How to read our numbers
About our prices
A card’s price can jump because of a single odd sale. Here’s what each number on CardStack means and how we try to stop one-off sales misleading you.
Market Price
The main price on every card is the TCGplayer Market Price in US dollars, from the Pokémon TCG API. TCGplayer works it out from recent completed sales on its US marketplace, averaged over several transactions, not from asking prices. Where a card has more than one print (for example normal and reverse holo), the headline price is the highest-priced print unless you pick one.
It’s a good guide, but it isn’t perfect: a card that rarely sells can move a long way on one sale, and our source only refreshes the prices every few days. The date under each price list shows when the source last updated them.
7-day and 30-day median
Every morning we save a snapshot of every card’s headline price. The median is the middle value of those daily prices over the last 7 or 30 days, so a single spike or dip can’t drag it far. If the source didn’t update its prices between two of our snapshots, we count that data once, so repeats don’t make a price look steadier than it is.
We only show a median once there are at least 3 different daily prices in that window. Until then you’ll see “median builds after a few days”.
Volatile
We add a Volatile badge when a card’s price has been swinging a lot in our snapshots from the last 30 days. Either:
- The prices are spread out
- At least 5 daily prices, and their typical distance from the average (the standard deviation) is more than 20% of the average. Statisticians call this the coefficient of variation.
- Or there was one big jump
- The price moved more than 40% between two snapshots in a row, and the higher of the two prices was at least US$5. The US$5 floor stops cheap cards being flagged for moving from 20 to 30 cents.
A Volatile price may be skewed by a one-off sale, so lean on the median and check recent sold listings before you buy or sell.
How many copies are selling?
We’d like to warn you when a card trades thinly, but our price source gives no sales or listing counts, so we don’t show a guess.
Your currency
Prices start in US dollars. When you choose another currency we convert at the latest reference rate (normally the European Central Bank’s, via Frankfurter), so converted prices are approximate. Medians are worked out in US dollars and converted the same way.
Prices are for information only and aren’t financial advice. Source of every price: TCGplayer Market Price via the Pokémon TCG API (Scrydex).