Short answer
This lot size calculator uses one formula: lot size = the amount you're prepared to lose ÷ (stop loss in pips × pip value per lot). On pairs ending in USD, one standard lot is worth USD 10 per pip, so risking USD 10 with a 20-pip stop gives 0.05 lots. The calculator rounds down to the nearest 0.01 lot so the result never goes over your chosen risk.
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The lot size calculator formula
The lot size calculator, also called a position size calculator, works in three steps:
- Amount at risk = balance × risk % ÷ 100
- Loss per lot = stop loss in pips × pip value for one standard lot
- Lot size = amount at risk ÷ loss per lot, rounded down to 0.01
The pip value for one standard lot (100,000 units) depends on the pair:
| Pair type | Examples | Pip value per standard lot |
|---|---|---|
| USD is the second currency | EURUSD, GBPUSD, AUDUSD, NZDUSD | USD 10, fixed |
| USD is the first currency | USDCHF, USDCAD | 10 ÷ current price |
| USD first, yen pair | USDJPY | 1,000 ÷ current price |
For USDJPY, USDCHF and USDCAD the calculator asks for the current price, because the dollar value of a pip changes as the price moves. Copy the price from your platform. If pips are new to you, read what is a pip and what is a lot first.
Worked examples
EURUSD. Balance USD 500, risk 1%, stop 25 pips.
- Amount at risk: 500 × 1% = USD 5
- Loss per lot: 25 × USD 10 = USD 250
- Lot size: 5 ÷ 250 = 0.02 lots
USDJPY. Balance USD 1,000, risk 1%, stop 30 pips, price 150.00 (an example price only).
- Amount at risk: USD 10
- Pip value per lot: 1,000 ÷ 150 = USD 6.67
- Loss per lot: 30 × 6.67 = USD 200
- Lot size: 10 ÷ 200 = 0.05 lots
The examples use 1% because it keeps the arithmetic simple. How much you put at risk on a trade is your decision.
How to read the result
- Position size is the largest size, in standard lots, that keeps your loss at the stop within the amount you chose. It goes in the volume field of your order.
- Amount at risk is what you lose if the stop is hit at exactly that price. Spreads, commission and slippage can make the real loss larger, and prices can gap past a stop over weekends or around news.
- “Below the smallest position” means even 0.01 lots would risk more than you chose. Your options are a tighter stop, a larger risk you’re prepared to accept, or a cent account (see below).
A correctly sized position limits the loss you planned for. It doesn’t make a trade more likely to go your way.
Balance in naira, shillings or rand?
The calculator works in US dollars. If your trading account is in USD, use the balance your platform shows. If you’re planning with naira, shillings or rand, convert to dollars first. The most honest rate to use is the one from your own last deposit: divide the dollars credited by the local currency you paid.
Lot size on a cent account
On a cent account, balances show in US cents (USC) and, at brokers where one cent lot equals 0.01 standard lots, sizes are 100 times smaller:
- Divide your USC balance by 100 to get dollars, and enter that as the balance.
- Multiply the lot result by 100 to get cent lots. A result of 0.03 lots is 3 cent lots.
Small cent balances can give a result below 0.01 standard lots. Work it out by hand: on pairs ending in USD, one cent lot moves 10 US cents per pip. With 1,000 USC, 1% risk (10 USC) and a 20-pip stop: 10 ÷ (20 × 10) = 0.05 cent lots. Check the smallest volume your platform accepts. Our cent account guide explains how these accounts work.
Leverage doesn’t change the result
Leverage changes the margin a position ties up, not the value of each pip, so it plays no part in this calculation. High leverage does let you open positions far larger than this calculator suggests, and that is where big losses come from. Use the margin calculator to see the margin a position needs, and read leverage and margin if the difference isn’t clear.
On Exness accounts
- Standard, Pro, Raw Spread and Zero accounts use standard lots, so enter the result as it is.
- Standard Cent counts in cents: one cent lot equals 0.01 standard lots, and a USD 5 balance shows as 500 USC. Use the cent-account steps above.
- Demo: Exness has demo accounts for every account type except Standard Cent, so you can try a size on a demo first.
For pip values on their own, use the pip value calculator; for XAUUSD, the gold lot size calculator. Practise sizing trades on a demo account before you use real money.
Common questions
Does the calculator include spread and commission?
No. It sizes the position from your stop loss only. Spreads, commission on commission-based accounts, and slippage can make the actual loss larger than the amount shown.
Why does it ask for a price on USDJPY, USDCHF and USDCAD?
On those pairs USD is the first currency, so the dollar value of a pip changes as the price moves. On pairs ending in USD, a pip is fixed at USD 10 per standard lot.
Does leverage change the lot size?
No. Leverage changes how much margin the position ties up, not how much each pip is worth, so it doesn't enter this calculation. Check the margin separately with the margin calculator.
How do I calculate lot size on a cent account?
Enter your balance in dollars (your USC balance divided by 100), then multiply the result by 100 to get cent lots, where one cent lot equals 0.01 standard lots. A result of 0.03 lots is 3 cent lots.
Can I use it for gold?
Use the gold lot size calculator instead. One standard lot of gold is usually 100 ounces, and a gold stop is easier to measure in dollars than in pips.