The Same Trade, Different Cash Flows
These are **hypothetical examples, not live quotes**: 100 contracts bought in one fill at 40 cents, then either sold in one fill at 60 cents or held to settlement. They assume no rebates, promotions or intermediary charges and begin with cleared account cash. Funding, withdrawals and taxes are separate.
For a concrete contract type, consider a full-game football-winner contract on the same team and game. Polymarket US’s sports rules and Kalshi’s football terms both include overtime by default. The examples cover an ordinary completed game with a winner: the winning contract pays $1 and the losing contract pays $0.
If the taker buyer holds a winner instead of selling early, the $100 settlement payment leaves a profit of $58.33 on Polymarket US or $58.32 on Kalshi. A losing settlement pays nothing: the loss is the full $41.67 or $41.68 entry cost. The early-sale and settlement scenarios are alternatives, not payments to add together.
The standard taker formulas are similar: **0.0695 × C × p × (1 − p)** on Polymarket US and **0.07 × C × p × (1 − p)** on Kalshi for a multiplier-one market. Here, C is contract quantity and p is the dollar price. Polymarket US rounds to the nearest cent using half-to-even rounding. Its table-tennis and combo schedules differ; Kalshi also lists market-specific exceptions.
Resting Orders Change the Bill
A taker removes an available order; a maker leaves an order resting for someone else to trade against. Merely choosing a limit order does not guarantee maker treatment if it immediately matches.
Polymarket US’s Tier 1 maker receives no rebate and pays no maker trading fee. Kalshi’s schedule applies a maker coefficient of 0.0175 to its professional-football-game series. For the same hypothetical 100-contract purchase at 40 cents, that means $40 paid on Polymarket US versus $40.42 on Kalshi.
If both entry and exit qualify as maker fills, selling at 60 cents returns $60 on Polymarket US and $59.58 on Kalshi, producing profits of $20 and $19.16. If held instead, normal winning settlement produces profits of $60 and $59.58; a losing settlement loses $40 and $40.42. These maker prices are assumptions, not promised fills. Kalshi does not charge maker fees in every market, while higher Polymarket US tiers can receive rebates.
Price, Rules and Moving Money
The spread is the gap between the best buying and selling prices. A market buy takes the ask; a market sale takes the bid. Available size matters too: if the best price cannot fill the entire order, the remainder can execute at worse levels. That can outweigh the one-cent taker-fee difference in this example.
Matching the team name is not enough to establish equivalent contracts. Kalshi’s football terms generally require a postponed game to start within 48 hours of its original date; Polymarket US’s guidance allows rescheduling before contract expiration, typically two weeks from the original event date. Compare the particular market’s period, outcome source, tie and cancellation terms before comparing costs.
Moving money is a separate bill. Kalshi’s schedule lists no ACH deposit or withdrawal fee, a maximum 2% card-deposit fee, and possible third-party processor charges for crypto transfers. Polymarket US describes cash withdrawals as free; funding-method charges should be checked separately before depositing rather than assumed to be included in the trading examples.
Cash proceeds are not necessarily immediately withdrawable. Polymarket US says deposits must fully clear before withdrawals, typically taking three to four business days, including proceeds from trades tied to those deposits.
