To size a prop firm trade, decide how much of the account you will risk (for example 0.5%), enter your stop distance, and divide the risk in dollars by what one lot or contract loses at the stop. On a $100K account, 0.5% is $500; with a 20-pip stop on EUR/USD (about $10 a pip per lot) that is 2.5 lots. The free position size calculator does this for forex, CFDs, gold, futures and crypto in one place, and shows how many losing trades in a row you can take before the daily loss limit.
What is a position size calculator?
A position size calculator turns a risk rule into a size you can type into your platform. You tell it how much you are ready to lose on one trade and where your stop loss is, and it gives the lots (forex and CFD), contracts (futures) or position value (crypto) that lose exactly that much if the stop is hit. It rounds down to the step your platform accepts (0.01 lot, or 1 contract), so the real risk is never above your plan.
It does not tell you where to enter or exit. It only keeps one trade from being bigger than you meant.
How do you use the calculator, step by step?
- Pick your market. The buttons are Forex & CFD, Futures and Crypto, matching the three kinds of prop firm.
- Enter your account size. Type it or use the slider ($5,000 to $400,000).
- Set your risk per trade. A percentage of the account, with a slider from 0.1% to 3% and quick buttons.
- Choose what you trade. For forex and CFDs, pick the pair, gold, silver or another CFD. For futures, pick the contract. For crypto, enter your entry price and your stop price.
- Enter the stop loss. In pips for forex, in dollars of distance for metals, in points for futures.
- Enter your firm's daily and maximum loss limits in percent. They differ by firm and by account; find yours on the firm's page in our prop firm reviews.
- Read the result. "You risk" is what you lose if the stop is hit. The size is what to type into your platform.
Two extras help you judge the trade. "What if" shows the same trade at other risk levels, with how many losses in a row each can take before the daily limit. The runway chart draws your balance falling after each losing trade, with a line at the daily limit.
How do you calculate lot size for forex on a prop firm account?
The formula is: lots = risk in dollars ÷ (stop in pips × value of one pip per lot). A standard lot is 100,000 of the first currency, and a pip is 0.0001 (0.01 for yen pairs). On EUR/USD a pip is worth $10 per lot. For pairs not quoted in dollars the calculator turns the pip value into dollars at today's rate, which you can change.
Worked example, $100K account: risk 0.5% = $500. Stop 20 pips on EUR/USD. Loss per lot at the stop = 20 × $10 = $200. Size = $500 ÷ $200 = 2.5 lots.
The same account at 1% risk with the same stop is 5 lots. Risk doubles, so size doubles.
How do you size a gold (XAU/USD) trade?
For metals the calculator asks for the stop as a distance in dollars. One lot of gold is 100 ounces, so a $1 move is $100 per lot.
Worked example, $50K account: risk 0.5% = $250. Stop $5 away. Loss per lot at the stop = 5 × $100 = $500. Size = $250 ÷ $500 = 0.5 lots.
How do you calculate the number of futures contracts?
For futures the calculator uses the dollar value of one point for each contract, from the exchange's specs: ES is $50 a point, NQ $20, and the micro contracts one tenth of those (MNQ $2). Contracts = risk in dollars ÷ (stop in points × dollar value of one point). It rounds down to whole contracts.
Worked example, $50K account, Micro Nasdaq: risk 0.5% = $250. Stop 20 points. Loss per contract = 20 × $2 = $40. Size = $250 ÷ $40 = 6.25, so 6 contracts (a real risk of $240).
Worked example, ES: risk $250, stop 4 points. Loss per contract = 4 × $50 = $200. Size = 1.25, so 1 contract (a real risk of $200).
How do you size a crypto trade?
Crypto has no lots, so the calculator gives a position value. Position value = risk in dollars ÷ stop distance as a fraction of the entry price. You enter the entry price and the stop price, and it also gives the number of coins.
Worked example, $100K account: risk 0.5% = $500. Entry and stop are 2% apart. Position value = $500 ÷ 0.02 = $25,000. A tighter 1% stop would allow $50,000 for the same risk, and a wider 4% stop only $12,500.
What risk per trade should you use on a prop firm account?
There is no single answer, but the daily loss limit gives you a hard way to think about it. Divide the daily limit by your risk per trade to see how many losers fit in a day:
| Risk per trade | Daily loss limit 5% | Daily loss limit 3% | Daily loss limit 2% |
|---|---|---|---|
| 0.25% | 20 losses | 12 losses | 8 losses |
| 0.5% | 10 losses | 6 losses | 4 losses |
| 1% | 5 losses | 3 losses | 2 losses |
| 2% | 2 losses (the third breaches) | 1 loss (the second breaches) | 1 loss reaches the limit |
The table shows the number of full-size losses that reach the limit exactly, so it counts the last one as the one that uses the whole limit. Leave a margin; do not plan to lose all of it.
Daily loss limits differ by firm. On 29 October 2026 the compare tool showed 2% at Funding Pips (1 Step Flex), 3% at FundedNext (Stellar 1-Step) and 5% at The5ers (High Stakes) for the $100K account; check the firm's own page before you rely on a figure, because firms change rules and our rule changes tracker lists them.
My experience: I set the risk first from the daily limit, then the size from the stop. If a stop is so wide that even the smallest size risks too much, the calculator says so, and the right answer is to skip that trade, not to widen the risk.
How do the stop distance and size trade off?
The risk in dollars stays fixed, so a wider stop means a smaller size and a tighter stop means a bigger one. On the $100K EUR/USD example above, a 10-pip stop at 0.5% risk allows 5 lots, a 20-pip stop allows 2.5 lots and a 40-pip stop allows 1.25 lots. The size follows the stop; the stop does not follow the size.
Common sizing mistakes on prop firm accounts
- Sizing from a lot you like, then picking the stop. Pick the stop from the chart, then let the risk set the size.
- Forgetting that the daily limit counts floating loss too. Check your firm's rules for how it counts open trades.
- Using the same lot size on different pairs. A pip is not worth the same on every pair; enter the pair.
- Rounding up. Round down so the real risk stays at or below the plan.
- Risking the same on every trade after a loss streak. Cut the risk, not the stop.
- Not rechecking after a rule change. If your firm changes its limits, change the numbers in the calculator.
Is the calculator free, and is it financial advice?
It is free and needs no account. It is a calculation tool, not advice: it does not know your strategy, your firm's exact rules or the spread and commission on your platform. Trading carries a high risk of losing money.
Frequently asked questions
A tool that turns your risk per trade and stop loss into a size for your platform: lots for forex and CFDs, contracts for futures, or a position value for crypto. It rounds down so the real risk never exceeds your plan.
Lots = risk in dollars ÷ (stop in pips × pip value per lot). On a $100K account with 0.5% risk ($500) and a 20-pip EUR/USD stop at $10 a pip per lot, that is 2.5 lots.
It depends on your risk and stop, not the account size alone. At 0.5% risk ($250) and a 25-pip EUR/USD stop, loss per lot is $250, so the size is 1 lot. A tighter stop allows more, a wider stop less.
One lot of gold is 100 ounces, so a $1 move is $100 per lot. On a $50K account with 0.5% risk ($250) and a $5 stop, the size is 0.5 lots.
Contracts = risk in dollars ÷ (stop in points × dollar value of one point). ES is $50 a point, NQ $20 and MNQ $2. With $250 risk and a 20-point MNQ stop, that is 6 contracts.
Position value = risk in dollars ÷ the stop distance as a fraction of entry. With $500 risk and a 2% stop, the position value is $25,000.
Many traders use 0.25% to 1%, but the right number depends on your firm's daily loss limit and your strategy. Divide the daily limit by your risk to see how many losses fit in a day.
You enter your firm's daily and maximum loss in percent. The tool shows how many losses in a row you can take before the daily limit at your risk level, and draws the balance falling on a runway chart.
It works for any firm that trades forex and CFDs, futures or crypto. Limits and rules differ by firm, so enter your firm's own daily and maximum loss limits.
Yes. It is free, needs no account, and uses exchange rates from the same day for pairs not quoted in dollars.
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