Polymarket fees on short-term crypto markets

Each market publishes its own schedule. On crypto markets the fee on a fill is rate × shares × price × (1 − price), with a rate of 0.07.

That curve is a parabola with its peak at 50 cents, which is where the outcome is most uncertain, and it falls to nothing at either end. At the peak it comes to $1.75 per 100 shares — the figure the venue publishes, and the one this site’s accounting is checked against.

Measured against what you actually spend rather than the share count, the whole thing simplifies: the fee is 7% × (1 − price) of the money you put in. Scalping coin flips is the expensive end of this market; buying a near-certainty is nearly free.

Only the taker is charged. A resting order that gets filled pays no fee at all, which means two traders on opposite sides of the same fill can have completely different costs.

Makers are paid on top of that. On crypto markets the venue puts 20% of a market’s taker fees into a pool and splits it between that market’s makers using the same curve the fee is charged on. Because every match has one maker and one taker at the same size and price, the pool arithmetic works out simply: a maker’s rebate is 20% of the fee their own flow would have cost as a taker.

It settles daily in pUSD with a $1 minimum before anything is paid, so a heavy day can show no rebate and the next day show two days’ worth.

Every fill is priced through the published schedule and subtracted from the gross result, which is what makes Trade PnL different from a headline profit number. On markets where the fee can reach 3.5% of a position, ignoring it does not produce an approximate answer — it produces the wrong sign often enough to matter.

One thing public data cannot say is which side of a fill was the aggressor, and only the aggressor pays. PredCheck charges every fill as though it were, so the fee shown is an upper bound and is labelled Estimated. A trader who mostly rests orders paid less, and the maker rebates in their own column are the visible sign of it.

Rebates and rewards are read from the venue’s public payout feed, but they are credited to an account rather than to a market. They are reported beside Trade PnL and never summed into it — the reasoning is in the FAQ, and the full method in about PredCheck.