How do I calculate a stop-loss price?

Long: stop = entry × (1 − stop %), or entry − k × ATR. Short: stop = entry × (1 + stop %), or entry + k × ATR. Example: a long entry at $50 with a 5% stop gives $47.50; with ATR = $1.20 and k = 2 the stop is $50 − $2.40 = $47.60.

How is position size calculated from the stop?

Position size = money at risk ÷ stop distance per unit. With a $10,000 account, 1% risk ($100) and a $2.50 stop distance you can buy 40 shares. If fees are $5 round trip, only $95 is left for price risk, so the size is 38 shares. The calculator rounds down so the loss never exceeds the plan.

What is an ATR stop loss?

The Average True Range measures how far a market typically moves in one bar (usually a 14-period average). Placing the stop a multiple of ATR away — commonly 1.5 to 3 × ATR — keeps it outside normal noise, and a wider stop automatically means a smaller position for the same dollar risk.

What percentage should I risk per trade?

Many trading educators suggest risking about 0.5% to 2% of the account per trade, so that a normal losing streak does not do lasting damage: ten consecutive 1% losses leave about 90.4% of the account, while ten 5% losses leave about 59.9%. This is general education, not a recommendation for your situation.

What is the break-even win rate?

With a reward-to-risk ratio R (target distance ÷ stop distance), you break even before costs when you win 1 ÷ (1 + R) of your trades. At 1:1 that is 50%, at 1:2 it is 33.3% and at 1:3 it is 25%.

How does a trailing stop work?

A trailing stop follows the price at a fixed distance — a percentage, a dollar amount or a multiple of ATR — but only in your favour. For a long trade, stop = highest price since entry − trail distance; it never moves down. Once the trailing stop is above entry, the trade has locked in a profit if it is hit (ignoring gaps).

Does this work for forex or crypto?

Yes, the arithmetic is the same for any instrument priced per unit. For forex, enter prices and turn off whole-unit rounding to size in currency units, then divide by 100,000 for standard lots (or 10,000 for mini, 1,000 for micro lots); the pip value calculator handles accounts in a different currency.

Is a stop loss guaranteed?

No. A standard stop becomes a market order when triggered, so a gap or fast market can fill you well beyond the stop price. Guaranteed stops (offered by some brokers for a fee) are the exception. Treat the calculated loss as the planned loss, not a maximum.

Stop Loss Calculator

Enter account size, risk per trade and entry price, then set the stop by percentage, price or ATR multiple. You get the stop price, whole-unit position size, the money actually at risk, R-multiple targets, the break-even win rate and a trailing-stop level — for long or short trades. Educational only, not financial advice.

Educational tool, not financial advice. It does arithmetic on the numbers you enter. Stops can fill worse than planned in gaps or fast markets.

Trade Parameters

Direction

Account size ($)

Risk per trade (%)

Entry price ($)

Fees, round trip ($)

Stop loss method

Stop loss (%)

Target price ($) (optional)

Round down to whole units (shares)

Stop Loss Price

—

Position Size

—

units

Money at Risk

—

loss if stopped

Trade Summary

Reward targets

Target	Price	Profit	Break-even win rate

Trailing stop

Trail by

Trail amount

Highest price since entry

Risk per trade and losing streaks

Account left after consecutive full-risk losses (each loss is a % of the remaining balance), and the gain needed to get back to the start.

Risk / trade	After 5 losses	After 10 losses	Gain to recover (10)
0.5%	97.5%	95.1%	+5.1%
1%	95.1%	90.4%	+10.6%
2%	90.4%	81.7%	+22.4%
3%	85.9%	73.7%	+35.6%
5%	77.4%	59.9%	+67.0%
10%	59.0%	34.9%	+186.8%

Results copied!

Summary

A stop-loss calculator answers two questions: where should the stop go, and how big can the position be so that hitting the stop loses only the amount you planned? For a long trade the stop sits below entry (entry × (1 − stop %), or entry − k × ATR); for a short it sits above. Position size = (account × risk %) − fees, divided by the distance between entry and stop, rounded down to whole units. The calculator also shows the position value against your account, target prices at 1R, 2R and 3R, the break-even win rate for your reward-to-risk ratio (1 ÷ (1 + R)), and where a percentage, dollar or ATR trailing stop would sit after the price moves in your favour. It is an educational tool and not financial advice; real fills can be worse than the stop price because of gaps and slippage.

How it works

Choose long or short and enter account size, risk per trade (%) and entry price.
Set the stop: a percentage from entry, a fixed stop price, or a multiple of the Average True Range (ATR).
Optionally add round-trip fees, a target price, and whether to round to whole units.
Position size = (account × risk % − fees) ÷ |entry − stop|, rounded down; the money actually at risk is recalculated after rounding.
Read the R-multiple targets, break-even win rate and, in the trailing-stop panel, the stop level for the best price reached so far.

Use cases

Equity traders sizing positions to keep risk below 1% or 2% of their account.
Swing traders placing volatility-based stops at 1.5–3 × ATR.
Short sellers working out a buy-stop above entry and the matching size.
Crypto traders determining unit quantity for a volatile asset entry.
Beginners learning the relationship between account risk, stop distance and position size.
Planning where a trailing stop will lock in profit as a trade moves.

Frequently Asked Questions

Last updated: 2026-10-10 · Reviewed by Nham Vu