CoinGuideApp tests coin reference apps for collectors working through a series — Lincoln cents, Mercury dimes, Morgan dollars — who want to understand every key date, every variety, and every grading decision, not just scan a coin once and move on.
Who We Are
Three of us started this because we were halfway through a Mercury dime set when we realized our favorite app couldn't tell us why one 1916-D looked different from another, or what SMS (Satin Matte Surfaces) meant for grading. We tried six reference apps over six months and found they were built for identification, not for series learning. One of us has been collecting Lincoln wheat cents for eight years; another returned to coin collecting after a twenty-year break. We needed a guide, not a scanner.
CoinGuideApp exists because series collecting — the real kind, where you're hunting for that 1909-S VDB or learning the Proof-only dates — demands an app that grows with you. We test reference apps on whether they actually teach you a series, whether they show you the tricky varieties, and whether they explain why a Proof strike or an SMS strike changes everything about how you grade and what you'll pay. That's what we look for.
Methodology
We build a test set of 38 coins across four major US series: Lincoln wheat cents (1909–1958), Mercury dimes (1916–1945), Morgan dollars (1878–1921), and state quarters (1999–2008). Within each series, we include common dates, key dates, a Proof strike, an SMS example where applicable, and at least one variety that trips up casual collectors — the 1916-D Mercury with the doubled die, the 1921 Morgan Peace transition, the 2004-D Wisconsin extra leaf quarter. We spend three months working through each app: fifteen hours per app per month, testing whether the app can walk us through our series without requiring the internet every time, whether it shows us the exact diagnostic for a variety, and whether it explains what strike type we're looking at. We re-test quarterly and after each major app update.
Our scorecard looks at five things: strike type differentiation (can the app explain the difference between a business strike and an SMS?); variety depth (does it show us obscure doubled dies or planchet errors, or just common dates?); series continuity (does it let us track what we have vs. what we're missing in a single series?); grading guidance specific to strike type; and offline reference capability (can we look up a date without WiFi?). We don't score apps by counting how many coins they have in their database — we score them on whether a collector actually uses the app to finish a series.
Our Standards
We believe an app built for series collectors has to show you the rare-strike scenarios and explain why they matter. Most reference apps treat every Mercury dime strike the same — they'll tell you the date and mintmark, but they won't explain that a Proof-only 1938 exists, or why an SMS surface can throw off your grading estimate by two grades. We score apps on whether they give you coin-specific diagnostics: not just 'check the reverse field finish' but 'on a 1932 Proof, SMS surfaces should show frosted devices and mirror fields; a reverse clash will show a doubled olive branch.' We look for apps that help you narrow down which variety you have, not apps that force you to guess. If an app doesn't handle the edge cases — the mintmark varieties, the proof-only issues, the subtle strike differences — it fails our test, no matter how polished the interface. We also value apps that admit uncertainty. If the user cannot tell whether a 1921 Morgan is a Peace or Peace transition type, a good app should show both possibilities with a range, not force a yes-or-no answer. That honesty about variety is what separates a reference tool from a guessing game.
Disclosure
We do not accept paid placement or sponsorship from app developers; we do not review an app we have not used for at least twelve weeks across a full test series. We do not score apps based on whether they claim to detect every variety ever minted — we score them on whether they help a collector actually work through a series without confusion; a reference app that admits 'I cannot distinguish this 1921 Morgan as Peace or transitional' is more useful than one that guesses and misleads. We do not test or review world coins, ancient numismatics, or US commemorative series beyond the major circulation and Proof US series; our expertise is modern US collector coins, not the entire range of numismatic possibility.
Contact
If you are building a coin reference app and want our review, or if you have a series you think we should test next, we would like to hear from you. Contact the team using the form on the site.