Gap risk calculator
A stop is a price, not a promise. Work out what a trade actually costs when the market opens past your stop and the fill happens wherever there is a buyer.
Loss if price gaps through your stop
−$1521.00
Planned loss−$540.00
Additional−$981.00
Adverse fill1.10090
Multiple of planned2.82×
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The full check runs this against your own rules and tells you what still fits.
What this covers
Any instrument that can gap: everything with a session break, and crypto during thin liquidity.
Models a single adverse open. It does not model a sequence of them.
The gap percentage is yours to choose — this tool does not predict how far price will gap.
Formula and assumptions
Planned loss = |entry − stop| × size × contract value.
Adverse fill = stop moved further against you by the gap percentage.
Actual loss = |entry − adverse fill| × size × contract value.
Assumes the whole position fills at one adverse price. A partial fill sequence can be worse.
Excludes fees and financing.
gap_risk.v1
Worked example
Example — not a prediction.
Position0.90 lots EURUSD short
Entry → stop1.0840 → 1.0900
Planned loss$540
1% gap through stopfill at 1.1009
Actual loss$1,521
Multiple of planned2.8×
Common mistakes
Treating the stop loss as the maximum loss. It is the intended loss.
Holding full size through a weekend or a scheduled announcement at the same risk as a quiet Tuesday.
Sizing so that only a planned loss is survivable, leaving no room for the one that gaps.
Assuming a guaranteed stop covers this — most do not, and the ones that do charge for it.
Limitations
This is arithmetic on numbers you supplied. It does not know your broker, your account, or the market. It does not predict price, does not say whether to take a trade, and is not advice. Maximelion is not affiliated with any broker or prop firm, and nothing here is endorsed by one.
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Last reviewed 25 July 2026