US nickel
A US nickel is a five-cent coin made primarily of a copper-nickel alloy.
How big is it?
2.121 cm across
Also 0.835 in
Diameter · specified
Format: Cupro-nickel. US nickel: 21.21 mm (0.835 in) in diameter, 1.95 mm (0.077 in) thick, and 5 g in mass. Diameter measures across the face, not the edge thickness.
Check US nickel material and older-format differences. Compare UK and US coin dimensions.
A little perspective
US nickel vs UK 20p coin: diameter comparison
The maximum diameter of a UK 20p coin is about 1.01 times the diameter of a US nickel.
A UK 20p coin is the seven-sided twenty-pence denomination of the decimal pound sterling circulation coinage.
Both rulers start at the same zero and share one linear scale. Artwork keeps its original proportions.
Measurements, assumptions & sources +
US nickel
Diameter: 2.121 cm; specified.
Cupro-nickel US nickel: 21.21 mm diameter, 1.95 mm thickness and 5 g mass. These nominal specifications do not describe every historical composition.
US Mint — circulating coin specifications
The marked diameter is calibrated. Unmeasured illustration details are representative.
UK 20p coin
Specified maximum diameter: 2.14 cm; specified.
Cupro-nickel UK 20p: 21.4 mm maximum span, 1.7 mm thickness and 5 g mass. Its equilateral-curve heptagon has constant breadth; a different portrait or reverse does not by itself change these specifications.
Royal Mint — 20p specifications
The marked specified maximum diameter is calibrated. Unmeasured illustration details are representative.
Use the visual comparison to explore its scale, then check the measurements and sources.
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Why this measurement?
Why we use 2.121 cm
We compare the diameter of a US nickel. This value follows a stated specification; check its scope in the notes.
Cupro-nickel US nickel: 21.21 mm diameter, 1.95 mm thickness and 5 g mass. These nominal specifications do not describe every historical composition.
The marked horizontal span follows the measured feature, not the edges of the image. How calibrated comparisons work →
Recorded properties
Dimensions and measurements
| Property | Selected value | Recorded range | Basis |
|---|---|---|---|
| 21.21 mm (0.835 in) | Not recorded | specified - Cupro-nickel | |
| 5 g | Not recorded | specified - Cupro-nickel | |
| 1.95 mm (0.077 in) | Not recorded | specified - Cupro-nickel |
Around this scale
Explore nearby values.
Compare examples with lower, similar and higher values. Each card names the measurement being compared.
Nearest lower valueEveryday objectsUK 1p coin2.03 cmSpecified diameterA UK 1p coin is the one-penny denomination of the decimal pound sterling circulation coinage.
Around the same scaleEveryday objects20 × 30 mm stamp2 cmWidthA postage stamp is a small adhesive label placed on mail to show payment for postal services.
Nearest higher valueEveryday objectsUK 20p coin2.14 cmSpecified maximum diameterA UK 20p coin is the seven-sided twenty-pence denomination of the decimal pound sterling circulation coinage.Sources and method
Want to check the number?
The source records and measurement method remain available for inspection.
- US Mint — circulating coin specificationsNominal format specifications. Direct retrieval returned HTTP 403 during the October 2026 review; additional references identify the thickness values used.
- CoinNews — US circulating coin specificationsSecondary corroboration of nickel, dime and quarter thicknesses and format masses. Its older penny thickness differs; that value is not used.
More ways to see it
Curated comparisons
There’s always another scale
Follow your curiosity.
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