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DERIVATIVES / INVERSE CONTRACTS

COIN-M position size calculator.

Size inverse futures by your risk in the settlement coin. Contracts have a fixed USD face value; P&L and collateral are denominated in BTC, ETH or another coin, not USDT.

Inverse USD contractsRisk in coinLong / ShortStop costs & leverageNo live prices
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Looking for the standard linear / USDT-margined model? Open Linear Position Size →

01

Settlement wallet & risk

All balances and estimated P&L here are in the settlement coin, not in dollars.

Collateral that is available in the settlement asset (e.g. BTC), not a USDT balance. This model assumes the entire entered amount is available for this position.
How much of the coin wallet you intend to risk if the stop executes at the modeled price. Choose Coin to enter an absolute amount in the settlement asset. Enter 1 for one percent.
02

Inverse contract & trade

Enter the USD face value of one contract from your exchange specifications.

The actual asset used for margin, commissions and P&L. For BTCUSD inverse contracts, it is typically BTC. Verify your actual futures instrument; this field is a display label, not a live market selector.
Nominal USD value represented by ONE inverse contract (e.g. BTCUSD may use 100 USD per contract on Binance). This depends on the exchange and symbol, so confirm it before trusting the result.
Contract specifications are entered manually

This tool does not load exchange symbols or contract metadata. Verify the USD face value, contract increment, settlement coin and current rules in your exchange's documentation before using the result. Learn how COIN-M contracts work ↗

BTC is the example settlement coin; enter the confirmed contract face value yourself.

Long loses settlement coin when the price moves down to the stop. Short loses coin when the price moves up. The inverse payoff is NOT linear in USD price changes.
Expected fill price in USD for one unit of the settlement coin. No live quote is connected; manually enter the specific instrument price.
Long stop should be below entry; short stop above. A stop order is NOT a guaranteed fill or a liquidation boundary.
Leverage, fees & executionOptional

Assumptions start at 1x leverage, zero fees and zero slippage. These are placeholders, not statements about your actual exchange.

Used only to estimate initial collateral in settlement coin: USD face × contracts ÷ (entry price × leverage). It does NOT change the modeled stop loss for a fixed contract count or predict liquidation.
Estimated taker/maker fee paid in settlement coin at entry: USD notional ÷ entry price × fee rate. Enter 0.05 for 0.05%. Leave blank for zero.
Estimated commission on closing at the modeled stop: USD notional ÷ stop execution price × fee rate. Use the relevant exit order fee, if known.
An additional unfavorable move from the entered stop. Long: lower execution; short: higher execution. Actual slippage can exceed this.
Minimum whole-contract trading increment. We round the size DOWN. Many inverse instruments trade in one-contract steps; confirm the rules on your venue.

Real cross/isolated margin, maintenance tiers, mark price, funding and liquidation remain exchange-specific and are not computed.

Check instrument specifications first. A BTCUSD inverse contract is not the same as a BTCUSDT linear contract. The risk model assumes settlement in the stated coin and a stop fill at its modeled execution price.
HOW AN INVERSE CONTRACT DIFFERS

A dollar face value, a coin outcome.

A BTCUSD COIN-M contract can represent a fixed USD face value, for example $100 per contract on one exchange. The number of contracts is not the number of BTC. Margin, fees, and P&L are denominated in the settlement coin.

The formula below uses C for the confirmed USD face value of one contract, N for the contract count, and E / X for entry/exit prices (USD per coin).

Long P&L (coin) = N × C × (1/E − 1/X)
Short P&L (coin) = N × C × (1/X − 1/E)

To size by risk, the calculator computes the coin-denominated loss per contract at an adverse stop execution, adds assumed coin-denominated entry and exit fees, divides the allowed risk in coin by that loss, and rounds down to whole contracts.

Contracts = floor[ min(risk coin ÷ coin loss per contract, wallet coin ÷ (margin coin per contract + entry fee coin per contract)) ÷ contract increment ] × increment

Approximate margin at entry is N × C / (entry price × leverage) in the settlement coin. Actual venue maintenance margin, hedged positions, cross collateral, liquidation price and funding are outside the model. Importantly, your settlement coin's dollar value can fall while your contract is moving against you.

Formula references: Binance Futures Calculator methodology ↗ and Bybit inverse P&L documentation ↗.

← Switch to linear Position Size

New to inverse futures? Read the illustrated COIN-M guide ↗

INSTRUMENTS / LEARN

New to stablecoin-margined versus coin-margined futures? Understand the different P&L units and collateral requirements.

Compare Spot, USDT-M & COIN-M ↗