Grand jury vs. trial jury: what's the difference?

If your summons says "grand jury," you're being asked to do something quite different from the courtroom trials most people picture. Here's how the U.S. Courts describe the two federal jury types. Many states use both too, with their own variations.

Petit (trial) jury

A petit jury is a trial jury. It decides both criminal and civil cases.

• Criminal cases: the jury decides whether the government has proved beyond a reasonable doubt that the defendant committed the crime charged.
• Civil cases: the jury decides whether the plaintiff has shown, by a preponderance of the evidence (more likely than not), that the defendant injured the plaintiff in a way that calls for compensation. The U.S. Courts note this is a much lower standard than in a criminal trial, because nobody's freedom is at stake.

Federal petit juries have 6 to 12 members. Trials are generally public, but deliberations are private. A petit juror hears one case at most and is then discharged.

Grand jury

A grand jury deals only with the early stage of criminal cases. It hears evidence presented by a prosecutor and decides whether there's "probable cause" to believe someone committed a crime and should be put on trial. If so, it issues an indictment. The federal trial jurors' handbook explains that an indictment is a written accusation by a grand jury charging the defendant with an offense.

• Size: 16 to 23 grand jurors.
• Secrecy: proceedings are private.
• Term: federal grand jurors generally serve up to 18 months, extendable to 24 months by a judge, and hear many cases over that time.
• Schedule: grand juries don't sit every day. A grand jury in a smaller district may meet one day every other week. In a busy district it may meet a couple of days each week.

Pay

Federal grand and petit jurors both earn $50 a day. The U.S. Courts say petit jurors may get up to $60 a day after 10 days if the presiding judge orders it, and grand jurors may get up to $60 a day after 45 days of service. Use the pay calculator to estimate.

Planning for grand jury service

Because grand jury service stretches over months, the scheduling questions are different. Ask the jury office for the meeting calendar as soon as possible, give it to your employer, and raise conflicts early. If the commitment would be a genuine hardship, say so when you respond. See how to postpone jury duty and jury duty and your job.

State grand juries

Not every state uses grand juries the same way. Some use them for most serious charges, others rarely. If you're summoned to a state grand jury, your state's jury page and the court's orientation will explain the term and schedule.

What each jury actually decides

The clearest way to see the difference is to compare the question each jury answers:

• A trial (petit) jury decides guilt or liability. In a criminal case it asks whether the government has proved beyond a reasonable doubt that the defendant committed the crime charged. In a civil case it asks whether the plaintiff has proved the claim by a preponderance of the evidence, meaning "more likely than not."
• A grand jury decides whether there is probable cause to believe a person committed a crime and should be put on trial. If it finds enough evidence, it issues an indictment. It doesn't decide guilt.

Size, secrecy and schedule compared

	Trial (petit) jury	Federal grand jury
Number of jurors	6 to 12	16 to 23
Proceedings	Generally public; deliberations private	Private
Cases heard	One, then discharged	Many over the term
Term	Length of one trial	Generally up to 18 months; up to 24 with an extension
Meeting pattern	Daily during the trial	Periodic, e.g. one day every other week in a smaller district, or a couple of days a week in a busy one

Who presents evidence

At trial, both sides present evidence. Witnesses are cross-examined, and the judge rules on objections and instructs the jury on the law. A grand jury session is different. A prosecutor presents the evidence, there is no judge in the room during the presentation, and the person under investigation generally doesn't present a case. Grand jurors can ask questions and request more evidence. Because the process is secret, grand jurors are bound not to disclose what happens in the room.

How the pay works out

Federal grand jurors are paid $50 a day, the same daily rate as trial jurors. Grand jurors become eligible for up to $60 a day after serving 45 days, while trial jurors can reach $60 after 10 days if the judge orders it. Transportation reimbursement applies to both, and federal employees receive their regular salary instead of the fee. Because grand juries meet only on scheduled days, your total pay depends on how often your panel convenes, not on the calendar length of the term.

Talking to your employer about a long term

A grand jury summons can sound alarming ("up to 18 months?"), but remember that it's part-time. When you tell your employer:

1. Share the meeting schedule as soon as the court gives it to you, for example "every other Tuesday."
2. Point out that federal law protects permanent employees from being fired, threatened or coerced because of federal jury service (28 U.S.C. § 1875). Our jury duty and your job guide has the details.
3. Ask HR whether your company's jury pay policy has a cap on days. Some policies are written with short trial service in mind.
4. If the schedule creates a genuine hardship, ask the jury office promptly whether you can be deferred or reassigned.

Frequently asked questions

Can I be on a grand jury and a trial jury at the same time? In practice, no. Courts don't put someone on a trial panel while they're serving a grand jury term.

Do grand juries exist in state courts? Many states use them, but how often and for what varies. Some states charge most felonies by a prosecutor's filing (an "information") followed by a preliminary hearing before a judge.