Forex Position Size and Lot Size Calculator
Reviewed by Phillip Ashdown, Senior Forex Analyst · Last reviewed 22 October 2026
Position size (lots) = amount you risk ÷ (stop loss in pips × pip value per lot). Risking 1% of £5,000 (£50) with a 25-pip stop on EUR/USD gives 0.26 lots, with £48.59 actually at risk once rounded down to the nearest 0.01 lots.
Enter your account balance, the percentage you are willing to risk and your stop loss distance. The calculator works out the lot size that keeps your loss within that limit if the stop is hit, using the pip value of the pair in your account currency.
How to Calculate Position Size in Forex
Position size (lots) = (account balance × risk %) ÷ (stop loss in pips × pip value per standard lot)
- Work out your risk amount: account balance multiplied by the percentage you are prepared to lose.
- Find the pip value of one standard lot of your pair in your account currency (see the pip value calculator).
- Multiply that pip value by your stop loss distance in pips. This is what one standard lot would lose if the stop is hit.
- Divide your risk amount by that figure, then round down to the nearest 0.01 lots.
Position Size Worked Examples
EUR/USD, £5,000 account, 1% risk, 25-pip stop
| Risk amount | £5,000 × 1% = £50.00 |
|---|---|
| Pip value per standard lot | $10 ÷ 1.3376 = £7.4761 |
| Loss per lot at the stop | 25 × £7.4761 = £186.90 |
| Exact position size | £50.00 ÷ £186.90 = 0.268 lots |
| Rounded down | 0.26 lots |
| Actual risk | £48.59 |
GBP/JPY, £10,000 account, 1% risk, 40-pip stop
| Risk amount | £10,000 × 1% = £100.00 |
|---|---|
| Pip value per standard lot | ¥1,000 converted to GBP = £4.7605 |
| Loss per lot at the stop | 40 × £4.7605 = £190.42 |
| Exact position size | £100.00 ÷ £190.42 = 0.525 lots |
| Rounded down | 0.52 lots |
| Actual risk | £99.02 |
Yen pairs have a lower pip value per lot than USD-quoted pairs, so the same risk buys a larger position. Conversions use ECB reference rates, 22 October 2026.
Gold (XAU/USD), £5,000 account, 1% risk, entry 2,650, stop 2,640
| Risk amount | £5,000 × 1% = £50.00 |
|---|---|
| Stop distance | $10.00 ÷ $0.10 = 100 pips |
| Pip value per lot (100 oz) | $10 ÷ 1.3376 = £7.4761 |
| Exact position size | £50.00 ÷ (100 × £7.4761) = 0.067 lots |
| Rounded down | 0.06 lots |
| Actual risk | £44.86 |
Each 0.01 lot of gold is a full ounce, so the rounding step is large and the actual risk can fall well short of your limit. Entering prices rather than pips avoids any mismatch over what your platform calls a gold pip.
Spread bet on GBP/USD, £2,000 account, 1% risk, 20-point stop
| Risk amount | £2,000 × 1% = £20.00 |
|---|---|
| Stake per point | £20.00 ÷ 20 points = £1.00 per point |
In a spread bet the stake is already in pounds, so no exchange rate is needed: stake per point = risk amount ÷ stop distance in points.
Spread Betting Position Size Calculator
Switch the calculator to spread bet and it works out your stake in pounds per point instead of a lot size: stake per point = amount you risk ÷ stop distance in points. Because the stake is already in pounds, no exchange rate is involved, whether you are betting on GBP/USD, gold or the US Tech 100. The stake is rounded down to the nearest penny, and the result also shows the equivalent CFD size and the margin needed. See what spread betting is for how stakes and points work.
How Much Margin Do You Need?
The FCA caps leverage for retail clients, which sets the minimum margin a broker can ask for: 3.33% of the position's value (30:1) on major currency pairs, and 5% (20:1) on other pairs, gold and major indices. In the EUR/USD example above, 0.26 lots is 26,000 euros, about £21,780, so the margin is about £726.01. Brokers may ask for more, and margin is not the most you can lose. The calculator shows the margin for every forex result; for gold and indices it needs your entry price.
Why the Calculator Rounds Down
Most brokers let you trade in steps of 0.01 lots (one micro lot). Rounding to the nearest step would sometimes round up and take you over your risk limit. The calculator always rounds down, then shows the actual amount at risk at that size, so the figure you set is a ceiling rather than a target.
What Risk Percentage Should You Use?
Many traders risk between 0.5% and 2% of their account on a single trade. The lower end limits how quickly a run of losses erodes the account: ten consecutive losses at 1% leave you with about 90% of your balance, while ten at 5% leave about 60%. Choose a figure you could sustain through a long losing streak, and remember that most retail accounts trading leveraged products lose money.
Position Sizing With a Small Account
The smallest CFD trade at most brokers is 0.01 lots, worth about £0.075 per pip on EUR/USD. With a small balance and a wide stop, even that can exceed a 1% limit; the calculator flags this when it happens. Your options are a tighter stop, a smaller risk percentage you are comfortable with, or a spread bet, where you set your own stake per point and some providers accept stakes well under £1 per point. Check your provider's minimum stake before you trade.
How to Use This Calculator
- Choose CFD / forex lots or spread bet at the top of the calculator.
- Enter your account balance (and its currency for a CFD) and the percentage you are prepared to risk.
- Select the market: a forex pair, gold or one of the indices.
- Enter your stop loss either as a distance in pips or points, or as entry and stop prices. The price option works for both buys and sells.
- Read the position size in lots and units (or your stake per point for a spread bet), the pip value at that size and the actual amount at risk. The page address updates as you type, so you can bookmark or share a calculation.
Frequently Asked Questions
How do I calculate lot size in forex?
Divide the amount you are willing to risk by your stop loss in pips multiplied by the pip value of one standard lot. The result is your position size in standard lots; round it down to the nearest 0.01.
What does a 0.01 lot mean?
A 0.01 lot is a micro lot: 1,000 units of the base currency. On EUR/USD each pip is worth 10 cents, about £0.075 on a GBP account. A 0.1 lot (mini lot) is 10,000 units and a 0.2 lot is 20,000 units, worth about £1.50 per pip on EUR/USD. Most UK brokers let you trade from 0.01 lots.
How do I calculate position size for gold?
Work out your risk amount, then divide it by the stop distance multiplied by the value of a move on one lot. With 100 ounces per lot, every $1 move in the gold price is $100 per lot. Enter your entry and stop prices in the calculator and it does this for you, without needing to agree what a gold pip is.
How much margin do I need for a trade?
Under FCA rules, retail clients put up at least 3.33% of the position's value on major currency pairs (30:1 leverage) and 5% on other pairs, gold and major indices (20:1). The calculator shows the margin for its result. Brokers can ask for more, and you can lose more than the margin if the market moves against you.
What is a good risk percentage per trade?
Many traders risk 0.5% to 2% of their balance per trade, with beginners often starting at 1% or less. Risking more than 3% per trade makes deep drawdowns much more likely.
What is a standard lot in forex?
A standard lot is 100,000 units of the base currency. A mini lot is 10,000 units (0.1 lots) and a micro lot is 1,000 units (0.01 lots). Most UK brokers let you trade from 0.01 lots.
How do I calculate position size for a spread bet?
Divide your risk amount by your stop distance in points. Risking £30 with a 15-point stop gives a stake of £2 per point. No currency conversion is needed because spread bets are staked in pounds.
Can I enter my stop as a price instead of pips?
Yes. Switch the stop loss to entry and stop prices and the calculator works out the distance in pips or points for you. This is the safest option for gold, where platforms disagree on what counts as a pip.
Does it work for gold and indices?
Yes, for gold (XAU/USD), the UK 100, US 500, US 30, US Tech 100 and Germany 40. Gold assumes 100 ounces per lot; index contracts assume one unit of currency per point. Check your broker's contract size, as some use larger contracts.
Does this calculator work for GBP accounts?
Yes. Select GBP as the account currency and the risk amount, pip value and actual risk are all shown in pounds, converted at the reference rates shown under the result.