Position size calculator
Work out how many lots, shares or contracts keep the loss at your stop to a set amount, for forex, gold and silver, stocks and futures.
How it is calculated
Every market uses the same idea. Decide the amount the trade may lose if the stop is hit, work out what one lot, share or contract loses over the stop distance, and divide the first by the second.
Forex, gold and silver
- Pip size is 0.0001 for most pairs and 0.01 for pairs quoted in Japanese yen. For gold (XAUUSD) the calculator uses 0.01, and for silver (XAGUSD) 0.001.
- Contract size is the number of units in one standard lot: 100,000 of the base currency for forex, 100 ounces for gold and 5,000 ounces for silver, the usual specification on MetaTrader-style platforms.
- Rate converts the pip value from the pair’s quote currency, the second currency in its name, into the account currency. It is 1 when the two are the same.
The pip value comes out in the quote currency first. On EURUSD, one pip on one lot is 0.0001 × 100,000 = 10 USD. On USDJPY it is 0.01 × 100,000 = 1,000 JPY, which a USD account converts at the JPY to USD rate.
Stocks
Futures and index CFDs
Shares and contracts are whole numbers and lots move in steps of 0.01, so every size is rounded down. Rounding down keeps the loss at the stop at or below the risk amount; each result shows the risk at the rounded size.
Worked examples
EURUSD, USD account
Balance 10,000 USD, risk 1%, stop 25 pips.
| Step | Working | Result |
|---|---|---|
| Risk amount | 10,000 × 1 ÷ 100 | 100.00 USD |
| Pip value per lot | 0.0001 × 100,000 × 1 | 10.00 USD |
| Lots | 100 ÷ (25 × 10) | 0.40 lots |
| Units | 0.40 × 100,000 | 40,000 |
0.40 lots is 4 mini lots or 40 micro lots.
USDJPY, USD account, with a conversion
Balance 10,000 USD, risk 1%, stop 32 pips. At a USDJPY price of 160.00, one yen is worth 1 ÷ 160 = 0.00625 USD, so that is the rate.
| Step | Working | Result |
|---|---|---|
| Risk amount | 10,000 × 1 ÷ 100 | 100.00 USD |
| Pip value per lot | 0.01 × 100,000 × 0.00625 | 6.25 USD |
| Lots | 100 ÷ (32 × 6.25) | 0.50 lots |
Enter the rate with enough decimals. A rate rounded up, even slightly, makes each pip worth a little more, and because the size is rounded down it can fall to the next 0.01 lot below.
Gold, USD account
Balance 10,000 USD, risk 1%, stop 5.00 below entry, which is 500 pips at a pip size of 0.01.
| Step | Working | Result |
|---|---|---|
| Pip value per lot | 0.01 × 100 × 1 | 1.00 USD |
| Lots | 100 ÷ (500 × 1.00) | 0.20 lots |
| Quantity | 0.20 × 100 | 20 oz |
A stock and a futures contract
| Trade | Working | Result |
|---|---|---|
| Stock: balance 25,000, risk 0.5%, entry 48.20, stop 46.95 | 125 ÷ 1.25 per share | 100 shares |
| MES: risk 500, stop 8 points at 5 per point | 500 ÷ 40 per contract | 12 contracts |
| ES: risk 500, stop 8 points at 50 per point | 500 ÷ 400 per contract | 1 contract |
The stock position is worth 4,820.00. The 12 MES contracts risk 480.00 at the stop and the single ES contract risks 400.00, both under the 500 set.
Pitfalls and assumptions
- Pips, not points. Most platforms quote forex to five decimals, or three on yen pairs. The last digit is a point, sometimes called a pipette, and 10 points make one pip. A 25-pip stop entered as 250 sizes the trade ten times too small.
- Yen pairs. One pip is 0.01, not 0.0001. The calculator switches automatically for any pair quoted in JPY.
- Contract sizes differ between brokers. Gold at 100 ounces per lot is common but not universal, and index CFDs vary widely. Check the symbol specification in your platform before trading a size.
- Costs are not included. Spread, commission and swap come on top, and a stop can fill beyond its price when the market gaps or moves quickly. The result is the loss at the stop price, not a maximum.
- The conversion rate moves. When the quote currency differs from the account currency, the result is exact only at the rate entered.
- Margin is a separate question. A size that fits the risk amount can still need more margin than the account has free, especially with a tight stop.
Frequently asked questions
How do you calculate position size in forex?
Multiply the balance by the risk percentage to get the risk amount. Work out the value of one pip on one lot in the account currency: pip size × 100,000 × conversion rate. Then divide the risk amount by the stop in pips times that pip value. With 10,000 USD, 1% risk and a 25-pip stop on EURUSD: 100 ÷ (25 × 10) = 0.40 lots.
How many units are in a standard, mini and micro lot?
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). So 0.40 lots is 4 mini lots, 40 micro lots or 40,000 units.
What goes in the “1 JPY = ? USD” field?
The value of one unit of the pair’s quote currency in your account currency. Find the quote currency against your account currency on your platform, such as JPYUSD, and enter its price. If your platform only lists the pair the other way round, such as USDJPY, enter 1 divided by its price. The field is fixed at 1 when the quote currency is the account currency.
What is a pip on gold?
This calculator uses 0.01 on XAUUSD, so a 5.00 move is 500 pips, with 100 ounces per lot. Some brokers and traders call 0.10 a pip on gold instead. That is why the gold tab asks for the stop as a price distance: the lot size comes out the same whichever pip convention you use.
Does the position size include spread and commission?
No. It sizes the trade so that the move from entry to stop costs the risk amount. Spread, commission, swap and slippage come on top, so the actual loss at the stop is usually a little larger.
Why is the result rounded down?
Platforms accept sizes in steps: 0.01 lots, whole shares, whole contracts. Rounding up would put more than the risk amount at stake, so each size is rounded down and the risk at the rounded size is shown with it.
Related calculators
- Pip value calculatorWhat one pip is worth in your account currency for any forex pair, gold or silver, at any lot size.
- Risk reward ratio calculatorThe reward-to-risk ratio from entry, stop and target, and the win rate that ratio needs to break even.
- Prop firm drawdown calculatorRoom left today and overall under daily loss and maximum loss rules, static or trailing, and which rule binds first.
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