Federal Sentence Planning Series
What Is a 5K1.1 Motion? Plain-Language Answers for Defendants and Families
Direct answers to the most common questions about 5K1.1 motions: what a 5K1.1 motion is, who files it, how much time it can take off, whether a judge has to grant it, how it differs from Rule 35(b), and what happens if the government does not file one.
Published September 2, 2026
The short answer
A 5K1.1 motion is a request filed by the federal prosecutor under USSG § 5K1.1 asking the sentencing judge to go below the otherwise applicable guideline range because the defendant gave substantial assistance in the investigation or prosecution of another person. Only the government can file it, and the judge decides whether to grant it and by how much.
For Education and Preparation
This guide is for education and preparation. It explains common federal sentence processes in plain language so individuals and families can better understand the timeline, organize important records, and prepare informed questions.
Federal Sentence Help is not a law firm and does not provide legal advice. Questions about your case, legal options, or strategy should be reviewed with an attorney or another qualified legal professional.
Questions people ask about 5K1.1 motions
What is a 5K1.1 motion?
A 5K1.1 motion is a request filed by the federal prosecutor under USSG Section 5K1.1 asking the sentencing judge to go below the otherwise applicable guideline range because the defendant gave substantial assistance in the investigation or prosecution of another person.
Who files a 5K1.1 motion?
Only the government files it. The guideline begins with the words upon motion of the government, so a defendant cannot file a 5K1.1 motion directly. Defense counsel can advocate for one, but the decision to file belongs to the prosecutor handling the case.
How much time does a 5K1.1 motion take off a federal sentence?
There is no fixed amount. The judge decides the size of the departure after weighing the value, truthfulness, extent, risk, and timeliness of the assistance. Reductions vary widely by case, district, and judge, and no percentage is guaranteed by the guideline.
Does a judge have to grant a 5K1.1 motion?
No. The government motion opens the door, but the court decides whether to depart and by how much. A judge may grant the motion in full, grant a smaller departure than the government suggests, or decline to depart based on the record.
What is the difference between a 5K1.1 motion and Rule 35(b)?
Timing. A 5K1.1 motion is filed before sentencing and shapes the sentence the judge imposes. A Rule 35(b) motion is filed after sentencing, usually within one year, and asks the court to reduce a sentence the defendant is already serving.
Can a 5K1.1 motion go below a mandatory minimum?
Only when the government also moves under 18 U.S.C. Section 3553(e). That statute gives the court limited authority to sentence below a statutory mandatory minimum for substantial assistance. Without it, a 5K1.1 departure cannot take the sentence beneath the statutory floor.
What happens if the government does not file a 5K1.1 motion?
The court cannot grant a substantial-assistance departure on its own. Courts review a refusal to file only in narrow circumstances, such as an unconstitutional motive or a breached agreement. Whether any challenge is available is a legal question for counsel to evaluate.
Is a 5K1.1 motion the same as a cooperation agreement?
No. A cooperation agreement describes what the parties agreed to do and what the government will consider. The 5K1.1 motion is the separate filing that actually asks the court for a reduction. An agreement can exist without a motion ever being filed.
Does a 5K1.1 reduction shorten time in BOP custody by the same amount?
Not necessarily. The Bureau of Prisons recomputes the sentence with Good Conduct Time, First Step Act earned time credits, RDAP, and prerelease placement. A shorter sentence changes the starting point, so the change in actual custody time may be larger or smaller.
Where to go next
- How a 5K1 motion works at sentencing, a longer walk-through of filing, timing, and what the judgment reflects
- USSG § 5K1.1 explained, including the five factors the court may weigh
- What substantial assistance means and how the government evaluates it
- 5K1.1 compared with Rule 35(b) for cooperation that continues after sentencing
- How the BOP computes the sentence that is actually served
Sources & References
Knowledge Ecosystem
Related Federal Sentence Help Resources
Each Federal Sentence Help resource is designed to fit alongside the others. Use the related tools, assessments, and guides below to keep building practical understanding of the process.
- Guide5K1 OverviewWhat 5K1 refers to and where it fits in federal sentencing.
- Guide5K1 MotionA longer walk-through of how the motion works at the sentencing hearing.
- GuideUSSG § 5K1.1 ExplainedThe text of the guideline and the five factors, in plain language.
- GuideSubstantial AssistanceWhat substantial assistance means and how the government evaluates it.
- Guide5K1 vs Rule 35(b)Side-by-side comparison of pre-sentencing and post-sentencing motions.
- ToolFederal Sentence CalculatorModel how a reduced sentence interacts with GCT, FSA credits, RDAP, and RRC placement.
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