Crypto position sizing: let stop distance determine quantity

Crypto position sizing from stop distance starts with a chosen loss budget, then divides that budget by the estimated loss per unit if the exit executes. For a linear position, include the entry-to-stop price difference, trading fees and an explicit execution allowance before rounding quantity down. The result is a planned size, not a guaranteed maximum loss: a stop can slip, remain unfilled or be overtaken by liquidation.

The important output is the quantity you can justify under stated assumptions. A 2% stop does not mean risking 2% of an account, and a leverage setting does not supply the missing quantity. The worksheet below separates the loss decision from the amount bought or sold.

Choose the invalidation level before solving for size

A stop expresses a decision to exit if a defined condition occurs. Start with why that condition would invalidate the trade, then decide whether the resulting exposure fits the account's loss budget. Moving a stop closer merely to make a desired quantity affordable changes the trade's exit rule.

CME Group's position-size lesson identifies the stop location and the amount or percentage of account capital at risk as the two inputs to sizing. That is a planning framework, not evidence that any particular risk percentage or stop distance suits a crypto strategy.

Write the budget in a currency: for example, 50 USDT of modeled loss. If it comes from a percentage, record which equity snapshot supplied the denominator. Total account value, free balance and collateral available to one position can differ. Other open trades also consume the account's ability to absorb losses.

If stablecoin collateral supports that equity, distinguish token units from purchasing power and recognized margin value. The stablecoin collateral stress worksheet separates price, haircut and access shocks that a stop-distance calculation does not capture.

Keep the calculation's units visible

For an unleveraged spot purchase or a linear contract whose exposure is measured in underlying units, define:

• R: the chosen loss budget in quote currency.
• D: the absolute entry-to-stop distance in quote currency per underlying unit.
• C: estimated fees and adverse execution allowance in quote currency per underlying unit.
• Q: underlying quantity, calculated as R ÷ (D + C).

Then apply the venue's permitted quantity increment and recompute the modeled loss using the rounded quantity. A protective long stop belongs below entry; a protective short stop belongs above it. Reject a zero distance or a stop on the wrong side before taking the absolute difference. Borrowing, funding and other holding costs need separate treatment where relevant.

This is a linear payoff calculation. Bybit's USDT-contract introduction illustrates that a 1 BTC contract gains 100 USDT before fees when BTC rises by 100 USDT. Do not transfer that quantity convention to inverse contracts or contracts with a different multiplier. Confirm what one submitted contract or lot actually represents.

Worked example: one budget, three possible stops

All prices, fees, increments and allowances here are hypothetical. They are not current BTC quotes, exchange limits or a recommended allocation.

Assume account equity of 10,000 USDT and a chosen modeled-loss budget of 0.5%, giving 10,000 × 0.005 = 50 USDT. The planned long entry is 60,000 USDT/BTC. Assume a 0.05% fee on both entry and exit, charged in USDT, a 60 USDT/BTC adverse-execution allowance, and an allowed quantity step of 0.001 BTC. The illustration excludes funding and borrowing costs.

For the middle stop at 58,800, the price distance is 1,200 USDT/BTC. The modeled entry fee is 30 USDT/BTC and the exit fee at the stop is 29.40 USDT/BTC. Estimated loss per BTC is therefore:

1,200 + 30 + 29.40 + 60 = 1,319.40 USDT/BTC

Dividing 50 by 1,319.40 gives approximately 0.037896 BTC. Rounding down to the assumed step gives 0.037 BTC. That is 2,220 USDT of entry notional and 48.8178 USDT of modeled loss, approximately 48.82 USDT.

A wider stop supports fewer units under the same budget. A narrower stop permits more units in this arithmetic, which also means more notional, more fees and potentially greater market impact. The table does not show which stop is more likely to succeed.

The exit fee uses the stop price while the allowance covers a worse sale. In this long example, a lower exit also produces a slightly lower percentage fee, making that fee estimate conservative. For a short with a higher assumed exit, calculate its fee at that higher price or otherwise allow for the difference.

The common error hides in the denominator

If the middle example ignores all costs, 50 ÷ 1,200 suggests approximately 0.041667 BTC. Even after rounding down to 0.041 BTC, the same fee and execution assumptions produce 0.041 × 1,319.40 = 54.0954 USDT of modeled loss. That exceeds the chosen budget by about 4.10 USDT.

The opposite error is to treat 50 USDT as the amount to buy. At the stated entry, that purchases only about 0.000833 BTC before fees and rounding. A loss budget measures the intended adverse outcome; entry notional measures the exposure used to create that outcome.

For a leveraged contract, collateral affordability adds another constraint. Initial margin, maintenance requirements and liquidation mechanics must still be checked. The cross-versus-isolated margin ledger identifies which pool may support that position. The loss calculation does not establish that the account can open or maintain the position. The mark-price and liquidation guide explains why the visible trade-price stop and the liquidation reference can differ.

Rounding may leave no acceptable trade

Bybit's instrument-information documentation specifies distinct price ticks, quantity steps, minimum quantities and minimum notionals for its linear and inverse products. Use the current rules for the exact instrument and order type; the example's 0.001 BTC step is invented.

Round quantity down to preserve the modeled budget, then verify the minimum order requirements. If the rounded request is too small, increasing it to the minimum can exceed the loss budget. That is a valid reason to skip the order. The exchange-order-minimums worksheet shows how a feasible quantity can disappear between those two constraints.

Recalculate after any price normalization too. A stop rounded farther away or an entry filled above the assumed long-entry price increases the distance. Reusing the old quantity means reusing a calculation whose inputs no longer match the trade.

A stop budget needs a stress case

The 60 USDT/BTC execution allowance is an assumption. It is not a contractual limit. Bybit distinguishes trigger prices from actual execution prices and documents that rapid changes can create slippage between them.

Suppose the middle example's 0.037 BTC instead exits at 58,000 USDT/BTC. Its price loss is 74 USDT. At the assumed fee rate, entry and exit fees add 1.11 and 1.073 USDT, giving 76.183 USDT total, before any other costs. The actual exit has already embodied slippage, so do not add the planning allowance again. The realized loss would be about 76.18 USDT despite a 50 USDT planning budget.

A stop-limit can leave some or all exposure open when its price condition cannot be met. A stop-market can execute at worse prices and remains subject to venue restrictions. Use the stop-market versus stop-limit comparison for that execution choice and the order-book-depth worksheet to examine how size interacts with available liquidity.

Before submission, retain a compact sizing record: equity observation, loss budget, entry assumption, stop threshold and reference source, fee assumptions, execution allowance, contract units, rounded quantity and stress-case loss. After fills, compare that record with actual exposure and exit coverage. A changed fill, partial entry or manual addition is a reason to review the calculation again.

Editorial method: Prepared with AI assistance on 23 October 2026 from the primary sources linked above. The original worksheet and gap scenario are constructed teaching examples; arithmetic and units were checked. No live trade, recommended risk percentage or KLINEO sizing feature is represented.