How Many People Are Needed for a Class Action Lawsuit?

Quick Answer: There is no fixed number. Federal Rule 23 only requires that the class be “so numerous that joinder of all members is impracticable.” In practice, courts often treat about 40 or more people as enough, and groups under about 20 usually are not. Federal court jurisdiction under the Class Action Fairness Act separately requires at least 100 class members.

Key Takeaways

Rule 23(a) sets no minimum class size, only that joining everyone must be impracticable
A common rule of thumb is that 40 or more members is plenty and that 15 or fewer is too few
Classes between those numbers are judged case by case
You do not need to find the other members yourself
Federal courts hear most big class actions under CAFA only if there are at least 100 members and over $5 million at stake

How Many Plaintiffs Do You Need for a Class Action?

Quick Answer: Only one person has to file as the named plaintiff. They represent a class of other people, who do not need to sign up in advance. The class must be large enough that one case is more practical than many.

That surprises many people. One person, through an attorney, can file on behalf of thousands or millions. The other members are identified later through company records, notice campaigns and claim forms. See how to start a class action lawsuit for the steps.

What Does the Law Say About Class Size?

Quick Answer: Rule 23(a)(1) calls this requirement numerosity. It asks whether the class is so numerous that bringing all the members into one case is impracticable. The rule gives no number.

You can read the exact wording in Federal Rule of Civil Procedure 23. Numerosity is only one of four requirements. The class must also share common questions, have typical claims and be fairly represented. Judges look at the practical facts, such as how spread out the members are, whether each person’s claim is small and whether individuals could realistically sue alone.

Is 40 the Magic Number?

Quick Answer: It is a rule of thumb, not a law. Courts tend to see more than 40 members as enough, but a smaller class can still qualify, and a larger one can still fail if joining everyone would be easy.

A National Law Review article about the Third Circuit decision in In re Modafinil Antitrust Litigation says the court applied close scrutiny to classes with more than 15 but fewer than 40 members and reversed certification of a 22 member class. It summarizes the practical lesson as “15 is too few, and 40 is plenty,” while noting the rule itself sets no number. Another judge in another court may weigh the facts differently, so treat these figures as general guidance.

How Many People Are Needed for Federal Court?

Quick Answer: For federal jurisdiction under the Class Action Fairness Act, a class generally needs at least 100 members and more than $5 million in controversy, with at least one class member and one defendant from different states. Smaller cases usually go to state court.

These thresholds are in 28 U.S.C. section 1332(d). They decide which court hears the case, not whether the class is large enough to be certified. A smaller class action can proceed in state court under that state’s own rules.

Real Examples of Class Sizes

Real classes range widely. The Knott’s Berry Farm and Great America case covers about 1.4 million California ticket buyers according to settlement trackers, as covered in our Knott’s settlement guide. The Conduent and other data breach cases involve tens of millions of people. At the other end, specialized cases such as a single employer wage case may involve only a few dozen workers.

Common Questions About Class Action Size

How many people are required for a class action suit?

No set number. The class must be too large for everyone to join one case practically, and about 40 or more is often considered enough.

Can a class action have only 10 people?

It is unlikely. With so few people, a court will usually say they could join one ordinary lawsuit instead.

Do I have to find other people to start a class action?

No. Your attorney defines the class and the company’s records help identify its members.

How many plaintiffs do you need for a class action?

One named plaintiff is enough to file, though some cases have several.

Does a bigger class mean a bigger payout?

Not for each person. A bigger class often splits the money into smaller shares. See how payouts are calculated.

Where can I learn what a class action is?

Start with our guide to what a class action lawsuit is.

Summary

There is no exact number of people needed for a class action. The law asks whether the group is too large to join in one case, courts often see 40 or more as enough, and federal court under CAFA generally needs at least 100 members. One named plaintiff can start the case.

Disclaimer: This article is general information, not legal advice. Courts apply these rules differently. Consult a qualified attorney about your situation.