Baseball card values: five sold prices into one usable figure
- The middle three averaged - the figure to use
- $28.67
- All five averaged - what the outlier does to it
- $41.20
- Highest of the five
- $96
- Lowest of the five
- $24
Every figure on this site comes out of the prices you type and the arithmetic printed beside them. There is no feed, no price of our own and no third-party data: this site holds no card prices at all, only the method for reading the completed sales you have already found. Each step is written out on the page so you can check it by hand.
The figures above are a worked example ($28.67). Type the prices you are actually looking at and every line re-computes.
Download the Baseball Card Values and Card Value Checker worked example (CSV)
Type in five recent completed sales of the same card in the same condition. It drops the highest and the lowest, averages the middle three and gives you that figure, alongside the straight average of all five so you can see what the outlier was doing, the high, the low, and the spread between them as a share of the answer. Add your marketplace's selling percentage and what posting costs you and it also shows what you would actually keep. On the worked example five sales of $24, $31, $28, $96 and $27 average $41.20 and the middle three average $28.67; the spread between high and low is 251.2% of that figure, which is the calculator telling you those five sales are not all the same thing.
Where the method behind this calculator comes from
NIST/SEMATECH e-Handbook of Statistical Methods, 1.3.5.17 Detection of Outliers. The method behind dropping the extreme values in a small sample rather than averaging them in. Read 2026-09-11.
eBay, Selling fees. Where the selling percentage this calculator asks for is published. It varies by category, format and account, which is why it is an input here. Read 2026-09-11.
Baseball Card Values and Card Value Checker: the questions readers send about this one
Why drop the highest and the lowest sale?
Because in a sample of five, one result can carry the average further than the other four combined. The high sale is usually two determined bidders and the low one is usually a listing nobody found. Averaging the middle three is a standard robust estimate of where a small sample actually sits.
What if the spread is enormous?
Then the five sales are not five sales of the same thing, and the figure is not trustworthy. Check the parallel, the serial numbering, the condition and whether one was a lot rather than a single card, and replace the odd one out rather than averaging harder.
Should I use asking prices if I cannot find sales?
No. An asking price is what somebody hopes for and completed sales are what somebody paid, and the gap between them in this trade is large. If there are no completed sales, the honest reading is that the market is thin, which is itself the answer.
What selling fee should I enter?
The one on your own marketplace's fee schedule, for your category and your account. This site does not assume a rate, because the rate depends on things only you can see; leave it at zero and the answer is simply the sale price.