This calculator provides estimates only. Results are not guaranteed. Many factors affect actual release dates. Read the full disclaimer • Calculator help and instructions
Federal Good Time Credit Explained
Federal good time credit is governed by 18 U.S.C. Section 3624(b). Under the First Step Act of 2018, federal inmates can earn up to 54 days of good time for every year of sentence imposed by the judge. This works out to roughly 15% off a federal sentence for inmates who maintain good behavior throughout.
Two key points most people get wrong: First, federal good time is calculated on the sentence imposed, not time served. A 60-month sentence earns good time based on 60 months, even though the inmate starts earning it from the first day. Second, the 54-day maximum is the ceiling -- it can be reduced or revoked for disciplinary infractions at any point during the sentence.
Federal Good Time Example
Sentence imposed
60 months (5 years)
Maximum good time (54 days × 5 years)
270 days (9 months)
Estimated time served
51 months
+ RDAP reduction if eligible
Up to 12 additional months off
Minimum possible time served (good time + RDAP)
~39 months
If you are a federal inmate with any history of substance abuse, RDAP is the single most powerful sentence reduction tool available. Under 18 U.S.C. Section 3621(e), eligible nonviolent offenders who complete RDAP can receive up to 12 months off their sentence in addition to good time -- separate calculations that stack on top of each other.
First Step Act Earned Time Credits
The First Step Act of 2018 created a second type of federal sentence reduction separate from good time: Earned Time Credits (ETCs). Federal inmates can earn 10 days of ETC for every 30 days of successful participation in approved Evidence-Based Recidivism Reduction (EBRR) programs or Productive Activities (PAs). Inmates at minimum or low risk of recidivism can earn 15 days per 30 days.
Earned Time Credits can be applied toward early placement in prerelease custody -- halfway house or home confinement -- rather than directly reducing the sentence. The calculator above does not currently include ETCs because eligibility and programming availability vary significantly by facility. Ask your case manager about which programs at your facility qualify for ETC.
State Good Time Credit -- How It Differs
State good time rules vary dramatically. There is no uniform system -- each state legislature sets its own rules, and many states have changed their laws multiple times. The calculator accounts for each state individually. Here is how the major categories break down:
Most Generous
California, Colorado, Illinois, New York, Oregon
Up to 33-50% reduction for nonviolent offenders. California allows up to half time off for nonviolent crimes.
Moderate
Florida, Georgia, Michigan, Ohio, Texas
Typically 20-33% reduction depending on offense class. Many states have separate rules for violent vs. nonviolent offenders.
Truth in Sentencing
Arizona, Virginia, Wisconsin, Mississippi (violent offenses)
Requires inmates to serve 85% or more of their sentence. Very limited good time available, primarily for violent offenders.
State good time rules are subject to change by the legislature at any time. Always verify current rules with the state DOC, the inmate's attorney, or the facility case manager. The rates in the calculator are approximate and are updated periodically but should not be relied upon as legal advice.
Related Tools and Resources
Good Time Calculator FAQ
How much good time credit do federal inmates receive? +
Under the First Step Act, federal inmates can earn up to 54 days of good time credit for every year of sentence imposed. This is approximately 15% off the sentence. Good time is calculated on the sentence imposed by the judge -- not time actually served. A 60-month sentence earns up to 270 days of good time, reducing actual time served to roughly 51 months.
Does good time credit apply to all federal inmates? +
Federal good time under 18 U.S.C. Section 3624(b) applies to all federal inmates serving sentences of more than one year. It is earned automatically through good behavior and is not discretionary -- though it can be reduced or taken away entirely for disciplinary infractions. There is no application required; the BOP tracks it automatically.
What is the difference between good time and RDAP reduction? +
Good time is earned automatically by all federal inmates through good behavior. The RDAP reduction under 18 U.S.C. Section 3621(e) is a separate benefit of up to 12 additional months for eligible nonviolent inmates who complete the Residential Drug Abuse Program. Both reductions apply independently and can be stacked. Good time reduces the sentence by ~15% and RDAP can cut up to another 12 months on top of that.
How does state good time differ from federal? +
State good time rules vary significantly by state and are set by each state legislature. Some states allow up to 50% off for nonviolent offenders. Truth-in-sentencing states like Arizona and Virginia require inmates to serve 85% or more of their sentence regardless of behavior. Many states have different rules for violent vs. nonviolent offenses. The calculator uses each state's current approximate rate -- check with the state DOC for the exact rules in your case.
Can good time credit be taken away? +
Yes. Good time can be reduced or revoked for disciplinary infractions including fighting, possession of contraband, threatening staff, or failure to comply with facility rules. The BOP holds a disciplinary hearing for serious infractions and can sanction the loss of up to 41 days of good time per violation. This is why the calculator is an estimate -- the actual release date depends on the inmate maintaining clean conduct throughout the sentence.
What is the First Step Act and how does it affect good time? +
The First Step Act of 2018 increased the maximum federal good time credit from 47 days per year to 54 days per year of sentence imposed. It also created the Earned Time Credits program, allowing federal inmates to earn additional days toward prerelease custody by participating in approved rehabilitative programming. Inmates at minimum or low risk of recidivism can earn 15 days of ETC per 30 days of participation rather than the standard 10 days.
Is the calculator accurate? +
The calculator provides a good-faith estimate based on current good time statutes and BOP policy. It does not account for disciplinary sanctions, parole or supervised release decisions, sentence modifications, consecutive sentences, Earned Time Credits under the First Step Act, or halfway house and home confinement time. Use it as a planning tool to understand approximately how much time will be served -- not as a guaranteed release date. See the full
calculator disclaimer for details.