The Ultimate Us Coin Sizing Guide: Diameter, Thickness, and Millimeter Specs
By Marcus Vance
Knowing how coins compare in scale allows you to construct improvised vernier scales or verify step-down measurements in a workshop. The dime holds a unique place in this hierarchy: despite representing ten cents, it remains smaller in both diameter and thickness than the one-cent piece.
| Denomination | Diameter (mm) | Thickness (mm) | Weight (g) | Edge Details |
|---|---|---|---|---|
| Dime (10¢) | 17.91 mm | 1.35 mm | 2.268 g | 118 reeds |
| Penny (1¢) | 19.05 mm | 1.52 mm | 2.500 g | Plain / Smooth |
| Nickel (5¢) | 21.21 mm | 1.95 mm | 5.000 g | Plain / Smooth |
| Quarter (25¢) | 24.26 mm | 1.75 mm | 5.670 g | 119 reeds |
| Half Dollar (50¢) | 30.61 mm | 2.15 mm | 11.340 g | 150 reeds |
| Native American / Innovation Dollar | 26.49 mm | 2.00 mm | 8.100 g | Edge-lettered |
When assessing a quarter vs dime size mm spread, the difference is substantial. A quarter measures 24.26 mm across, giving it a 6.35 mm wider footprint and an additional 0.40 mm in rim thickness. The penny diameter mm sits between them at 19.05 mm, which frequently surprises people who assume face value dictates physical circumference.
Marcus Vance is a cybersecurity auditor and technology writer dedicated to educating the public about online safety, data privacy regulations, enterprise security, and emerging cyber threats.
