Barber v. Thomas
The Supreme Court upheld the Bureau of Prisons' method of calculating good time credit, ruling that credit is earned based on time actually served in prison rather than the full sentence a judge handed down.
The decision means federal prisoners receive somewhat less credit than they would under a sentence-based calculation, affecting the release dates of tens of thousands of inmates nationwide.
“We conclude that the Bureau’s method reflects the most natural reading of the statute, and we reject petitioners’ legal challenge.”
The Court's core holding upholding the Bureau of Prisons' good time credit calculation.
How it got here: Federal trial courts rejected both prisoners' challenges to the credit calculation, the Ninth Circuit affirmed, and the Supreme Court agreed to hear the consolidated case.
The Case in Depth
What happened
Two federal prisoners, Michael Barber and Tahir Jihad-Black, serving long sentences, challenged how the Bureau of Prisons calculates "good time credit" — extra days off a sentence for good behavior. They argued the credit should be based on the full sentence a judge imposed, which would let them earn more days off, rather than on the shorter amount of time they would actually spend behind bars.
The question before the Court
Should federal prisoners' "good time" credit be calculated based on the sentence a judge imposed, or on the time they actually spend behind bars?
The Court's answer
The time actually served in prison — not the full sentence handed down by the judge. The Court ruled that the Bureau of Prisons' method of calculating good time credit is lawful because it tracks the statute's language requiring credit to be awarded "at the end of each year" based on behavior "during that year," which only makes sense if a prisoner has actually served that year.
This approach also fits the statute's purpose of rewarding good behavior with a limited, tailored incentive, rather than letting prisoners get credit for time they'll never spend behind bars. The Court rejected both the prisoners' broader reading and the dissent's alternative "administrative segment" approach, finding its own method the most natural and consistent with the statute's text and history.
Curious how the Court got there? See the step-by-step legal reasoning →
Why it matters
The ruling determines exactly how many days of early release nearly 200,000 federal prisoners can earn for good behavior. Under the Court's approach, well-behaved prisoners serve somewhat more time than they would under the prisoners' preferred calculation, directly affecting how long people stay in federal custody and how prisons plan for releases.
What changes now
This is a final merits decision resolving the legal question nationwide; the Ninth Circuit's judgment upholding the Bureau of Prisons' method is affirmed. The Bureau will continue calculating good time credit using its existing methodology for all eligible federal prisoners, and no further proceedings are required in this case. Prisoners seeking a different calculation method would need Congress to amend the statute.
What this does not decide
The Court did not decide whether the Bureau of Prisons' interpretation would be entitled to deference under Chevron, since it found the Bureau's reading was simply the most natural reading of the statute's text and purpose regardless of any deference question.
Concurrences and dissents
Dissent — Justice Kennedy
“To a prisoner, time behind bars is not some theoretical or mathematical concept. It is something real, even terrifying.”Kennedy's dissent emphasizing the human stakes behind the technical calculation dispute.
Justice Kennedy argued for a third interpretation under which a prisoner's 'term of imprisonment' is an administrative period of 365-day segments completed through a mix of actual time and earned credit, giving prisoners more credit than the majority's approach. He argued this reading treats the phrase consistently throughout the statute, better fits the statute's purpose of rewarding good behavior, and that the rule of lenity should favor prisoners given the statute's penal effect on nearly 200,000 inmates.
How the Court got there
The legal reasoning, step by step
- The Court read the statute's requirement that credit be awarded 'at the end of each year' based on behavior 'during that year' as tying credit to years actually spent in custody, since a prisoner cannot be evaluated for good behavior during a year he never serves.
- The Court compared the current law to the prior good-time system, which granted a credit deduction up front, subject to being taken away for misconduct; the shift to awarding credit only after a year of good behavior showed Congress meant to reward time already served rather than grant an advance entitlement.
- The Court looked to the purpose of the Sentencing Reform Act of 1984, which sought to make sentences determinate and predictable, with good time credit as the sole limited exception for rewarding actual good behavior in custody.
- Applying its method to the example of a ten-year sentence, the Court found that the prisoner would need to serve about 3,180 days and receive 470 days of credit, roughly 15% of time actually served, consistent with historical descriptions of the credit rate.
- The Court rejected the prisoners' proposed calculation because it would award credit for a year the prisoner might never actually spend in prison, and it rejected the dissent's proposed alternative because it required treating each year of the sentence as an elastic 'administrative segment' lasting fewer than 365 days, which the Court found inconsistent with the statute's plain language and would create administrability problems.
- Because the statute's text, structure, and purpose all pointed toward the Bureau's reading, the Court found no 'grievous ambiguity' that would trigger the rule of lenity in the prisoners' favor.