Specifications

Denomination: multiple
Series: Mint error types

A double strike shows two overlapping images because the coin failed to eject and was struck again — usually with the second strike landing off-center. Dramatic, widely offset second strikes on early copper are the prize pieces: a double-struck 1794 cent in MS66 was the highlight of Heritage’s ANA sale.

Wikimedia Commons (Economicrealist), CC BY-SA 3.0

What it is

A double strike is a striking-stage error — what Heritage executive vice president Todd Imhof describes as “a coin that has two (or more) images because the planchet was impressed (at least) twice” (Numismatic News — Double-Struck Cent Highlights Heritage ANA Sale; accessed 2026-09-17).
The diagnostics are two overlapping design impressions, often with the second visibly rotated or shifted off-center (Wikipedia — Mint-made errors; accessed 2026-09-17).

How it happens

A struck coin fails to eject from the coining chamber and is struck again by the dies (Wikipedia — Mint-made errors; Numismatic News — Double-Struck Cent Highlights Heritage ANA Sale; accessed 2026-09-17).
The second strike usually lands off-center, overlaying a shifted or rotated image on top of the first (Wikipedia — Mint-made errors; accessed 2026-09-17).
On occasion the coin flips over between strikes, so the second image is that of the opposite side of the coin — a flip-over double strike (Wikipedia — Mint-made errors; accessed 2026-09-17).

How to identify

Look for two overlapping images, usually with the second strike landing off-center — that is the classic double-strike look (Wikipedia — Mint-made errors; Numismatic News — Double-Struck Cent Highlights Heritage ANA Sale; accessed 2026-09-17).
Do not confuse it with a doubled die: doubling on a doubled die is made when the die is hubbed twice, not when the coin is struck twice (Wikipedia — Mint-made errors; accessed 2026-09-17).
Flip-over double strikes show the opposite side’s design on one face — a dramatic and desirable variant (Wikipedia — Mint-made errors; accessed 2026-09-17).
Both strikes showing the date is a major plus for value (Numismatic News — Double-Struck Cent Highlights Heritage ANA Sale; accessed 2026-09-17).

Real error vs. post-mint damage

A genuine double strike shows two raised, properly oriented design impressions from the dies, with normal mint surfaces (Wikipedia — Mint-made errors; accessed 2026-09-17).
Post-mint compression — for example a coin crushed against another coin or flattened by a train — can press a mirrored, incuse image into a coin’s surface; that is damage, not a double strike (Wikipedia — Mint-made errors; accessed 2026-09-17).

Notable examples

1794 S-28 Head of 1794 cent, double-struck, MS66 Brown NGC — one of four S-28 cents tied for finest known; its double strike, with both strikes off-center showing the date, made it the highlight of Heritage’s ANA U.S. Coins Signature Auction. The coin had previously been chosen to introduce the error chapter of Walter Breen’s Encyclopedia of Early United States Cents, 1793–1814 (Numismatic News — Double-Struck Cent Highlights Heritage ANA Sale; accessed 2026-09-17).
1787 Fugio cent, double-struck with second strike 35% off-center, Fine 15 NGC (Heritage; accessed 2026-09-17).
(1971–1978) Eisenhower dollar, double-struck with second strike 50% off-center, MS62 PCGS (Heritage; accessed 2026-09-17).
1976-D Bicentennial half dollar, double-struck with second strike 85% off-center, MS64 PCGS (Heritage; accessed 2026-09-17).
1973-S Kennedy half dollar, triple-struck with second and third strikes 35% off-center, PR67 Ultra Cameo NGC (Heritage; accessed 2026-09-17).

What drives value

Premiums track drama and preservation: widely offset second strikes, both strikes visible with the date showing, early copper, and high grade (Numismatic News — Double-Struck Cent Highlights Heritage ANA Sale; accessed 2026-09-17).
Triple and higher multiple strikes — three or more impressions — are more dramatic still and command stronger interest than simple double strikes (Numismatic News — Double-Struck Cent Highlights Heritage ANA Sale; Wikipedia — Mint-made errors; accessed 2026-09-17).