Stop Loss Calculator
Calculate a stop price for a long or short stock position from a percentage distance or cash loss cap.
Compare the mathematical level and the level aligned to a supplied price increment.
Modeled stop price and loss
Enter your trade assumptions or load the worked example.
The calculation assumes the entire position exits at the shown price. Actual fills can differ and losses can exceed the modeled amount.
Learn to calculate a stop price
Follow worked long and short examples, including how rounding affects the modeled loss.
Read the stop loss guideFormula and methodology
Stop = entry − distance for a long, or entry + distance for a short.
Stop = entry − distance for a long, or entry + distance for a short. In percentage mode, distance is entry times the supplied percentage divided by 100. In cash-cap mode, distance is cap minus charges, divided by quantity. Multiply price distance by shares and add charges to obtain modeled loss. Align a long stop up or a short stop down when an increment is supplied.
Definitions
The stop price is a hypothetical exit level on the loss side of entry. A percentage distance measures the move relative to entry. A cash cap includes the stated round-trip charges. The optional price increment sets the spacing of a grid anchored at zero.
Verified worked examples
For 20 long shares at 50, a cash cap of 53 and charges of 4 leave 49 for the price move. The distance is 2.45 and the mathematical stop is 47.55. A 0.10 grid gives 47.60, with modeled loss of 52 and unused cap of 1. The next farther level, 47.50, would cost 54.
Interpretation
An aligned level is the farthest grid price that stays within the requested distance and remains on the loss side of entry. If the increment leaves no such price, the mathematical result remains available. Cash headroom is the cap less the modeled loss at the aligned stop.
Inputs and interpretation
Choose long or short and a calculation mode. Supply the entry, positive share quantity, distance or cap and explicit round-trip charges. Enter zero charges if none apply. Optionally enter the price increment. Switching modes clears the distance or cap field.
Assumptions and limitations
The entire stock position exits once at the shown price. Apply the same stated charges to either mathematical or aligned scenario. Use one major currency throughout. The selected market changes formatting.
Supported domain and common mistakes
Inputs support 12 decimal places. Prices, quantity, cap, charges and increment are bounded by 1 trillion, and the percentage is positive and at most 100. The resulting stop must be positive, strictly adverse and at most 1 trillion. A mathematical price may be rounded to 24 significant digits for display. The grid and modeled losses use unrounded values.
Use the position entry price for the percentage. A price distance of 2% does not imply losing 2% of account equity. Rounding to the nearest grid price can move a stop farther from entry and increase modeled loss.
Frequently asked questions
How do I calculate a stop price from a percentage?
How does the calculator account for fees?
Why is there no grid-aligned stop?
What if my cash cap equals my charges?
Can I use fractional shares?
Does a cash cap limit my actual loss?
Sources and educational scope
Educational scenario analysis. Actual fills may differ or fail to occur, so realized loss can exceed the modeled loss. The tool excludes broker tick schedules, execution eligibility, borrowing, FX and taxes. It gives no personalized recommendation.
Reviewed . AI-assisted content under operator editorial responsibility. No independent expert financial review is claimed.