CREDITOFFICER.COMNumisNook

Coin Tools & Calculators

Free, practical tools for coin collecting — grade reference, rarity classification, holder sizing, metal-content weight, die-variety identification, and storage guidance. Collecting and history only — no valuation, price guides, or investment advice.

Coin Grade Guide

Look up any point on the Sheldon 70-point scale, from Poor to Perfect Mint State and Proof, and see what that grade generally looks like

Mintage & Rarity Scale Lookup

Classify a coin's rarity on the R-1 to R-8 scale from its estimated surviving population — a different question from its original mintage

Coin Holder & Album Size Finder

Enter a coin's diameter in millimetres and find the nearest standard 2x2 flip, capsule, or album-slot size

Coin Metal Weight Calculator

Break a coin's total weight down by its known alloy composition, in grams per metal — a composition breakdown, not a valuation

Die Variety & Error ID Helper

Select the physical symptoms you observe and see which named die variety or mint error category they resemble

Coin Storage & Humidity Guide

Turn a storage space's relative humidity and volume into a plain-language risk read and a rough desiccant amount

Coin Specification Reference

Diameter, alloy composition, expected weight breakdown, and matching holder size for common US coin types and eras, in one table