Federal Exhibit Numbering Conventions: A Circuit-by-Circuit Cheat Sheet

There is no national rule for how federal exhibits get numbered. The Federal Rules of Civil Procedure don't prescribe a format, and the result is that each district court — and often each judge inside that district — picks its own convention. The Plaintiff's Ex. 1 you stamped for a Massachusetts case isn't the Plaintiff's Ex. P-1 your Texas co-counsel needs for a parallel filing. Mismatched conventions become courtroom embarrassments.

This is a cheat sheet to the six numbering systems federal districts actually use, with the courts that use each. State court rules generally borrow from these patterns but vary further — always check the specific state's civil procedure rules before assuming.

System 1 — Numbers for plaintiff, letters for defendant

The classic convention. Plaintiff's exhibits go 1, 2, 3…; defendant's exhibits go A, B, C…. When the alphabet is exhausted, defendants typically continue with AA, BB, CC, then AAA, BBB, CCC. If a defendant has more than ~78 exhibits, most courts allow a switch to numeric mode (so Defendant Ex. 80 makes more sense than Defendant Ex. CCC).

• Districts using this system: E.D.N.Y., D.N.H., E.D. Mich., D.P.R., D.N.D., D. Nev.
• Multi-defendant variation: the District of New Hampshire requires a defendant identifier prefix when there are multiple defendants — e.g., "Smith-A, Smith-B" vs. "Jones-A, Jones-B." See D.N.H.'s Procedure for Marking Exhibits.

System 2 — Party prefix + number (P-1 / D-1)

Each party uses a single prefix and a sequential number. Plaintiff exhibits are P-1, P-2…; defendant exhibits are D-1, D-2…. Joint exhibits, when present, use J-1, J-2 or JX-1, JX-2.

• Districts using this system: W.D. Tex., D. Colo. (judge-dependent), S.D. Fla.
• Why it's common: the prefix is unmistakable, so a stray exhibit floating around chambers can be re-attributed without context.

System 3 — Three-letter prefix + number (PTX-1 / DTX-1)

The District of Delaware's convention, common in patent and complex commercial cases. Trial exhibits get a three-letter prefix: PTX (Plaintiff Trial Exhibit), DTX (Defendant Trial Exhibit), JTX (Joint Trial Exhibit), then a sequential number — PTX-1, PTX-2, DTX-1, DTX-2, JTX-1.

• Districts using this system: D. Del.
• Why it's used: in IP and complex commercial cases with thousands of exhibits, the longer prefix makes grep/search across pleadings unambiguous.

System 4 — Number ranges per party

Plaintiff gets a numeric range (1–100), defendant gets a different range (101–200), joint exhibits get a third (201+). The exact band widths depend on case size; some judges set them in the pretrial order.

• Districts using this system: D. Or., W.D. Wis., E.D. Wis. (1–999 plaintiff, 1000–1999 defendant — large ranges to accommodate big productions).
• Watch out: running over your range is a real risk. If plaintiff's production grows past Ex. 100 and the range was 1–100, you'll be re-numbering mid-trial.

System 5 — Single continuous sequence (all parties)

One sequence across plaintiff, defendant, and joint exhibits — Ex. 1 might be plaintiff's, Ex. 2 might be defendant's, Ex. 3 might be joint. The exhibit list itself indicates which party offered each. Less common, but the simplest scheme to administer in short trials.

• Districts using this system: D. Mass., N.D. Cal. (judge-dependent), E.D. Tenn.
• Trade-off: easy to administer, but a stray exhibit shows nothing about who offered it without referring back to the list.

System 6 — Party-prefixed sub-numbering for composite exhibits

Most districts allow composite exhibits — a single exhibit containing multiple sub-parts that share a common subject (e.g., ten emails in a single chain). The composite gets one number and alphabetic suffixes: Ex. 1/A, Ex. 1/B, Ex. 1/C. The Middle District of Florida's Local Rule 3.07 is the canonical example.

What about deposition exhibits?

Deposition exhibits typically use a separate sequence per deponent — "Smith Ex. 1, Smith Ex. 2…" — regardless of the trial numbering scheme. Increasingly, federal courts in complex cases require a continuous deposition exhibit sequence across all deponents to avoid the Smith-Ex.-3 vs. Jones-Ex.-3 confusion at trial.

Quick lookup

• Numbers / Letters: E.D.N.Y., D.N.H., E.D. Mich., D.P.R., D.N.D., D. Nev.
• Party Prefix + Number (P-1 / D-1): W.D. Tex., D. Colo., S.D. Fla.
• Trial Prefix + Number (PTX-1 / DTX-1): D. Del.
• Number Ranges: D. Or., W.D. Wis., E.D. Wis.
• Single Sequence: D. Mass., N.D. Cal., E.D. Tenn.

When in doubt, the AO-187 form is your single source of truth — pick the system the form requires and stamp the exhibits to match. See the AO-187 guide.