--- title: "18 U.S.C. § 3624(b) — Good Conduct Time" module_id: "MOD-GOOD-CONDUCT-TIME" url: "https://jason93.com/legal/federal-process/modules/80-sentence-execution-and-bop/good-conduct-time/" current_through: "2026-08-26" legal_review: "2026-08-24" links_checked: "2026-10-15" links_available: 5 links_checked_count: 5 license: "CC BY 4.0" --- # 18 U.S.C. § 3624(b) — Good Conduct Time ## Verification boundary This module verifies the current nationwide statutory and regulatory calculation structure for good-conduct time (GCT), the First Step Act change, and the historical boundary of *Barber v. Thomas*. It does not verify a particular prisoner's computation, disciplinary loss, restoration, administrative-exhaustion history, or § 2241 remedy. ## Current statutory rule Section 3624(a) directs the Bureau of Prisons to release a prisoner when the term of imprisonment expires, less credit toward service of the sentence provided by § 3624(b). [18 U.S.C. § 3624(a)](https://www.govinfo.gov/link/uscode/18/3624) A prisoner serving more than one year, other than a life term, may receive up to fifty-four days of GCT for each year of the sentence imposed by the court, subject to the Bureau's determination of exemplary compliance with institutional disciplinary regulations. [18 U.S.C. § 3624(b)(1)](https://www.govinfo.gov/link/uscode/18/3624) “Up to” is consequential: the statute does not promise the maximum award. A sentence of one year or less and a life term fall outside this authorization. If the Bureau determines that the prisoner did not satisfactorily comply during the relevant year, the prisoner receives no GCT or a lesser amount the Bureau determines appropriate; the Bureau also must consider high-school-diploma progress, and credit not earned may not later be granted. [18 U.S.C. § 3624(b)(1)](https://www.govinfo.gov/link/uscode/18/3624) Subject to § 3624(b)(2), the statute directs that credit for the last year of a term be credited on the first day of the last year. [18 U.S.C. § 3624(b)(1)](https://www.govinfo.gov/link/uscode/18/3624) That timing sentence does not eliminate partial-final-year proration. The current regulation separately addresses both proration and the anniversary-period mechanics. GCT awarded under § 3624(b) after enactment of the Prison Litigation Reform Act vests on the date the prisoner is released from custody. [18 U.S.C. § 3624(b)(2)](https://www.govinfo.gov/link/uscode/18/3624) ## Current regulatory calculation For offenses committed on or after November 1, 1987, 28 C.F.R. § 523.20(b)(1) directs the Bureau to project the maximum possible GCT from the imposed sentence while recognizing that the projected release date can change during incarceration. [28 C.F.R. § 523.20(b)(1)](https://www.govinfo.gov/content/pkg/CFR-2025-title28-vol2/pdf/CFR-2025-title28-vol2-sec523-30.pdf) The Bureau awards prorated GCT for a partial final year of the sentence imposed. [28 C.F.R. § 523.20(b)(2)](https://www.govinfo.gov/content/pkg/CFR-2025-title28-vol2/pdf/CFR-2025-title28-vol2-sec523-30.pdf) This corrects the legacy statement that the First Step Act's timing change replaced proration. The 2022 final rule expressly chose proration for a partial final year. Under the regulation, an inmate may receive up to fifty-four days on each anniversary date; last-year credit is awarded after the final anniversary period unless the final year is complete, in which case it is awarded on the first day of that final anniversary period. [28 C.F.R. § 523.20(b)(3)](https://www.govinfo.gov/content/pkg/CFR-2025-title28-vol2/pdf/CFR-2025-title28-vol2-sec523-30.pdf) For an offense committed on or after April 26, 1996, the regulation sets a maximum of fifty-four days per imposed-sentence year when the literacy condition is met and forty-two days when it is not, subject to the regulation's final-removal-order exception. [28 C.F.R. § 523.20(d)(2)–(3)](https://www.govinfo.gov/content/pkg/CFR-2025-title28-vol2/pdf/CFR-2025-title28-vol2-sec523-30.pdf) The regulation permits GCT reduction for qualifying disciplinary sanctions or failure to comply with applicable literacy requirements. [28 C.F.R. § 523.20(a)](https://www.govinfo.gov/content/pkg/CFR-2025-title28-vol2/pdf/CFR-2025-title28-vol2-sec523-30.pdf) Actual loss, disallowance, forfeiture, and restoration require the disciplinary record, the offense-date branch, and the current rules in Parts 541 and 544; they are not calculated by this module. ## First Step Act change and historical rule The First Step Act changed GCT from a time-served calculation to a sentence-imposed calculation, made the amendment applicable to offenses committed before, on, or after enactment except offenses before November 1, 1987, and the change took effect when the risk-and-needs system was released on July 19, 2019. [First Step Act § 102(b), 132 Stat. 5210–11](https://www.govinfo.gov/content/pkg/PLAW-115publ391/pdf/PLAW-115publ391.pdf); [BOP First Step Act FAQ](https://www.bop.gov/inmates/fsa/faq.jsp) The correct dividing fact is therefore amendment coverage—especially offense date—not whether a particular day of the sentence was served before July 19, 2019. Covered computations were recalculated under the amended rule. Barber v. Thomas upheld the Bureau's time-served method under the pre-First Step Act text, but the First Step Act superseded that calculation rule for covered current sentences. [*Barber v. Thomas*, 560 U.S. 474, 476–87 (2010)](https://www.govinfo.gov/content/pkg/USREPORTS-560/pdf/USREPORTS-560-474.pdf); [First Step Act § 102(b)](https://www.govinfo.gov/content/pkg/PLAW-115publ391/pdf/PLAW-115publ391.pdf) Good-conduct-time credit under § 3624(b) is distinct from First Step Act time credits earned through recidivism-reduction programs and applied under §§ 3632(d)(4) and 3624(g). [Good Conduct Time Credit Under the First Step Act, 87 Fed. Reg. 7938, 7941 (Feb. 11, 2022)](https://www.federalregister.gov/documents/2022/02/11/2022-02876/good-conduct-time-credit-under-the-first-step-act) ## Computation audit checklist 1. Obtain the judgment, statement of reasons if relevant, and the Bureau sentence-computation sheet. 2. Record the offense date, imposed term, and whether the sentence is life or no more than one year. 3. Separate GCT from prior-custody credit, RDAP reduction, First Step Act time credits, and prerelease-placement dates. 4. Check the maximum projection, each disciplinary adjustment, literacy status, anniversary periods, and partial-final-year proration. 5. Do not switch to the historical *Barber* formula merely because some custody occurred before July 19, 2019. 6. Preserve the Bureau's actual calculation and administrative record before researching exhaustion and a possible § 2241 challenge. ## Decision path ```mermaid flowchart TD A["GCT computation question"] --> B{"Offense on or after Nov. 1, 1987?"} B -->|"No"| C["Current § 523.20 branch does not apply; research old-law credit"] B -->|"Yes"| D{"Term more than one year and not life?"} D -->|"No"| E["Outside § 3624(b)(1) GCT authorization"] D -->|"Yes"| F["Project up to 54 days per imposed-sentence year"] F --> G["Prorate partial final year"] G --> H["Apply conduct, literacy, and offense-date rules"] H --> I["Compare Bureau computation and records"] ``` ## Matters not yet verified in this module - Old-law credit for offenses before November 1, 1987 and D.C. Code credit. - Particular disciplinary procedures, restoration standards, and due-process claims. - Administrative-remedy deadlines, exceptions to exhaustion, proper § 2241 respondent, venue, and available relief. - Interaction with prior-custody credit, aggregated sentences, RDAP, and First Step Act time credits in a particular computation. Those matters remain open in `data/coverage_matrix.yaml`; this bounded correction does not validate the legacy file as a whole. ## Authorities - [18 U.S.C. § 3624](https://jason93.com/legal/federal-process/authorities/AUTH-USC-18-3624.md) · official source: https://www.govinfo.gov/link/uscode/18/3624 - [28 C.F.R. § 523.20](https://jason93.com/legal/federal-process/authorities/AUTH-CFR-28-523-20.md) · official source: https://www.govinfo.gov/content/pkg/CFR-2025-title28-vol2/pdf/CFR-2025-title28-vol2-sec523-30.pdf - [First Step Act of 2018, Pub. L. No. 115-391, § 102(b), 132 Stat. 5194, 5210–11](https://jason93.com/legal/federal-process/authorities/AUTH-PL-115-391-SEC-102-B.md) · official source: https://www.govinfo.gov/content/pkg/PLAW-115publ391/pdf/PLAW-115publ391.pdf - [Barber v. Thomas, 560 U.S. 474 (2010)](https://jason93.com/legal/federal-process/authorities/AUTH-SCOTUS-BARBER-560-US-474.md) · official source: https://www.govinfo.gov/content/pkg/USREPORTS-560/pdf/USREPORTS-560-474.pdf - [Federal Bureau of Prisons, First Step Act Frequently Asked Questions — Good Conduct Time](https://jason93.com/legal/federal-process/authorities/AUTH-BOP-FSA-GCT-FAQ.md) · official source: https://www.bop.gov/inmates/fsa/faq.jsp