Baseball card price guide: why the guide price and the sale price disagree
- 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
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.
A price guide gives one number for a card. A run of completed sales gives a spread, and the difference between the two is not an error in either: they are answering different questions. This page sets out what a guide price is, what a sold price is, and how to get from a screen full of completed sales to a single figure you can act on without being led by the one result that does not belong.
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Understand what a guide price is measuring
A guide price is an editor's figure for a card in a stated condition, set on the publisher's schedule rather than on the day you are looking. It is useful for orientation across thousands of cards at once, and it is the wrong instrument for the single card in your hand, because your card's condition, its exact parallel and the week you are selling in are all outside it.
Collect five completed sales, not listings
An asking price is what somebody hopes for; a completed sale is what somebody paid. Take five recent completed sales of the same card, in the same condition and the same holder or lack of one, and write the prices down. Fewer than five and one odd result dominates; many more and you start reaching back into a different market.
Drop the highest and the lowest, and average the rest
The high sale is usually two determined bidders and the low one is usually a mis-titled listing nobody found. Dropping both and averaging the middle three is a standard robust estimate of the middle of a small sample, and it is what the calculator on this page does. On its worked example the five sales are $24, $31, $28, $96 and $27: all five average $41.20, the middle three average $28.67, and the whole of that 44% gap is one sale.
Look at the spread before you trust the answer
The calculator prints the high, the low and the spread between them as a share of the middle-three figure. A tight spread means the market agrees and the figure is solid. A wide one means your five sales are not the same card in the same condition, and the honest move is to go back and pick better comparables rather than to average harder.
Baseball card price guide: the questions readers send about this one
Is there a free baseball card price guide?
There are several, and all of them give you an editor's number rather than a sale. Completed sales are free to read on any marketplace that publishes them, and this site's calculator turns a handful of those into one figure without charging or asking for an account.
Why is the guide price so much higher than what cards actually sell for?
Usually because the guide is quoting a higher condition than the card in front of you, and because a guide figure is set on a schedule while sales happen daily. Neither number is wrong; they are measuring different things, and only one of them is what somebody paid.
How many completed sales do I need?
Five is enough for the middle-three method to do its job and few enough to keep every sale recent. With three you cannot drop anything; with twenty you are averaging across weeks in which the market may have moved.
What if all five sales are wildly different?
Then they are not five sales of the same thing. Check the parallel, the serial numbering, the grade and whether one was a lot rather than a single card. A wide spread is information about your comparables, not about your card.