What is coin grading?

The short answer

Coin grading is the assessment of how much wear and how many marks a coin carries, expressed as a number from 1 to 70 on a scale the whole trade prices against. A grading service seals the coin in a tamper-evident holder with that number on it, which turns one person’s opinion into something a buyer will pay against without seeing the coin.

What the number measures

The scale runs from 1, a coin worn until only the outline of the design survives, to 70, a coin with no wear and no mark visible at ten times magnification. It was built for early American copper, where collectors needed to price the difference between a barely readable cent and a slightly readable one, and the trade extended it to everything.

Above 60 the coin never circulated, and the prefix changes to say how it was made: MS for mint state, a coin struck for circulation that never went into it, and PR or PF for proof, a coin struck twice on polished dies for collectors. MS65 is a mint state coin with a handful of small marks. MS63 is the same coin with more of them.

Who assigns it

Anyone can state a grade, and what they are stating is an opinion. Four grading services carry weight in the United States market: PCGS and NGC are the two the trade prices against, with ANACS and ICG behind them. They examine the coin, authenticate it, assign a grade and seal it in a plastic holder with a certification number that can be looked up.

The holder is doing something specific. It lets a coin be bought by someone who has not seen it, priced against published sales of the same coin at the same grade, and sold again without the argument starting over. That is the whole product, and it is why the same coin raw and graded fetch different money.

What a grade cannot do

A grade is not a valuation, and no grading service issues one. It says what the coin is; what it is worth is set by what the last few examples sold for, which moves with the market and with how many have been graded since.

A grade also does not rescue a coin that has been altered. A cleaned, polished, repaired or environmentally damaged coin comes back in a holder marked with that fact instead of a number, and it is priced accordingly. Cleaning a coin is the way most people produce that outcome without meaning to.

When it is worth paying for

Grading costs a fee per coin, and it is worth paying when the fee is small against the difference it makes: a coin whose value turns on a judgement call, a coin scarce enough to be worth faking, or a coin heading to an auction where bidders cannot handle it. On a common circulated coin the fee exceeds the coin, and the trade will price it across a counter in seconds for nothing.

Should I get my coin graded works through the decision with the numbers in front of you, and does condition affect a coin’s value covers what the grade is measuring before you pay anyone to measure it.