Grade Upgrade ROI Calculator
Should you send your slabbed coin for regrading? This tool calculates the expected return given upgrade odds, downgrade risk, and fees. Use realised UK auction data to inform your inputs — the answer is rarely “always” or “never.”
How to read this
- GO — expected value comfortably positive. Submit.
- MARGINAL — small expected gain, hinges heavily on probabilities. Worth doing if you're confident in the upgrade odds; skip if you're guessing.
- SKIP — expected value zero or negative. Save the fee.
- Break-even % — the minimum upgrade probability where the math stops favouring submission. Use this as a sanity check on your input.
Realistic upgrade probabilities
- Strong borderline coin (clean fields, good strike, strong eye appeal at the upper edge of current grade): 25-40%.
- Average borderline coin: 10-20%.
- Mid-grade with hidden eye-appeal issues: 5-10%.
- Already top-grade (e.g. MS-67, PR-69): 1-5% — very few coins move from PR-69 to PR-70.
Crossover from one service to another (PCGS → NGC, or vice versa) at the same grade has 80-90% pass rate, so crossover is often the better play if you don't believe an upgrade is realistic but want broader market acceptance.
Worked example
You have a Victorian Old Head sovereign in PCGS MS-63 worth £800 at current realisations. MS-64 examples
sell for £1,400. Resubmission fee is £50. You think there's a 25% chance it'll grade up, 5% it'll come
back lower (worth £680, a £120 loss), and 70% same.
Expected value: 0.25 × £600 + 0.05 × −£120 − £50 = £150 − £6 − £50 = +£94.
Recommendation: GO.