What is the main difference between 5K1.1 and Rule 35(b)?

Timing. A 5K1.1 motion is filed before sentencing and asks the court to depart downward at the original sentencing hearing. A Rule 35(b) motion is filed after sentencing, typically within one year, and asks the court to reduce a sentence already imposed.

Can a defendant get both a 5K1.1 and a Rule 35(b) reduction?

Yes, in principle. A defendant may receive a downward departure at sentencing under 5K1.1 and later, if new substantial assistance emerges, file for a further reduction under Rule 35(b). Each motion requires a separate government filing and court decision.

Does Rule 35(b) have a time limit?

Yes. Under Fed. R. Crim. P. 35(b), the government must file the motion within one year after sentencing in most cases. The rule allows limited exceptions for assistance that was not known to the defendant or the government within that one-year window.

Does either motion guarantee a specific reduction?

No. Both 5K1.1 and Rule 35(b) give the court discretion over whether to grant the motion and by how much. The government recommends, but the court decides. Outcomes vary widely by case, jurisdiction, and judge.

Do both motions require the same standard of assistance?

Both require substantial assistance, but the exact standard and evaluation process can differ. 5K1.1 is evaluated at sentencing based on pre-sentencing cooperation. Rule 35(b) is evaluated after sentencing based on post-sentencing assistance or newly discovered pre-sentencing assistance that was not previously disclosed.

Can the court reduce a sentence below a mandatory minimum under either motion?

Only if the government also moves under 18 U.S.C. § 3553(e). That statute authorizes a sentence below a statutory mandatory minimum on the government's motion for substantial assistance. Without a § 3553(e) motion, the court cannot go below the statutory floor on this basis.

Does Federal Sentence Help help defendants decide whether to cooperate?

No. Federal Sentence Help is not a law firm and does not provide legal advice or recommendations about cooperation strategy. Decisions about whether to cooperate, what to disclose, and whether to seek a substantial-assistance motion are legal decisions that belong with the defendant and counsel.

Federal Sentence Planning Series

5K1 vs Rule 35(b): Pre-Sentencing and Post-Sentencing Cooperation Explained

Q: Which motion has a bigger impact on actual time in custody?

It depends on timing more than motion type. A 5K1.1 reduction applied early in a sentence may have more practical impact because it changes the starting point from which Good Conduct Time, First Step Act credits, and prerelease custody are calculated. A Rule 35(b) reduction granted late in a sentence may have less practical impact if the defendant is already close to RRC or home confinement.

Both 5K1.1 and Rule 35(b) reward substantial assistance, but the timing, filing requirements, and practical impact differ. This guide compares the two motions for defendants and families.

Published February 15, 2026

Two Motions, Same Goal, Different Timing

Both USSG § 5K1.1 and Fed. R. Crim. P. 35(b) allow a federal court to reduce a sentence when the defendant has provided substantial assistance in the investigation or prosecution of another person. The difference is when the motion is filed and when the reduction takes effect.

5K1.1: Before Sentencing

A 5K1.1 motion is filed by the government before the original sentencing hearing. The court considers the motion and, if it grants the departure, imposes a reduced sentence from the start. The defendant begins serving the already-reduced term.

Filed: before or at sentencing
Effect: the sentence imposed by the court is lower from day one
Standard: substantial assistance to authorities
Requires: government motion
Can also support: a motion under 18 U.S.C. § 3553(e) to go below a statutory mandatory minimum

Rule 35(b): After Sentencing

A Rule 35(b) motion is filed by the government after sentencing. The court amends the previously imposed sentence to a lower term. The defendant receives a reduced sentence while already serving time.

Filed: after sentencing, usually within one year
Effect: the already-imposed sentence is reduced by court order
Standard: substantial assistance to authorities
Requires: government motion
Time limit: generally one year, with narrow exceptions

Side-by-Side Comparison

Factor	5K1.1	Rule 35(b)
Timing	Before sentencing	After sentencing
Who files	Government	Government
What the court does	Departs below guideline range at sentencing	Reduces an already-imposed sentence
Time limit	None (must be before sentencing)	Generally one year from sentencing
Mandatory minimum	Requires separate § 3553(e) motion	Requires separate § 3553(e) motion
BOP computation	Computed from the reduced sentence at intake	Recomputed after the amended judgment

Why Timing Changes the Practical Impact

A 5K1.1 reduction is built into the sentence from day one. Good Conduct Time, First Step Act credits, RDAP, and RRC placement are all calculated from the lower number.

A Rule 35(b) reduction arrives after some or all of those mechanisms have already begun running. Depending on when the motion is granted, the defendant may already be close to prerelease custody. The reduction still lowers the sentence on paper, but the actual months saved inside a federal facility may be smaller than the numerical reduction suggests.

For a deeper walk-through of how post-sentencing reductions interact with BOP release planning, see Understanding Rule 35(b) and Federal Release Date Timing.

Can a Defendant Get Both?

Yes. A defendant may receive a 5K1.1 departure at sentencing and, if new substantial assistance emerges later, seek an additional reduction under Rule 35(b). Each motion is independent, requires a separate government filing, and receives its own judicial decision.

Records to Organize

Judgment and Commitment Order and any amended judgments
Plea agreement and any cooperation addendum
Presentence Investigation Report (PSR)
Sentence Monitoring Computation Data sheets
Documentation of programming, education, and work assignments
Any correspondence or filings related to the timing of a Rule 35(b) motion

Rule 35 questions people ask

What is Rule 35 in federal court?

Rule 35 of the Federal Rules of Criminal Procedure covers correcting or reducing a sentence after it is imposed. Subsection (a) allows correction of clear error within fourteen days. Subsection (b) allows a reduction for substantial assistance on the government's motion.

What is the difference between Rule 35(a) and Rule 35(b)?

Rule 35(a) fixes an arithmetical, technical, or other clear error within fourteen days of sentencing. Rule 35(b) is entirely different: it lets the court reduce a sentence for substantial assistance provided after sentencing, on a motion filed by the government.

How long does a Rule 35(b) motion take to be decided?

There is no set timeline. The court schedules the matter once the government files, and some districts rule on the papers while others hold a hearing. The larger delay is usually before filing, while the government evaluates whether the assistance was substantial.

Can a Rule 35(b) motion be filed more than a year after sentencing?

Sometimes. The general deadline is one year after sentencing, but the rule allows later filing in limited situations, such as information the defendant did not know was useful or assistance involving conduct discovered after the one-year period had already run.

Does a Rule 35 reduction change the release date automatically?

Not instantly. The court enters an amended judgment, and the Bureau of Prisons then recomputes the sentence with Good Conduct Time, First Step Act credits, and prerelease placement. The new projected release date appears after that recomputation is processed.

Educational purpose only. Federal Sentence Help is not a law firm. Nothing on this page constitutes legal advice.

Sources & References

Frequently Asked Questions

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Related Federal Sentence Help Resources

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