planning estimate based on federal law as of September 2026. Actual credit depends on records the Bureau of Prisons holds, and state systems compute credit under their own statutes. This calculator is for reference only and is not legal advice. Consult a licensed attorney about your specific situation.
Frequently asked questions
Generally no. Section 3585(b) covers official detention, and conditions such as home confinement on release are usually not treated as detention.
The Bureau of Prisons computes credit and good conduct time after the judgment. Disputes go through the administrative remedy process before a court will review them.