Position Size Calculator
Turn your risk per trade and stop distance into an exact lot size — works for forex, metals, energy and index CFDs, with fully editable contract specs.
What it is
A position size calculator answers the most important number in every trade: how many lots to open. The logic is "risk first, size second" — you decide the maximum percentage of your account you are willing to lose on one trade (a common convention is 1%–2%), then combine it with your stop-loss distance to work backwards to a lot size that keeps the loss within that limit. Oversized positions are one of the fastest routes to a deep drawdown; fixing your per-trade risk at a small percentage leaves enough room to survive a losing streak and wait for the next setup.
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Calculate your position size
Enter your account, risk per trade and stop distance — get the lot size instantly.
Contract size = quantity per lot: forex 100,000 (base currency), gold 100 (oz), oil 1,000 (barrels), major indices 1 (index unit). Verify in the MT5 symbol specification window — editable anytime.
The quote currency differs from your account currency, so one rate is needed. The tool never fetches prices online — results use the rate you enter.
Contract sizes and quote currencies are typical defaults and editable. Most reliable: in MT5, right-click the symbol → Specification; leverage and balance follow your account.
Suggested size
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Exact size
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Risk per lot (over this stop distance)
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Risk amount
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Actual risk (rounded)
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How to use it
- Pick a symbol: the dropdown comes with common presets (contract size and quote currency pre-filled with typical defaults), or choose "Custom" to enter your own;
- Enter your account size and risk per trade: as a percentage (e.g. 1%) or a fixed amount;
- Enter the stop distance: the price difference between entry and stop, in quote currency (gold from 2650.00 stopped at 2647.50 → enter 2.50);
- Pick the account currency: when the quote currency differs from your account currency, enter a current exchange rate as prompted;
- Read the result: the suggested lot size is rounded down to two decimals, and the actual risk after rounding is shown.
The formula
The calculation has three steps: convert the risk into money, find what one lot loses over your stop distance, then divide the two.
The stop distance is entered as a price difference in the quote currency — no pip conventions: decimal and pip definitions differ per symbol and broker, while a price difference is unambiguous. The exchange rate is entered as "1 account currency = ? quote currency" (e.g. with a USD account and USDJPY, enter 153.62). The result is rounded DOWN to two decimals — rounding up would let the actual risk exceed your planned percentage.
Worked example
The most common setup, as an example: a USD account trading EURUSD.
- Account 10,000 USD, risk 1% per trade → risk amount = 100 USD;
- EURUSD contract size 100,000, stop distance 0.0050 (bought at 1.0850, stopped at 1.0845) → risk per lot = 0.0050 × 100,000 = 500 USD;
- Position size = 100 ÷ 500 = 0.2 lots.
With 0.2 lots and a 0.0050 stop distance, the worst case for this trade is a 100 USD loss — exactly 1% of the account.
FAQ
Q How much should I risk per trade?
A widely used convention is 1%–2% per trade: even several consecutive stop-outs leave the account intact and your decisions unemotional. The right number depends on your own strategy and tolerance — this tool only converts your percentage into lots and does not constitute investment advice.
Q Why is the suggested size rounded down?
Lot precision is limited by your broker's minimum step (usually 0.01). Rounding to the nearest can push the actual risk slightly above plan, so this tool always rounds down and shows both the exact size and the actual risk after rounding, letting you decide.
Q What is the contract size for gold, oil or indices, and how do I fill the stop distance?
Contract sizes vary meaningfully between brokers (gold is commonly 100 oz per lot; index CFDs map one lot to different index units). Presets use typical defaults and remain editable — the reliable way is to check your MT5 symbol specification window (right-click the symbol → Specification) and enter the exact values. The stop distance is the price difference in quote currency: gold bought at 2650.00 with a stop at 2647.50 → enter 2.50.
Q Why is the stop distance not in pips?
Pips depend on decimal conventions: gold is quoted with either 2 or 1 decimal depending on the broker, and index CFD "pips" differ per broker — the same distance described in pips can mean 10x different things. A price difference (like 2.50) is never ambiguous; it is also the standard used across this toolbox's profit, margin and swap calculators.
Q Why is an exchange rate needed sometimes?
The risk per lot is first computed in the quote currency (e.g. USDJPY per-lot risk is in yen). Converting it to your account currency needs a current rate. This tool does not fetch prices online — you enter the rate as prompted (format: 1 account currency = ? quote currency), so the result is always based on a price you accept.
Q Does the result guarantee profitable trading?
No. Position sizing only limits how much a single loss can take from your account; it predicts nothing about direction and guarantees nothing. Stops can slip or gap through, and the realized loss may exceed the calculated value.
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Download Camovia TrayResults are for reference only and do not constitute investment advice. Preset contract sizes and quote currencies are typical defaults — the values at your broker and platform prevail; spreads, gaps and slippage may cause actual results to differ.