Federal Mandatory Minimum Sentences Explained

By Elizabeth Franklin-Best, Esq., and Christopher Zoukis, JD, MBA

Most of federal sentencing is a system of discretion — advisory guidelines, statutory factors, and a judge weighing the whole case. Mandatory minimum sentences are the exception. When a statute sets a mandatory minimum, it imposes a floor: the court generally cannot sentence below it, no matter what the Guidelines suggest or what the circumstances of the defendant might otherwise warrant.

At Elizabeth Franklin-Best, P.C., we identify mandatory minimum exposure early and pursue every available route around it. Principal attorney Elizabeth Franklin-Best — named a “Best Lawyer” in Appellate Practice by Best Lawyers in America 2026 and ranked by Chambers USA 2026 for Litigation: White-Collar Crime & Government Investigations — leads that work, and Managing Director Christopher Zoukis brings the firm deep knowledge of how mandatory terms play out inside the federal prison system. Mandatory minimums appear most prominently in 21 U.S.C. § 841 and 18 U.S.C. § 924(c).

This guide explains how federal mandatory minimums work — what they are, how they apply in drug and firearm cases, how the firearm penalties stack and run consecutively, and the two recognized routes below a mandatory minimum. If you are facing a charge that carries a mandatory minimum, understanding that floor is essential to understanding your real exposure.

Quick Answer

Question	Answer
What is a mandatory minimum sentence?	A statutory floor — a term of imprisonment a court generally cannot go below for a defendant convicted of the offense, regardless of the Guidelines or the 3553(a) factors.
Where do drug mandatory minimums come from?	From 21 U.S.C. § 841, where the mandatory minimum is driven primarily by the type and quantity of the controlled substance, and can be enhanced by certain factors.
What is a 924(c) mandatory minimum?	An additional, consecutive mandatory term for using, carrying, or possessing a firearm in connection with a drug trafficking or violent crime, starting at not less than five years.
Can a court ever go below a mandatory minimum?	Yes, through two routes: a government substantial-assistance motion under 18 U.S.C. § 3553(e), or the statutory safety valve under § 3553(f).
Does the safety valve require a government motion?	No. Unlike substantial assistance, safety-valve eligibility is determined by the court, not dependent on a government motion.
Who decides the facts that trigger a minimum?	The jury. Under Alleyne v. United States, any fact that raises a mandatory minimum must be charged and proved beyond a reasonable doubt.
How do I learn my actual exposure?	In a paid, one-hour initial consultation we map the statutory floors in your case and every realistic route below them.

Key Takeaways

• A mandatory minimum is a statutory floor — the court generally cannot sentence below it, unlike the advisory Guidelines.
• Drug mandatory minimums under 21 U.S.C. § 841 are driven primarily by the type and quantity of the controlled substance.
• Section 924(c) imposes additional mandatory minimums for firearms used, carried, or possessed in connection with drug or violent crimes.
• A 924(c) sentence runs consecutively — added on top of the sentence for the underlying offense.
• Under Alleyne v. United States, any fact that raises a mandatory minimum must be charged and found by the jury beyond a reasonable doubt.
• In fraud cases, aggravated identity theft under 18 U.S.C. § 1028A adds a flat two-year consecutive term — a reach the Supreme Court narrowed in Dubin.
• The First Step Act ended 924(c) “stacking” within a single prosecution and broadened safety-valve eligibility.
• There are two routes below a mandatory minimum: a government substantial-assistance motion and the safety valve.
• The safety valve does not require a government motion; eligibility is decided by the court.
• Mandatory minimum analysis belongs at the very start of a case, because it reshapes exposure and strategy.

What Is a Mandatory Minimum Sentence?

A mandatory minimum sentence is a statutory floor. When Congress writes a mandatory minimum into a criminal statute, it directs that a defendant convicted of that offense must receive at least the specified term of imprisonment. The court cannot go below it.

This makes a mandatory minimum fundamentally different from the advisory Sentencing Guidelines. The Guidelines produce a recommended range that a judge can sentence above or below based on the statutory factors. A mandatory minimum admits no such discretion. Even if the Guidelines range, the 3553(a) factors, and every consideration of mitigation pointed to a lower sentence, the court is bound by the statutory floor.

Because of this, the first question in any case that might carry a mandatory minimum is whether one applies, and at what level. The answer reshapes everything — the realistic sentencing exposure, the value of any Guidelines argument, and the strategy of the entire case. A mandatory minimum is not just one factor among many; it is a structural fact that the rest of the defense must be built around.

Drug Mandatory Minimums

The most common federal mandatory minimums appear in drug cases, under 21 U.S.C. § 841. For drug trafficking offenses, the mandatory minimum is driven primarily by the type and quantity of the controlled substance involved.

Section 841(b) sets tiered penalties keyed to specific quantity thresholds, and two tiers do most of the work. Under § 841(b)(1)(B), intermediate quantities trigger a five-year mandatory minimum. Under § 841(b)(1)(A), the largest quantities trigger a ten-year mandatory minimum. The thresholds differ by substance:

Substance	5-Year Minimum — § 841(b)(1)(B)	10-Year Minimum — § 841(b)(1)(A)
Heroin	100 grams or more	1 kilogram or more
Powder cocaine	500 grams or more	5 kilograms or more
Cocaine base (crack)	28 grams or more	280 grams or more
Methamphetamine (actual)	5 grams or more	50 grams or more
Methamphetamine (mixture)	50 grams or more	500 grams or more
Fentanyl	40 grams or more	400 grams or more

Aggravating facts raise these floors further. If death or serious bodily injury results from use of the drug, the § 841(b)(1)(A) minimum becomes twenty years. A prior conviction for a “serious drug felony or serious violent felony” raises the ten-year floor to fifteen years, and two such priors raise it to twenty-five — but only if the government formally invokes the prior through an information filed under 21 U.S.C. § 851. The First Step Act of 2018 softened this structure: it reduced the enhanced minimums (which previously ran from twenty years to mandatory life) and narrowed the categories of priors that qualify. Whether a client’s record actually contains a qualifying prior is a litigable question, and the government’s charging discretion over the § 851 notice is often a central topic in plea negotiations.

Because drug quantity is the key driver, the determination of quantity is one of the most important issues in a drug case. What quantity is attributable to a particular defendant — including under the relevant-conduct rules in a conspiracy — directly determines which mandatory minimum applies, or whether one applies at all. Quantity is litigable, and litigating it can mean the difference between a mandatory minimum and none.

Applied Insight: In drug cases, the mandatory minimum often turns on a quantity threshold — a specific number of grams or kilograms. A defendant whose attributable quantity sits just above a threshold faces a far harsher floor than one just below it. Litigating quantity, and the attribution of quantity in a multi-defendant conspiracy, is therefore not a technicality — it can decide whether a mandatory minimum exists at all.

Firearm Mandatory Minimums Under 924(c)

The other major source of federal mandatory minimums is 18 U.S.C. § 924(c). This statute applies to a person who uses or carries a firearm during and in relation to a crime of violence or a drug trafficking crime, or who possesses a firearm in furtherance of such a crime.

Section 924(c) carries its own mandatory minimum terms, and the term depends on what was done with the firearm. The base mandatory minimum is five years. If the firearm was brandished, the minimum rises to seven years; if it was discharged, to ten. Certain weapon types carry far harsher floors — a machinegun or a destructive device, for example, triggers a thirty-year mandatory minimum. And for a § 924(c) offense committed after a prior § 924(c) conviction has become final, the minimum jumps to twenty-five years.

The defining feature of § 924(c) is that its sentence is additional. The 924(c) mandatory minimum is imposed on top of the punishment for the underlying drug or violent crime — and, as discussed next, it generally must run consecutively. A 924(c) count attached to another charge is, in effect, a separate block of mandatory time stacked on top of everything else.

Stacking and Consecutive Sentences

Two features of § 924(c) make it especially severe: consecutive sentencing and stacking.

Consecutive sentencing means the 924(c) term cannot run at the same time as the sentence for the underlying offense. By statute, the 924(c) sentence runs after — on top of — the sentence for the drug or violent crime. A five-year 924(c) count is five years added to whatever the underlying offense carries, not five years absorbed into it.

Stacking refers to the escalated twenty-five-year mandatory minimum for a repeat 924(c) conviction. Historically, prosecutors could “stack” multiple 924(c) counts within a single case, so that a defendant facing several counts in one prosecution faced the escalated penalties even with no prior record — five years on the first count, then twenty-five on each additional count, all consecutive. The First Step Act of 2018 changed this: the twenty-five-year penalty now applies only where the prior 924(c) conviction was already final when the new offense occurred, which ended stacking within a single prosecution.

The Supreme Court extended that reform in Hewitt v. United States, 606 U.S. 419 (2025), holding that a defendant originally sentenced before the First Step Act whose sentence has since been vacated is entitled to the Act’s more lenient 924(c) penalties at resentencing. For anyone still serving a stacked pre-2018 sentence, or facing resentencing on one, whether the escalated penalty genuinely applies under current law should always be carefully analyzed.

The Armed Career Criminal Act: A 15-Year Minimum for Felon-in-Possession

A third major firearm mandatory minimum lives in the same statute but works very differently from § 924(c). The Armed Career Criminal Act, 18 U.S.C. § 924(e), imposes a fifteen-year mandatory minimum on a defendant convicted of being a felon in possession of a firearm under § 922(g) who also has three prior convictions for a “violent felony” or “serious drug offense” committed on occasions different from one another. Where an ordinary felon-in-possession conviction carries no mandatory minimum at all, the ACCA designation converts it into a fifteen-year floor — one of the largest single swings in federal sentencing law.

Because the stakes are so high, the threshold questions are heavily litigated. Whether a prior conviction actually qualifies turns on the categorical approach, which compares the elements of the prior offense to the federal definition rather than asking what the defendant in fact did. The Supreme Court has steadily narrowed what counts: in Borden v. United States, 593 U.S. 420 (2021), the Court held that an offense requiring only a reckless mental state cannot be a “violent felony,” because the elements clause demands force directed against another person. And in Erlinger v. United States, 602 U.S. 821 (2024), the Court held that the “occasions different from one another” question — whether the three priors were truly separate — is itself a fact that a jury must find beyond a reasonable doubt, not a matter for the judge. Each holding is a place where an ACCA enhancement can be defeated, and each can mean the difference between a guideline sentence and a fifteen-year floor.

Facts That Raise the Floor Must Go to the Jury

A mandatory minimum does not apply just because a prosecutor asserts it. In Alleyne v. United States, 570 U.S. 99 (2013), the Supreme Court held that any fact that increases a mandatory minimum sentence is an element of the offense — it must be charged, submitted to the jury, and found beyond a reasonable doubt. A judge cannot impose a higher statutory floor based on facts found only by a preponderance at sentencing.

This rule has teeth in exactly the cases this guide covers. The drug quantity that moves a case from no minimum to five years, or from five to ten, is an Alleyne fact. So is brandishing or discharging a firearm under § 924(c), each of which raises the minimum. In a trial, the government must prove those threshold facts to the jury; in a plea, the defendant’s own admissions in the agreement and colloquy can establish them — which is one more reason the precise wording of a plea agreement deserves close scrutiny before anyone signs it.

The Two-Year Minimum in Fraud Cases: Aggravated Identity Theft

Mandatory minimums are not confined to drug and firearm cases. In white-collar prosecutions, the one that matters most is 18 U.S.C. § 1028A, aggravated identity theft. It imposes a flat two-year term on anyone who, during and in relation to an enumerated felony — including mail, wire, and bank fraud — knowingly uses another person’s means of identification without lawful authority.

The statute is engineered to guarantee additional prison time. Probation is prohibited, the two years cannot run concurrently with the sentence for the underlying fraud, and the statute forbids the court from trimming the underlying sentence to compensate for the add-on. That structure gives prosecutors enormous plea leverage, which is why the count is so often charged in fraud indictments.

The Supreme Court cut back on that leverage in Dubin v. United States, 599 U.S. 110 (2023), holding that § 1028A applies only when the misuse of another person’s identity is at the crux of what makes the conduct criminal — not whenever a name or identifying number appears somewhere in a fraudulent transaction, as in routine overbilling. Where the government stretches the statute past Dubin, the count is vulnerable, and challenging it can remove two mandatory years from the case.

The Two Routes Below a Mandatory Minimum

A mandatory minimum is a floor — but it is not always an absolute one. Federal law recognizes two routes that allow a court to sentence below a mandatory minimum.

Substantial Assistance

The first route is a government motion for substantial assistance. Under 18 U.S.C. § 3553(e), upon a motion of the government, the court has the authority to impose a sentence below a statutory mandatory minimum to reflect the defendant’s substantial assistance in the investigation or prosecution of another person. This route depends entirely on the government — without its motion, the court generally cannot go below the minimum on this basis.

Two technical distinctions matter here. First, a motion under Guidelines § 5K1.1 alone authorizes a sentence below the advisory range but not below the statutory minimum; piercing the floor requires the government to invoke § 3553(e) as well, so the scope of the government’s motion should be confirmed, not assumed. Second, cooperation that comes to fruition after sentencing is not wasted: on a government motion under Federal Rule of Criminal Procedure 35(b), the court may later reduce a sentence — including below the mandatory minimum — for substantial assistance provided after the original sentencing.

The Safety Valve

The second route is the statutory safety valve, found in 18 U.S.C. § 3553(f). The safety valve allows certain non-violent drug defendants who meet a defined set of criteria — relating to criminal history, the absence of violence and weapons, the defendant’s role, and a truthful disclosure to the government — to be sentenced without regard to the mandatory minimum. Unlike substantial assistance, the safety valve does not require a government motion; eligibility is determined by the court. The First Step Act of 2018 broadened safety-valve eligibility.

Identifying whether either route is available is one of the first and most important tasks in a mandatory-minimum case. For an eligible defendant, the safety valve in particular can transform the realistic exposure of a case.

How Mandatory Minimums Shape a Case

A mandatory minimum changes the strategy of an entire case, well before sentencing. Because the floor is fixed, the most important early questions become whether a mandatory minimum applies at all, and whether a route around it exists.

This affects charging and plea negotiations directly. A charge that carries a mandatory minimum, and a charge that does not, can lead to very different outcomes for similar conduct — which is why the specific counts of conviction matter so much. It also shapes the value of a Guidelines argument: where a mandatory minimum exceeds the bottom of the advisory range, a successful Guidelines reduction may not lower the sentence at all unless a route below the minimum is also available.

For all of these reasons, mandatory minimum analysis cannot wait until sentencing. It belongs at the very start of the case — informing the assessment of exposure, the approach to negotiation, and the litigation of facts, such as drug quantity, that determine whether the floor applies.

Applied Insight: The hardest thing about a mandatory minimum is that it makes ordinary mitigation powerless against the floor. A defendant with a compelling personal history, a minor role, and full acceptance of responsibility can still be bound by the statutory minimum. That is exactly why the early work — contesting whether the minimum applies, and pursuing the safety valve or substantial assistance — is so decisive. Those are the levers that actually move the floor.

How Our Firm Addresses Mandatory Minimums

At Elizabeth Franklin-Best, P.C., we treat mandatory minimum analysis as a first-order priority in any case where one may apply. Our principal attorney, Elizabeth Franklin-Best, has appeared in more than 330 federal proceedings, including over 100 appeals, and is admitted before the U.S. Supreme Court and all twelve federal circuit courts of appeals. That appellate vantage shapes how we litigate a floor from day one: if a threshold fact, a § 851 notice, or a stacking issue needs to be preserved for review, it gets preserved. She is also the 2026 Best Lawyers in America “Best Lawyer” in Appellate Practice, holds a Chambers USA 2026 ranking in Litigation: White-Collar Crime & Government Investigations, and is the author of Reversing Your Criminal Conviction.

The discipline that carries the heaviest sentencing stakes informs the lighter ones. Elizabeth Franklin-Best served as counsel in Aiken v. Byars, 410 S.C. 534 (2014), the landmark decision requiring individualized resentencing for juveniles serving life under Miller v. Alabama, and she has litigated capital sentencing and mitigation in matters such as Morva v. Zook, 821 F.3d 517 (4th Cir. 2016). Building a record where a single statutory floor decides decades of a person’s life is the same craft, applied here to drug quantity, § 924(c) terms, and the priors a § 851 notice tries to invoke. The firm’s sentencing and post-conviction practice runs nationwide through pro hac vice admission, with a concentration in First Step Act § 404 resentencings and Amendment 821 reductions — the very provisions that decide whether an old mandatory-minimum sentence still stands.

Our work includes determining at the outset whether a mandatory minimum applies and at what level, litigating drug quantity and the other Alleyne facts that drive the minimum, testing 924(c) and § 1028A counts against current Supreme Court law, evaluating safety-valve eligibility, and assessing whether substantial assistance is a realistic route. We build the rest of the defense around an accurate understanding of the floor. Wherever a federal case is pending, pro hac vice admission lets us appear in that district.

For related reading, see our federal sentencing overview, our guide to the safety valve, and our federal drug crimes hub.

Talk With a Federal Sentencing Lawyer

A mandatory minimum sets a hard floor under a sentence — but whether that floor applies, and whether a route around it exists, are questions that demand careful, early analysis. Those questions can change the entire trajectory of a case.

We begin every engagement with a paid, one-hour initial consultation devoted to your specific charges: which statutory floors are in play, which facts the government must actually prove to trigger them, and which of the relief valves — safety valve, substantial assistance, or a charging challenge — realistically fits your case. If a mandatory minimum may be hanging over you, that hour is the place to start.