Prison Good Time Calculator Disclaimer

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Estimation Tool -- Not a Legal Document

The JailGuide prison good time calculator is an educational and planning tool. Results are estimates only and are not guaranteed to reflect the actual release date calculated by the Bureau of Prisons or any state Department of Corrections.

Nothing produced by this calculator constitutes legal advice. The only authoritative source for a federal inmate's release date is the BOP Inmate Locator. For state inmates, contact the state DOC directly or use the facility's case management system.

What the Calculator Cannot Account For

The calculator applies published good time rates to the sentence length entered. It does not have access to the inmate's individual record and cannot account for the following:

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Disciplinary Infractions

Good time credit can be reduced or revoked for disciplinary violations. In the federal system, a single serious infraction can result in the loss of up to 41 days of earned good time. The calculator assumes full good time is earned and maintained throughout the entire sentence. Any infraction will push the release date later than the calculator shows.

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Mandatory Minimum Sentences

Certain federal and state offenses carry mandatory minimum sentences that restrict how much good time credit can actually reduce the time served. Some offenses require a fixed percentage of the sentence to be served regardless of behavior. The calculator applies the standard good time rate without adjusting for mandatory minimums.

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Consecutive Sentences

If an inmate is serving multiple consecutive sentences, the calculator cannot aggregate them correctly. Good time on consecutive federal sentences is calculated on the total combined sentence, not each individually. For a rough estimate, add all sentence lengths together and enter the combined total -- but confirm the actual calculation with the facility case manager.

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Sentence Modifications and Appeals

Sentence reductions granted by a court, compassionate release motions, sentence modifications on appeal, or resentencing under retroactive guidelines amendments are not reflected in the calculator. If a sentence has been modified since the original judgment, enter the current sentence length, not the original.

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Halfway House and Home Confinement

Federal inmates are typically transferred to a Residential Reentry Center (halfway house) or home confinement before their official release date. This prerelease custody -- which can be up to 12 months under the Second Chance Act and additional time under the First Step Act -- effectively moves the day an inmate leaves federal prison earlier than the release date the calculator shows. The calculator shows the end of the custodial sentence, not the end of federal supervision.

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First Step Act Earned Time Credits

The First Step Act created Earned Time Credits (ETCs) that federal inmates can earn through participation in approved rehabilitative programming -- 10 to 15 days per 30 days of participation depending on risk level. ETCs can be applied to accelerate prerelease custody placement. The calculator does not include ETCs because eligibility and program availability vary by facility and inmate risk score.

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State Rule Changes

State good time statutes change. Legislatures pass truth-in-sentencing laws, expand or contract good time eligibility, and modify rates based on offense class. The calculator uses each state's current published rate as an approximation. If a state recently changed its good time law, the calculator may not yet reflect the update. Verify current rules with the state DOC for any sentence issued in the last 12 months.

Responsible Use of These Results

The calculator is built to help defendants, families and legal professionals get a working estimate of time to be served. Here is how to use it responsibly:

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Use it to understand roughly how long a sentence might last after good time -- as a planning tool for families making decisions about housing, employment and finances.

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Use it to compare how the RDAP reduction would affect a federal sentence -- running the calculation with and without RDAP helps evaluate whether pursuing RDAP eligibility is worth the effort.

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Use it as a starting point for conversations with an attorney or case manager about the actual projected release date.

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Do not represent the calculator result to a client, family member or employer as a guaranteed release date. It is an estimate with multiple sources of variation.

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Do not use it as the sole basis for legal strategy, plea negotiations, or financial commitments tied to a specific release date.

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Do not use it for sentences involving mandatory minimums, consecutive counts, or recent state law changes without first verifying the applicable rules.

For an authoritative federal release date, use the BOP Inmate Locator or contact the facility's case management office directly. For state sentences, use the state DOC inmate locator or JailGuide inmate search.

Calculator and Related Pages

Good Time Calculator

Use the calculator. Full federal and state good time explanation included.

Calculator Instructions

Field-by-field guide to entering your sentence correctly and reading the results.

Embed the Calculator

Free embed code for law firm websites, bail bond sites and legal resources.

RDAP Facilities and Eligibility

Full RDAP eligibility guide and list of all 53 federal facilities offering the program.

Federal Sentencing Guidelines

How federal sentences are calculated before good time is applied.

Find a Federal Attorney

Post a free legal question to a criminal defense attorney for an authoritative answer.

Disclaimer FAQ

Why is the result different from what the BOP says? +

The BOP calculates good time using the exact sentence imposed to the day, precise credit for time served, and the inmate's institutional record. The calculator uses rounded approximations. Minor differences are normal. Significant differences usually mean an infraction has been logged, a sentence modification has occurred, or the BOP is applying a mandatory minimum or consecutive sentence the calculator does not know about. The BOP figure is always the authoritative one.

Does the calculator account for mandatory minimums? +

No. Mandatory minimum sentences can restrict how much good time credit actually reduces time served. Some offenses require inmates to serve a fixed percentage of the sentence regardless of good behavior. The calculator applies the standard good time rate to whatever sentence length is entered, without adjusting for mandatory minimums. If a mandatory minimum applies, the actual release date may be later than the calculator shows.

What happens to good time if an inmate gets a disciplinary infraction? +

Disciplinary infractions can result in the loss of previously earned good time. In the federal system, a serious infraction can result in losing up to 41 days of good time per incident after a disciplinary hearing. Lost good time sometimes can be restored through subsequent good behavior, but there is no guarantee. The calculator assumes full good time is earned and maintained for the entire sentence -- any infraction will push the actual release date later than shown.

Does the calculator work for consecutive sentences? +

Not accurately. For a rough estimate, add all consecutive sentence lengths together and enter the combined total. But consecutive sentence good time calculations are more complex -- particularly in the federal system where good time is calculated on the total aggregated sentence. Confirm the actual calculation with the facility case manager or an attorney.

Is this a legal tool? +

No. Nothing produced by this calculator constitutes legal advice or a guarantee of any release date. It is an educational and planning tool. The only authoritative source for a federal inmate's release date is the BOP Inmate Locator or the facility's case management system. For state inmates, contact the state DOC. For legal advice about any specific sentence, consult a licensed criminal defense attorney.

Why do some states show a smaller reduction than expected? +

Truth-in-sentencing laws in some states require inmates to serve 85% or more of their sentence before becoming eligible for release. States including Arizona, Virginia and Wisconsin passed these laws in the 1990s -- often as a condition for receiving federal prison construction grants. In these states, good time credit has very limited effect on the actual release date compared to states that allow more generous reductions for nonviolent offenders.

Can I rely on this for financial or legal planning? +

Not as the sole basis for any significant decision. Use the calculator to get a working estimate, then verify the actual projected release date through the BOP or state DOC. For decisions involving employment, housing, child custody, financial arrangements or legal strategy that depend on a specific release date, always confirm with an authoritative source first.

Calculator Disclaimer