18 USC 3624: Good Conduct Time, FSA Credits, Halfway House

A federal release date under 18 U.S.C. 3624 is not a single number printed on a judgment. The Bureau of Prisons takes the sentence the judge imposed, subtracts credit for time already spent in official custody, subtracts good conduct time earned year by year, and subtracts First Step Act earned time credits for those who qualify. For most inmates, the final months are then served in a halfway house or on home confinement rather than inside a federal facility. Each of those steps has its own rules, and small details can move the date by months.

The Starting Point: Sentence Imposed

Under 18 U.S.C. 3624(a), the BOP must release a prisoner on the date the sentence expires, less any credits earned. If that date lands on a Saturday, Sunday, or federal holiday, the BOP can release the person on the last preceding business day.¹

The raw end-of-sentence date rarely survives contact with the credit calculations that follow. Everything else in the process pulls that date earlier.

Credit for Time Already Served

Before the BOP even applies good conduct time, it looks backward. Under 18 U.S.C. 3585(b), a defendant gets credit for any time spent in official detention before the sentence began, so long as that time has not already been credited against a different sentence.² That covers pretrial detention, time held on a writ, and similar custody tied to the same offense.

The BOP performs this calculation, not the sentencing judge. Disputes are common, and prisoners sometimes have to go to court to correct a miscalculated credit.

Concurrent or Consecutive Sentences

When a defendant has more than one sentence, whether they stack or overlap changes the calculation entirely. Under 18 U.S.C. 3584, multiple sentences imposed at the same hearing run concurrently unless the court says otherwise. Sentences imposed at different times run consecutively by default unless the court expressly orders them to run at the same time.³

That default trips up defendants who catch a new charge while already serving time. Unless the judgment says concurrent, the new sentence begins only after the current one ends.

Good Conduct Time

Good conduct time is the largest routine reduction. Under 18 U.S.C. 3624(b), a prisoner serving a sentence of more than one year can earn up to 54 days of credit for each year of the sentence imposed by the court, provided the BOP determines the prisoner displayed “exemplary compliance” with institutional disciplinary rules during that year.¹ Life sentences and sentences of a year or less do not qualify.

The First Step Act of 2018 changed the base for this calculation. Before the Act, the BOP calculated good conduct time against time actually served, a method the Supreme Court upheld in Barber v. Thomas as the most natural reading of the statute at the time.⁴ The Act rewrote the formula to run against the sentence imposed, which yields more credit days. The change took effect on July 19, 2019.⁵

The credit is not automatic. Disciplinary violations, including violence or possessing contraband, can lead to lost good conduct time, and lost time can push a release date back significantly. BOP staff review each inmate’s record periodically to decide whether the exemplary-compliance standard was met.

First Step Act Earned Time Credits

Earned time credits are a separate track, created by 18 U.S.C. 3632 as part of the First Step Act. These credits are awarded for successful participation in approved recidivism reduction programs and productive activities.

The rate depends on risk classification:

Standard rate: 10 days of credit for every 30 days of successful participation.
Enhanced rate: 15 days per 30 days for inmates classified as minimum or low risk who have not increased their recidivism risk over two consecutive assessments.⁶

Eligibility is limited. The statute lists dozens of disqualifying offenses, including many sex offenses, terrorism-related crimes, and certain violent offenses. Inmates subject to a final order of deportation can earn the credits but cannot apply them toward earlier release.⁶

Once earned time credits equal the time remaining on the sentence, 18 U.S.C. 3624(g) directs the BOP to transfer the prisoner into prerelease custody or onto supervised release, provided additional risk-level requirements are met. Prerelease home confinement under this pathway requires 24-hour electronic monitoring, and the prisoner may leave home only for approved purposes such as work, programming, medical treatment, or religious activities.¹

The Final Months: Halfway House or Home Confinement

Even without earned time credits, 18 U.S.C. 3624(c) directs the BOP to place inmates in transitional settings for a portion of the final part of the sentence, up to a maximum of 12 months. Placement is typically at a residential reentry center, commonly called a halfway house, or on home confinement.¹

The statute says “to the extent practicable,” which leaves the BOP significant discretion. Case managers weigh the offense, institutional conduct, release plans, and available bed space. Inmates with stable employment prospects, family support, and clean discipline tend to receive longer transitional placements. Serious disciplinary issues or certain convictions can result in a direct release from the federal facility with no halfway house stop.

Compassionate Release and Supervised Release: What They Are Not

Two things often get folded into questions about release-date calculation, but neither actually changes how the BOP computes the date under 3624.

Compassionate release is a court-ordered sentence reduction under 18 U.S.C. 3582(c)(1)(A) for “extraordinary and compelling reasons,” such as terminal illness, serious medical decline, qualifying age with substantial time served, or the death or incapacitation of a caregiver for a minor child. The prisoner must first ask the BOP to file a motion and either exhaust administrative appeals or wait 30 days after the warden receives the request before filing directly in court.⁷ It is a separate motion, not a credit built into the release date.

Supervised release is also separate. It is not parole and it does not shorten the prison term. It begins the day the person leaves BOP custody and runs as a period of court oversight afterward, with a length tied to the offense class: up to five years for Class A or B felonies, up to three years for Class C or D, and up to one year for Class E felonies and misdemeanors, with longer or lifetime terms possible for certain sex offenses and terrorism-related convictions.⁸ One interaction with the release calculation is worth knowing: under 18 U.S.C. 3624(e), the supervised release clock stops running during any period the person is imprisoned for 30 or more consecutive days on a federal, state, or local conviction. Shorter jail stays do not pause it.¹

Putting the pieces together, a federal release date starts with what the judge imposed and moves earlier through pretrial credit, good conduct time, and, for those who qualify, First Step Act earned time credits, with the final months typically served outside a federal facility. Each subtraction has its own eligibility rules, and disciplinary history can undo them. Anyone tracking a specific date should confirm the current BOP computation in writing, because that is the document that governs when the gate opens.

1
Office of the Law Revision Counsel. 18 USC 3624 – Release of a Prisoner
2
Office of the Law Revision Counsel. 18 USC 3585 – Calculation of a Term of Imprisonment
3
Office of the Law Revision Counsel. 18 USC 3584 – Multiple Sentences of Imprisonment
4
Legal Information Institute. Barber v. Thomas, No. 09-5201
5
Federal Register. Good Conduct Time Credit Under the First Step Act
6
Office of the Law Revision Counsel. 18 USC 3632 – Development of Risk and Needs Assessment System
7
Office of the Law Revision Counsel. 18 USC 3582 – Imposition of a Sentence of Imprisonment
8
Office of the Law Revision Counsel. 18 USC 3583 – Inclusion of a Term of Supervised Release After Imprisonment