Federal sentencing
Federal Mandatory Minimum Sentences: How They Work
A mandatory minimum is the shortest prison term a federal statute allows. The judge cannot go below it except in a few narrow situations set by law.
By Brandon Sample · Updated · Filed under Sentencing articles
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A mandatory minimum sentence is the shortest prison term a federal statute allows for a crime. When one applies, the judge cannot impose less, even if the Sentencing Guidelines or the judge's own view would point lower. Congress allows only a few exceptions: the safety valve in some drug cases, and government motions for substantial assistance.
This page explains the federal rules only. It is general information, not legal advice for your case.
What is a federal mandatory minimum?
Many federal statutes set a range of punishment: a maximum, and sometimes a minimum. The drug statute, for example, says the sentence "may not be less than 10 years or more than life" for certain amounts (21 U.S.C. § 841(b)(1)(A)). That floor is the mandatory minimum.
What triggers a minimum depends on the statute. Common triggers are:
- the type and amount of drugs;
- a gun used or carried in connection with another crime;
- certain prior convictions;
- the nature of the offense, as with child-exploitation crimes.
What are the most common federal mandatory minimums?
Drug quantity minimums
For drug trafficking under 21 U.S.C. § 841, the amount of a "mixture or substance containing a detectable amount" of the drug sets the minimum. A conspiracy or attempt under 21 U.S.C. § 846 carries the same penalties.
| Drug | 5-year minimum, § 841(b)(1)(B) | 10-year minimum, § 841(b)(1)(A) |
|---|---|---|
| Heroin (mixture) | 100 grams or more | 1 kilogram or more |
| Cocaine (mixture) | 500 grams or more | 5 kilograms or more |
| Cocaine base, "crack" (mixture) | 28 grams or more | 280 grams or more |
| Fentanyl (mixture) | 40 grams or more | 400 grams or more |
| Fentanyl analogue or fentanyl-related substance (mixture) | 10 grams or more | 100 grams or more |
| Methamphetamine (pure) | 5 grams or more | 50 grams or more |
| Methamphetamine (mixture) | 50 grams or more | 500 grams or more |
| PCP (pure) | 10 grams or more | 100 grams or more |
| PCP (mixture) | 100 grams or more | 1 kilogram or more |
| LSD (mixture) | 1 gram or more | 10 grams or more |
| Marijuana | 100 kilograms or more, or 100 or more plants | 1,000 kilograms or more, or 1,000 or more plants |
Source: 21 U.S.C. § 841(b)(1)(A)–(B), current text.
Other rules in the same subsections:
- Death or serious bodily injury. If death or serious bodily injury results from use of the drug, the minimum is 20 years under either subsection.
- Maximums. The (b)(1)(B) range runs up to 40 years; the (b)(1)(A) range runs up to life.
- Supervised release. A sentence under (b)(1)(A) must include at least 5 years of supervised release, and under (b)(1)(B) at least 4 years, with longer minimum terms after a prior conviction.
Higher minimums after a prior conviction
Certain prior convictions raise the drug minimums (21 U.S.C. § 841(b)(1)(A)–(B)):
| Subsection | One prior "serious drug felony" or "serious violent felony" | Two or more |
|---|---|---|
| § 841(b)(1)(A) | 15 years | 25 years |
| § 841(b)(1)(B) | 10 years | No separate rule (10 years) |
The First Step Act of 2018 changed these rules (Pub. L. 115–391, § 401). Before it, any prior "felony drug offense" counted, and the (b)(1)(A) penalties were 20 years for one prior and mandatory life for two. Now only a "serious drug felony" or "serious violent felony" counts.
A "serious drug felony" is a drug offense described in 18 U.S.C. § 924(e)(2) for which the person served more than 12 months in prison and was released within 15 years before the new offense began (21 U.S.C. § 802(58)).
Two more rules matter:
- Notice is required. The higher penalty applies only if, before trial or a guilty plea, the prosecutor files a written notice (called an "information") listing the prior convictions (21 U.S.C. § 851(a)(1)).
- Timing. The First Step Act changes apply to offenses committed before December 21, 2018, only if a sentence had not yet been imposed on that date (First Step Act § 401(c)).
Gun charges under § 924(c)
Using or carrying a firearm during and in relation to a crime of violence or drug trafficking crime, or possessing one in furtherance of such a crime, carries its own minimums (18 U.S.C. § 924(c)):
| Conduct | Minimum |
|---|---|
| Use, carry or possess | 5 years |
| Brandished | 7 years |
| Discharged | 10 years |
| Short-barreled rifle or shotgun, or semiautomatic assault weapon | 10 years |
| Machinegun, destructive device, or firearm with a silencer or muffler | 30 years |
| Violation after a prior § 924(c) conviction has become final | 25 years |
The § 924(c) term must run consecutively, which means it is served after any other sentence, including the sentence for the underlying crime (§ 924(c)(1)(D)). Our § 924(c) guide covers the First Step Act's change to "stacking" and Dean v. United States.
The Armed Career Criminal Act
A person convicted of being a felon in possession of a firearm under 18 U.S.C. § 922(g), who has three prior convictions for a "violent felony" or "serious drug offense" committed on occasions different from one another, faces at least 15 years (18 U.S.C. § 924(e)(1)). A unanimous jury must find, beyond a reasonable doubt, that the prior offenses were committed on separate occasions (Erlinger v. United States, 602 U.S. 821 (2024)). Our Armed Career Criminal Act guide explains the predicates and how they are counted.
Child-exploitation offenses
Several federal child-exploitation crimes carry minimums:
- Production of child sexual abuse material: at least 15 years, rising to 25 years with one qualifying prior conviction and 35 years with two or more (18 U.S.C. § 2251(e)).
- Transporting, receiving or distributing such material: at least 5 years, or 15 years with a qualifying prior conviction (18 U.S.C. § 2252(b)(1); § 2252A(b)(1)).
- Possession: no mandatory minimum for a first offense, but a minimum applies with a qualifying prior conviction (§ 2252(b)(2); § 2252A(b)(2)).
How do mandatory minimums work with the guidelines?
The judge still calculates the guideline range first. If the mandatory minimum is higher than the maximum of the range, the minimum becomes the guideline sentence (USSG §5G1.1(b), Guidelines Manual, November 1, 2025). If the range is higher than the minimum, the judge works from the range, and the sentence still cannot fall below the minimum (§5G1.1(c)(2)).
The § 3553(a) factors let a judge vary below the guideline range. But they do not let a judge go below a statutory minimum. Only the exceptions Congress wrote, described next, do that.
What are the lawful ways below a mandatory minimum?
There are three, and each has strict conditions.
1. The safety valve (drug cases)
In certain drug cases, a defendant who meets five requirements is sentenced under the guidelines "without regard to any statutory minimum sentence" (18 U.S.C. § 3553(f)). The requirements include a limited criminal history, no weapon or violence, no leadership role, and full truthful disclosure to the government. See our safety valve guide.
2. A government motion for substantial assistance, § 3553(e)
"Upon motion of the Government," the court may go below a statutory minimum "to reflect a defendant's substantial assistance in the investigation or prosecution of another person" (18 U.S.C. § 3553(e)). The sentence is then imposed in line with the guidelines and policy statements.
Only the government can file this motion. The guidelines have a matching provision, §5K1.1, which allows a sentence below the guideline range on the government's motion; its commentary points to § 3553(e) as the authority for going below a statutory minimum (USSG §5K1.1 and comment. (n.1)). Since November 1, 2025, the Manual no longer calls §5K1.1 a "departure," but the substantial-assistance provision remains.
3. Rule 35(b), after sentencing
If the help comes after sentencing, the government may move to reduce the sentence under Fed. R. Crim. P. 35(b). The motion is generally due within one year of sentencing, with exceptions for information that became known or useful later. When acting under Rule 35(b), the court "may reduce the sentence to a level below the minimum sentence established by statute" (Rule 35(b)(4)).
Whether to cooperate is a serious decision with real risks. It should be made only with a lawyer's advice.
Common questions
What are mandatory minimums?
They are the lowest prison sentences that federal statutes allow for certain crimes. For example, trafficking 280 grams or more of a mixture containing crack cocaine carries at least 10 years (21 U.S.C. § 841(b)(1)(A)), and using or carrying a gun during a drug trafficking crime carries at least 5 more years (18 U.S.C. § 924(c)).
How do mandatory minimum sentences work?
The judge calculates the guideline range, and if the minimum is higher than the range, the minimum becomes the guideline sentence (USSG §5G1.1(b)). The judge cannot sentence below the minimum unless the safety valve applies (18 U.S.C. § 3553(f)) or the government files a substantial-assistance motion (18 U.S.C. § 3553(e)).
Can a mandatory minimum sentence be reduced?
Only in narrow ways the law allows. Before sentencing, the safety valve or a government motion under 18 U.S.C. § 3553(e) can take the sentence below the minimum. After sentencing, the government can move under Fed. R. Crim. P. 35(b) for substantial assistance, and the court may then go below the minimum (Rule 35(b)(4)). See how a federal sentence can be reduced for other routes.
What is the mandatory minimum for a 924(c) charge?
At least 5 years, or 7 if the gun was brandished and 10 if it was discharged, with higher minimums for certain weapons and 25 years for a violation after a prior § 924(c) conviction has become final (18 U.S.C. § 924(c)(1)). The term runs consecutively to any other sentence (§ 924(c)(1)(D)). See our § 924(c) guide.
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