What does this trade actually cost?
All three venues charge when you buy and none charge when the contract settles.
Kalshi, 100 contracts
| Price | Position | Fee | % of position |
|---|---|---|---|
| 10¢ | $10.00 | $0.63 | 6.3% |
| 25¢ | $25.00 | $1.32 | 5.3% |
| 50¢ | $50.00 | $1.75 | 3.5% |
| 75¢ | $75.00 | $1.32 | 1.8% |
| 90¢ | $90.00 | $0.63 | 0.7% |
Polymarket, by category
| Category | Rate | Max / 100 |
|---|---|---|
| Crypto | 7% | $1.75 |
| Sports, economics, culture, weather | 5% | $1.25 |
| Politics, finance, tech, mentions | 4% | $1.00 |
| Geopolitics, world events | 0 | Free |
Polymarket US, 100 shares
| When | Rate | Max / 100 |
|---|---|---|
| Before Sep 17, 2026 (11:59 PM ET Sep 16) | 6% | $1.50 |
| Sep 17, 2026 onward | 6.95% | $1.74 |
At 50¢ Kalshi charges $1.75. Polymarket charges $1.00 on politics and nothing on geopolitics. Polymarket US charges $1.74 on everything, one rate, no categories.
Rates are read from each venue, not typed. Polymarket sets a market’s rate when it lists it and keeps earlier listings on their original schedule — sports listed before July 2026 carry 3%, listings since carry 5% — so the table shows what a market listed today pays; each market’s own page states its rate. Kalshi’s 0.07 is its published schedule; Kalshi says a few markets carry different fees, and a market’s own order ticket shows its fee. Verified against all three venues on Sep 18, 2026.
ThinBlimp prices every position with this exact module — so the fee you see here is the fee subtracted from the edge you see in the terminal. Convert a contract price to sportsbook odds →
Informational only, not trading advice. Confirm rates against your own fills.
The terminal does this across every market on every exchange at once, and subtracts it from the edge before showing you a number.
Open the terminal →