Forex lot size calculator.
Also called a position size calculator. Pick your market, enter your balance, how much you'll risk and your stop in pips. It works out the lot size so a losing trade costs only what you planned.
Approximate: currency conversion uses static rates (Oct 2026), not a live feed, so results can be a little out. Index contract sizes vary (often 1, 10 or 20 per point per lot), so set yours. Always check with your broker before you trade.
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How to work out your forex position size
- Decide your risk. Many traders use 1% of the account. On £5,000 that's £50.
- Measure your stop in pips. On most pairs 1 pip = 0.0001; on JPY pairs 1 pip = 0.01.
- Find the pip value. 1.00 standard lot = 100,000 units, so 1 pip is worth 10 units of the quote currency (10 USD on EUR/USD, 1,000 JPY on USD/JPY), converted to your account currency.
- Divide: lot size = money at risk ÷ (stop in pips × pip value per lot).
Example: £5,000 account, 1% risk (£50), GBP/USD, 25-pip stop. 1 pip on 1 lot = $10 ≈ £7.46. £50 ÷ (25 × £7.46) = 0.268, rounded down to 0.26 lots. The calculator always rounds down, so you never risk more than you planned.
Lot sizes: 1.00 = standard (100,000), 0.10 = mini (10,000), 0.01 = micro (1,000).
Questions
What is a forex lot size calculator?
A tool that works out how many lots to trade so that, if your stop loss is hit, you lose only the amount you chose. It's the same thing as a position size calculator.
How do I calculate position size in forex?
Position size = money at risk ÷ (stop loss in pips × pip value per lot). The calculator does this for you and converts to GBP, USD or EUR.
Why are JPY pairs different?
On pairs like USD/JPY and GBP/JPY one pip is 0.01, not 0.0001, and the pip value is in yen, so it has to be converted. The calculator handles this.
Does it work for NAS100 and US30?
Yes. Here 1 pip = 1 index point. Set how much 1.00 lot is worth per point on your platform (often $1, $10 or $20), because brokers differ.
Are the exchange rates live?
No. Conversions use fixed approximate rates, so results can be slightly off. Always check the final size with your broker.
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