A useful stop loss begins with the price that proves your trade idea wrong—not with an arbitrary percentage. After choosing that invalidation level, you can translate it into account risk, calculate a position size that fits the budget, and select an order type whose execution trade-offs you understand.
A stop is a planned exit, not a guaranteed price
Choose where the trade idea is no longer valid. Decide how much the account can lose there. Then reduce the position size until the price move, fees, and a realistic slippage allowance all fit inside that loss budget.
- Place the stop beyond the level that invalidates the setup, not at a random distance from entry.
- Use account risk to determine position size instead of moving the stop to justify a larger trade.
- Treat the trigger as the instruction to place an exit order; the final fill can be different.
- Invalidation
- The price area where the reason for entering the trade is no longer true.
- Trigger price
- The reference level that activates the stop order.
- Execution price
- The average price at which the activated exit actually fills.
Step 1: choose the invalidation level first
A stop should answer one question: at what price is the original trade idea no longer valid? A long setup may be invalidated below a support level or swing low. A short may be invalidated above resistance or a swing high. The exact method depends on the strategy, but the level should come from the setup rather than the amount of leverage available.
Avoid placing the trigger directly on an obvious line without considering normal volatility, spread, and brief price probes. A small buffer can reduce accidental exits, but a wider stop also increases loss per unit and therefore requires a smaller position.
A calculator cannot choose the correct chart level for you. Its job begins after you select the invalidation: it shows whether the resulting loss fits your account and how the costs change the plan.
Step 2: convert account risk into position size
Decide the maximum planned loss before calculating quantity. The risk percentage is a personal constraint, not a universal rule. It should remain tolerable across a series of losing trades and across all correlated positions open at the same time.
Measure the adverse distance from entry to the expected stop execution, then include entry fee, exit fee, and a slippage allowance. Divide the loss budget by that full loss per unit. This keeps the whole modeled exit—not only the chart movement—inside one budget.
Account balance × Risk percentageEntry price − Estimated stop fillEstimated stop fill − Entry priceRisk budget ÷ (Price risk + Fees per unit)- A wider stop means more loss per unit and a smaller position for the same risk budget.
- A tighter stop allows more units mathematically, but may be more sensitive to normal volatility.
- Higher leverage changes the margin required; it does not reduce the dollar risk created by the same quantity and stop.
- Several positions exposed to the same market move can create more combined risk than each individual budget suggests.
Step 3: choose how the stop should execute
When the trigger is reached, the platform submits the exit instruction you selected. A stop-market order prioritizes getting out, while a stop-limit order adds a price boundary. Neither removes execution risk: market exits can slip and limit exits can remain partly or completely unfilled.
For a protective futures exit, also check reduce-only or close-on-trigger behavior. Without the correct closing instruction, an exchange-specific setup can reject the order or create unintended exposure after another order changes the position.
| Stop type | What happens after trigger | Main trade-off |
|---|---|---|
| Stop-market | Submits a market exit | Higher execution priority; fill price can slip |
| Stop-limit | Submits a limit exit | Price control; execution is not guaranteed |
| Trailing stop | Moves the trigger as price moves favorably | Can protect gains; distance still needs a deliberate rule |
Step 4: check the trigger price and liquidation line
Perpetual exchanges may let you trigger a conditional order from the last traded price, mark price, or index price. These references can diverge during volatility. The trigger basis affects when the stop activates, while the resulting market or limit order still executes against the venue’s order book.
Liquidation is commonly based on mark price. If a last-price stop sits very close to the liquidation level, mark price can reach liquidation first. Compare the stop with the exchange’s current liquidation estimate and leave room for the different trigger references, latency, fees, and slippage.
| Reference | Useful context | Risk to check |
|---|---|---|
| Last traded price | Closest to recent executions | May lag mark price around liquidation |
| Mark price | Common futures risk reference | Can differ from the price used for the final fill |
| Index price | Broader spot-market reference | Can reach the trigger later than the local market |
Worked example: size a BTC long around its stop
Assume a $10,000 account, a maximum planned loss of 1%, a BTC long entry at $68,000, and a technical invalidation at $66,700. Use a 0.02% entry fee, a 0.05% exit fee, and 0.05% adverse slippage on the stop-market exit.
The $100 budget must cover the price loss, both trading fees, and the worse modeled fill. The cost-adjusted result is smaller than a position calculated from the $1,300 chart distance alone.
$10,000 account · 1% risk · BTC long
The stop trigger remains at the chosen invalidation. Position quantity is reduced until the complete modeled loss is approximately $100.
A practical checklist before submitting the stop
Review the complete order after entry and again whenever position size or margin changes. A correct level with the wrong quantity, side, trigger basis, or closing instruction is not a valid risk plan.
- Confirm the symbol, long or short side, and quantity to close.
- Confirm whether the order is stop-market, stop-limit, or trailing.
- Check the trigger basis: last, mark, or index price.
- For stop-limit, leave a deliberate gap between trigger and limit and accept that the order may not fill.
- Use reduce-only or the venue’s position-closing option where appropriate.
- Compare the stop with liquidation after leverage, margin, or position size changes.
- Include fees and a realistic slippage buffer in the planned loss.
- Do not cancel a protective stop unless a replacement risk plan is already ready.
Crypto Stop Loss Calculator
Solve a long or short stop from account risk and position size, or audit an existing trigger after fees and adverse slippage.
Frequently asked questions
What percentage should a crypto stop loss be?
There is no universal percentage. Choose a level where the setup is invalid, then reduce quantity until the loss at that level fits your account budget.
Is a stop-market or stop-limit order safer?
They control different risks. Stop-market prioritizes execution but can slip. Stop-limit controls the worst acceptable limit price but may not execute.
Does leverage change where I should place the stop?
Leverage does not decide the technical invalidation. It changes required margin and liquidation distance, so high leverage can make an otherwise sensible stop impossible to reach before liquidation.
Why did my stop fill below the trigger on a long?
The trigger only activates the order. A sell market order then fills against available bids, which can be lower during a fast move or in a thin order book.
Should I use mark price or last price as the trigger?
It depends on the venue and strategy. Mark price can align the stop more closely with futures risk controls; last price may track local executions more closely. Verify both the trigger rule and liquidation rule.
Can I move a stop after the trade is open?
You can update the plan, but moving a protective stop farther away increases risk. Recalculate the loss and position exposure before making the change.
Exchange mechanics and rates can change. These primary references were used to verify the concepts on this page.
Educational information only. Contract rules and account calculations vary by exchange; verify them before trading.