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SENTENCE CALCULATOR

Federal Prison Sentence Calculator

Estimate your actual time served with First Step Act credits, Good Conduct Time, RDAP, and more.

About This Calculator

Understanding how long you'll actually serve in federal prison requires more than just looking at your sentence. The Bureau of Prisons (BOP) applies multiple credit programs that can significantly reduce your time in federal prison.

Good Conduct Time (GCT) provides 54 days off per year for sentences over 12 months. First Step Act credits can reduce your sentence by up to 365 days through program participation. RDAP (Residential Drug Abuse Program) offers an additional 6-12 months off for qualifying individuals. Solid release planning can lead to up to 12 months in a halfway house or home confinement.

Enter your sentence below to see your estimated time in facility and projected release date. This calculator uses the same 30-day BOP cycle methodology used by the federal prison system.

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Enter Your Details

Surrender Date

Sentence Length

View disqualifying offenses

Pre-trial detention or jail time. Default 1 day for guilty plea.

0 mo6 mo12 mo

Halfway house or home confinement under the Second Chance Act (up to 12 months).

RDAP Sentence Reduction (up to 12 months)

The Residential Drug Abuse Program can reduce your sentence by 6–12 months depending on sentence length. Learn about RDAP eligibility

Your Sentence Estimate

Estimated time in federal prison

0 months

That's 0 days off your 0 months sentence

Enter a surrender date to see projected calendar dates

Understand how good time credits and RDAP affect your sentence. Learn more

Credit Breakdown

How your time is calculated

Original Sentence0 months
Time Already Served(credited)
-1 day
Good Conduct Time(not eligible)
-0 months
First Step Act Credits(not eligible)
-0 days
Conditional Release Date From Federal Prison (CRD)0 months

Important Notes

  • •Sentences of 12 months or less are not eligible for Good Conduct Time, but ARE eligible for First Step Act credits.

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All dates shown are estimates based on statutory rules and available inputs. Final placement and release decisions are made by the Bureau of Prisons.

This calculator provides estimates only. Have questions?
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Actual time served depends on behavior, program participation, case manager decisions, and BOP policies. If we're on the phone, please call back.

How Long Is Your Sentence in Real Time?

Federal Good Time Credit Chart

Sentence (months)Good time credit (days)Actual time served (approx.)
12 months54 days~10 months
18 months81 days~15 months
24 months108 days~20 months
30 months135 days~26 months
36 months162 days~31 months
48 months216 days~41 months
60 months270 days~51 months
84 months378 days~72 months
120 months540 days~102 months
180 months810 days~153 months
240 months1,080 days~204 months

Good conduct time applies to sentences over 1 year. Actual release dates depend on additional factors including First Step Act credits and RDAP completion.

How Federal Prison Sentence Credits Work

Good Conduct Time (GCT)

Good Conduct Time awards 54 days of credit per year served for federal sentences longer than 12 months. GCT is applied automatically — you don't need to apply or enroll — but it can be reduced or revoked if you receive disciplinary infractions while incarcerated. For most people, GCT alone reduces a sentence by roughly 15%. Learn more about early release from federal prison.

First Step Act Time Credits

Under the First Step Act, eligible individuals earn 10 to 15 days of credit for every 30-day cycle of approved programming or productive activities. The earning rate increases after an initial assessment period, and credits are capped at 365 days toward your release date — any surplus advances your community placement date instead. Certain offenses disqualify people from earning these credits entirely. See our full First Step Act time credits guide.

RDAP Sentence Reduction

The Residential Drug Abuse Program (RDAP) is a 9-month intensive treatment program that can reduce an eligible sentence by up to 12 months upon successful completion. To qualify, you must have a documented substance use disorder, a sentence of at least 24 months, and no disqualifying convictions such as certain violent or weapons offenses. Review the RDAP eligibility requirements.

Halfway House and Home Confinement

Under the Second Chance Act, the BOP can place individuals in a halfway house or on home confinement for up to 12 months before their release date. This does not shorten your overall sentence — it changes where you serve the final portion, transitioning you from a federal facility to community-based custody. Learn more about home confinement placement and eligibility.

How This Calculator Works

This calculator uses the same 30-day BOP cycle methodology that the federal prison system uses to compute earned credits. It applies Good Conduct Time, First Step Act credits, and RDAP reductions in the same order and priority as the Bureau of Prisons, including the iterative convergence process for FSA earning windows. Results are estimates based on current BOP policy and should not be treated as legal advice — actual release dates depend on individual eligibility, disciplinary history, and administrative decisions.

Frequently Asked Questions

This calculator provides estimates based on federal credit programs and common BOP practices, but actual release dates can vary based on eligibility, disciplinary history, and policy changes. For comparison, see our release date calculator.

You'll need your sentence length, surrender date (or start date), and whether you may qualify for credits like Good Conduct Time, First Step Act credits, or RDAP. Your pre-sentence investigation report (PSR) often contains the key details that affect eligibility.

Good Conduct Time (GCT) can reduce a federal sentence by up to 54 days per year for eligible sentences over 12 months, but credits can be reduced or lost if disciplinary infractions occur. Learn more about early release from federal prison.

First Step Act credits may be earned through approved programs and productive activities, and eligible people can earn 10–15 days per 30 days of participation depending on BOP rules. See our full First Step Act time credits guide.

The Residential Drug Abuse Program (RDAP) may reduce an eligible sentence by up to 12 months, but qualification depends on documented substance use history and BOP criteria. See RDAP eligibility requirements.

Home confinement and halfway house placement usually don't reduce your sentence length — they change where you serve the final portion of your sentence. Learn more about home confinement and halfway house and home confinement BOP placement rules.

Yes. Good Conduct Time and First Step Act credits can be reduced or revoked due to disciplinary infractions or loss of eligibility. See common disciplinary infractions and how they affect time credits.

Yes — this calculator is based on BOP credit programs that apply across many federal offenses, but some convictions can limit eligibility for RDAP or certain First Step Act benefits. For context, see white collar life in federal prison.

Yes, as long as you enter accurate inputs (sentence length, dates, and credit assumptions), but results are still estimates and may differ from official BOP calculations. You can also use our projected release tool.

The most important preparation is having a release plan and avoiding disciplinary issues. Start with our federal prison self-surrender guide, then begin documenting your journey at PrisonProfessors.org.