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When Does a Federal Sentence Officially Begin?

The statute ties commencement to being received in custody awaiting transportation, or to voluntary arrival — not simply to the day the judge speaks.

Post-sentencing • Custody transition Last reviewed: September 6, 2026

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Short answer

Under 18 U.S.C. section 3585(a), a federal sentence to a term of imprisonment commences on the date the person is received in custody awaiting transportation to the official detention facility at which the sentence is to be served, or arrives voluntarily at that facility to begin serving it. Sentencing day, designation and arrival are separate moments. Whether a particular set of facts meets that description is an individual legal question, and the Bureau of Prisons performs the computation.

Attorney review pending. This is general education, not legal advice.

Plain-English overview

The direct answer: under 18 U.S.C. § 3585(a), a federal sentence to a term of imprisonment commences on the date the person is received in custody awaiting transportation to the official detention facility at which the sentence is to be served, or arrives voluntarily at that facility to begin serving it.

That single sentence carries the whole rule, and it is not the same as the date of the sentencing hearing, the date of designation or the date of arrival at a particular prison. Whether a specific set of facts meets the statutory description is a legal question about an individual case, and CaseSteps does not answer it.

Commencement matters because other rules are measured from it. Prior-custody credit under § 3585(b) covers official detention before the sentence commences. First Step Act credit earning has its own rules and its own dates.

Why this matters

People frequently assume the sentence 'started' the day of the hearing, and then read every later record as an error. The statute asks a different question, and the Bureau of Prisons, not the court, makes the computation.

What the important terms mean

'Official detention facility at which the sentence is to be served' refers to where the sentence is served, which is the facility the Bureau of Prisons designates under 18 U.S.C. § 3621(b).

'Received in custody awaiting transportation' describes a status, not a place, and it is why a person can be at a detention center and still have a commenced sentence in some circumstances and not in others.

'Voluntary surrender' describes arriving at the designated facility on one's own to begin service. The Bureau of Prisons publishes general information about voluntary surrenders.

Ten things people treat as one thing

Sentence commencement

The date a federal term of imprisonment begins under 18 U.S.C. § 3585(a).

Prior-custody credit

Credit under § 3585(b) for time in official detention before the sentence commenced, computed by the Bureau of Prisons.

Good-conduct time

Up to 54 days per year of the sentence imposed under § 3624(b), based on the Bureau's determination about institutional conduct.

First Step Act Time Credits

A separate credit earned by eligible people for successfully completing assigned qualifying programming, with its own earning and application rules.

A projected release date

A forward-looking figure produced by the Bureau's computation that changes as records change.

A conditional or projected prerelease date

A different figure about community placement, not the end of the term of imprisonment.

Designation

The Bureau's decision under § 3621(b) about which facility a person is assigned to.

Transportation

The physical movement to that facility, which happens separately and on no published timetable.

Federal custody, state custody, primary jurisdiction

Which sovereign holds primary custodial jurisdiction is a separate question from who is physically holding someone on a given day.

A court recommendation and the BOP's authority

A sentencing court may recommend a facility or program; § 3621(b) leaves the designation decision with the Bureau of Prisons.

Common misunderstandings

  • "The sentence started the day of the hearing." Section 3585(a) does not say that. It describes being received in custody awaiting transportation, or voluntary arrival.
  • "Commencement and First Step Act credit earning are the same date." They are governed by different provisions, and sentencing alone does not necessarily start credit earning.
  • "Commencement decides prior-custody credit." It sets the boundary line for § 3585(b), but whether particular detention time qualifies is a separate Bureau of Prisons computation.
  • "The judge computes it." The Supreme Court held in United States v. Wilson that the computation is made after the defendant begins serving the sentence, by the Attorney General through the Bureau of Prisons.

Dated rule change — checked September 6, 2026

Through September 29, 2026, the existing version of 28 C.F.R. § 523.42(a) remains the currently effective regulatory text. It ties the start of First Step Act Time Credit earning to the date the person arrives, or voluntarily surrenders, at the designated Bureau of Prisons facility.

Effective September 30, 2026, revised § 523.42(a) states: “An eligible inmate begins earning FSA Time Credits after the inmate’s term of imprisonment commences.” The amendment removes the language that tied commencement to arrival or voluntary surrender at the designated Bureau facility.

This does not mean credits begin automatically merely because a sentence was imposed. The person must still be eligible and must successfully complete assigned, approved evidence-based recidivism-reduction programming or productive activities. The change does not promise retroactive credits and does not establish any individual release, placement or transition date. Implementation guidance and practices may change. Check the current regulation and current Bureau of Prisons guidance.

The same rule revises 28 C.F.R. § 523.44(a)(3). It states that the paragraph does not bar application of First Step Act Time Credits for a person serving a sentence imposed in a foreign country when the U.S. Parole Commission has determined an equivalent U.S. Code sentence under 18 U.S.C. § 4106A.

The document is an interim final rule and request for comments, published August 31, 2026 at 91 FR 55740, effective September 30, 2026. Comments are accepted through September 30, 2026. The Bureau invoked the Administrative Procedure Act’s good-cause provisions rather than using prior notice and comment.

This page describes a regulation that changes on September 30, 2026. Confirm the current regulation and Bureau of Prisons guidance before relying on it.

Whether the federal term of imprisonment has commenced is one input into when First Step Act credit earning can begin. That earning rule itself changes on September 30, 2026 under an interim final rule published August 31, 2026 at 91 FR 55740.

Commencement under § 3585(a) is unaffected by that rule. CaseSteps keeps the two questions on separate readings for that reason.

Records that may help clarify the issue

  • The judgment and commitment order.
  • The sentence-computation sheet, which shows the date the Bureau of Prisons treats as commencement.
  • Records of dates in official detention before that date.
  • Any voluntary-surrender instructions issued after sentencing.
  • Do not upload any of these records to CaseSteps, and do not type case numbers, dates or names anywhere on this site. Nothing here accepts files or keeps what you type.

Questions for appropriate Bureau of Prisons staff

  • Which document shows the commencement date the Bureau of Prisons is using?
  • What is the general process for obtaining a current copy of the sentence computation?
  • If the record appears to show something different from what I understood, how is an explanation requested?

Exactly where each statement above comes from — source checked: September 6, 2026

  • Commencement rule, quoted concept for concept: 18 U.S.C. § 3585(a), official U.S. Code text on GovInfo, read September 6, 2026.
  • The boundary between commencement and earlier detention: § 3585(b), which covers time 'prior to the date the sentence commences.'
  • The Bureau of Prisons performs the computation after service begins: United States v. Wilson, 503 U.S. 329, 333–337 (1992), official United States Reports text, read September 6, 2026.
  • The Bureau's own description of where computation is carried out: Bureau of Prisons Sentence Computations page, read September 6, 2026.
  • Program Statement 5880.28, Chapter 1 at page 1-12, restates § 3585(a) and addresses cases where a person is in exclusive federal custody at the time of sentencing. The document's change notices run through CN-7 (July 20, 1999) and it is listed as current on the Bureau's Sentence Computations page; parts of it describe organizational units that predate the Designation and Sentence Computation Center.

What CaseSteps cannot do

CaseSteps does not calculate prior-custody credit, good-conduct time, First Step Act Time Credits, a release date or any other figure.

CaseSteps does not predict a facility, a designation, a transfer date, a transportation route or how long anyone will remain in a detention facility, and it does not say whether sentences run concurrently or consecutively in a particular case or whether a detainer is valid.

The Bureau of Prisons performs the official sentence computation and holds the designation authority. Individual questions belong with appropriate Bureau staff and with qualified counsel.

Questions to discuss with counsel

  • In general terms, what does 18 U.S.C. § 3585(a) treat as the commencement of a federal sentence?
  • How is commencement different from prior-custody credit in my situation?
  • Does anything about my custody history make commencement a contested question?
  • Is the commencement date shown in Bureau records something the court can address, or only the Bureau?
  • What records should I preserve about dates in custody?

Official sources

This is general federal legal education, not legal advice. Procedures and outcomes depend on the facts, the controlling law, court orders and local practices. Confirm deadlines and decisions with qualified counsel.

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