Lot size formula
Lots = Risk in money / (Stop loss in pips × Pip value per 1 lot)
Risk in money is the balance times the risk percentage divided by 100. Pip value per lot is the contract size times the pip size, converted into the account currency.
Example
| Step | Calculation |
|---|---|
| Risk in money | $10,000 × 1% = $100 |
| EURUSD pip value per lot | 100,000 × 0.0001 = $10 |
| Stop loss | 20 pips |
| Position size | 100 / (20 × 10) = 0.5 lots |
The same risk with a 50-pip stop is 0.2 lots: the wider the stop, the smaller the position, while the loss when the stop is hit stays the same — $100.
Pip value by instrument
| Instrument | 1 pip | Value per lot |
|---|---|---|
| EURUSD, GBPUSD, AUDUSD, NZDUSD | 0.0001 | $10 |
| USDJPY, EURJPY, GBPJPY | 0.01 | ¥1,000 — about $6.67 at USDJPY 150 |
| USDCHF, USDCAD | 0.0001 | 10 francs or 10 Canadian dollars |
| EURGBP | 0.0001 | £10 |
| XAUUSD, 100-ounce contract | $0.1 | $10 |
| XAGUSD, 5,000-ounce contract | $0.01 | $50 |
When the quote currency differs from the account currency, the pip value is converted at the current rate: for USDJPY on a USD account it is divided by the USDJPY rate, for EURGBP it is multiplied by GBPUSD. The calculator tells you which rate it needs.
Pips and points
With five-digit quotes a point is the last digit of the price: 0.00001 for EURUSD, 0.001 for USDJPY. A pip is ten points. A «200 points» stop in MetaTrader is 20 pips. The calculator accepts the stop in either unit.
Why the size is rounded down
Brokers accept volume in steps — usually 0.01 lots. Rounding up would make a stopped-out trade cost more than your risk. So the calculator rounds down and shows the actual risk of the resulting size.
Skip the manual calculation
In Davinchu the MetaTrader 5 risk manager — the T-Manager EA — sizes positions from risk right on its panel: enter the risk in money or percent and set the stop. The «Risk per trade» limit from the dashboard blocks entries without a stop or with risk above the limit. More on the «MT5 risk manager» page.