The three-step method
- Pick your risk per trade. A common range is 0.5% to 1% of the account.
- Let the stop set the size. Lot size = money at risk ÷ (stop distance × value per pip or point per lot).
- Check margin and the daily loss limit. If either one doesn't fit, trade smaller. Don't move the stop closer to make the size fit.
Lot sizes by account size
| Account | EURUSD, 0.5% | EURUSD, 1% | Gold, 0.5% | Gold, 1% |
|---|---|---|---|---|
| $5,000 | 0.12 | 0.25 | 0.05 | 0.10 |
| $10,000 | 0.25 | 0.50 | 0.10 | 0.20 |
| $25,000 | 0.62 | 1.25 | 0.25 | 0.50 |
| $50,000 | 1.25 | 2.50 | 0.50 | 1.00 |
| $100,000 | 2.50 | 5.00 | 1.00 | 2.00 |
The pattern is simple: double the account and the lot size doubles. What doesn't change is the percentage at risk, and that's what keeps you inside the rules.
A shortcut for margin usage
Here's something the tables hide. Once you size by risk, the account size cancels out of the margin sum, and you're left with:
Margin usage = Risk % × Price ÷ Stop distance ÷ Leverage
It works for instruments priced in your account currency, such as EURUSD, gold and NAS100 on a dollar account. Two examples:
- Gold, 1% risk, $5 stop, 1:10: 1% × 4,200 ÷ 5 ÷ 10 = 84%. That breaks an 80% rule on a $5,000 account and on a $100,000 account alike. To stay under 80% you'd need a stop wider than $5.25, or risk under about 0.95%.
- EURUSD, 1% risk, 20-pip stop (0.0020), 1:30: 1% × 1.14 ÷ 0.0020 ÷ 30 = 19%. Lots of room.
The takeaway: tight stops on gold at low leverage are what push funded traders over margin limits, not big accounts.
Worked example: a $50,000 funded account
- Risk 0.75% per trade: $375.
- Gold setup with a $6 stop: 375 ÷ (6 × 100) = 0.625, rounded down to 0.62 lots. Always round down; brokers trade in steps of 0.01.
- Margin at 1:30: 0.62 × 100 × 4,200 ÷ 30 = $8,680, which is 17.4% of the account. The shortcut gives almost the same answer, 0.75% × 4,200 ÷ 6 ÷ 30 = 17.5%. The small gap comes from rounding down to 0.62 lots.
- Daily limit 5% = $2,500, so it would take almost seven full losses to hit it. Plenty of room.
How many losses until the account fails?
| Risk per trade | Losses in a row to lose 5% | Losses in a row to lose 10% |
|---|---|---|
| 0.5% | 10 | 20 |
| 1% | 5 | 10 |
| 2% | 3 | 5 |
Losing streaks of five or six trades happen to good traders. At 2% per trade, one ordinary bad week can end a funded account. At 0.5% to 1%, it's just a bad week.
Where the daily loss limit fits
With a 5% daily limit and 1% per trade, five straight losses end the day. With a 4% limit it's four. If your firm counts open losses, a trade sitting in a big drawdown eats into that allowance before it closes. Plan how many trades you'll take in a day, and size so that your worst realistic day still fits.
What changes after you pass
- At some firms leverage is lower on the funded account, so margin per lot goes up. See how leverage affects margin.
- Some programs add a consistency rule on payouts, which punishes one oversized day. See the consistency rule calculator.
- Your risk per trade shouldn't change. Trade the funded account the way you traded the challenge.
The prop firm lot size calculator runs all three steps at once: it takes your risk, stop, leverage, open trades and daily loss, and gives you the lot size that fits every rule.