Inputs
Gross weight in grams + diameter in millimetersCompare measurements with sourced reference data
Gold Coin Weight and Diameter Checker
Select a supported coin size, enter measured gross weight and diameter, and compare both measurements with its issuer/reference specifications. The tool reports signed differences and absolute percentage differences; it does not classify the coin.
Source-based reference
Source-basedNo live quote needed for this referenceOutputs
Reference, signed difference and absolute percent differenceScope
Only coin sizes with sourced dimensionsSpecification and intent
A measurement comparison is a screening worksheet
The tool uses the shared canonical coin dataset for current bullion coins and the Royal Mint Museum's Sovereign-family table. It shows the selected reference beside your inputs so the comparison is transparent and reproducible.
Interactive tool
Compare your measurements
Use a suitable scale and caliper; enter positive values in grams and millimeters. A physical measurement match alone cannot establish a coin's origin or composition.
Use gross coin weight, including alloy; enter a positive reading.
Enter the widest edge-to-edge reading in millimeters.
Published reference33.931 g · 32.70 mmAmerican Gold Eagle — 1 oz · $50
Weight differenceEnter both measurementsRelative to published gross weight
Diameter differenceEnter both measurementsRelative to published diameter
Reference fineness916.70‰Specification context only; not measured by this tool.
Enter both measurements to compare them with the selected reference.
Signed difference is measured minus reference. Percent difference is absolute. This worksheet compares numbers only and does not determine a coin's origin or composition.
Selected specification: issuer/reference source.
Calculation method
How the result is calculated
Signed difference = measured value − published reference. Absolute percentage difference = |difference| ÷ published reference × 100. Weight, diameter and source are shown separately.
This is a measurement comparison only. Matching weight and diameter does not establish a coin's origin, composition, condition or issuer; measurement precision, wear and production tolerances also matter.
Evidence and references
Specification sources
Primary references where available
Information only, not investment advice. Theoretical metal value is not a dealer offer, retail price, jewelry appraisal, assay, or guaranteed sale price.