Your position size should never be a guess. Enter your account, the percentage you're willing to risk, and how far away your stop is — and this calculator gives you the exact size to trade.
Position size calculator
For most USD-quoted forex pairs the pip value per standard lot is about $10. For JPY pairs, indices and futures it differs — check your instrument and adjust the field. This tool is for education, not advice.
The formula behind it
There's no magic here — just one line you should know by heart:
Work it through with the defaults above: a $5,000 account risking 1% is $50. With a 25-pip stop and $10 pip value, that's $50 ÷ (25 × 10) = 0.20 lots — two mini lots, or twenty micro lots. Widen the stop and the size shrinks; tighten it and the size grows. Your dollar risk stays fixed at $50 either way. That's the whole point.
Why size from risk, not from conviction
New traders size up when they "feel sure." That's exactly backwards. Conviction doesn't change the odds of a single trade — it just makes the loss bigger when you're wrong. Sizing from a fixed risk rule means no single trade can take a meaningful bite out of your account, no matter how confident you were.
If you want the deeper background on the units themselves, read What Is a Lot Size? first. Then pair this with a defined risk-to-reward ratio so every trade has a planned downside and a planned upside.
Quick reference
| Account | Risk 1% | Stop 20 pips | Lot size |
|---|---|---|---|
| $2,000 | $20 | 20 pips | 0.10 lots |
| $5,000 | $50 | 20 pips | 0.25 lots |
| $10,000 | $100 | 20 pips | 0.50 lots |
| $25,000 | $250 | 20 pips | 1.25 lots |
Save the calculator, run it before every trade, and let your size be the boring, mechanical part of your process. The exciting part — the setups — is what we do together in the room.