What is a forex lot size calculator?
A lot size calculator turns a risk decision into an order size. You decide how much of the account you are willing to lose if the stop loss is hit, and the calculator works out how many lots that stop distance allows on the instrument you trade.
The Fips lot size calculator does the math in your account currency, converts cross rates automatically and shows pip value, margin and risk-reward next to the result, so you can copy the volume straight into MetaTrader, cTrader or your broker's platform.
How to use the lot size calculator
Step by step
- Enter your account balance and choose the account currency.
- Set the risk per trade, as a percentage of the balance or as a fixed amount.
- Pick the instrument: a forex pair, gold, silver or a crypto pair.
- Enter the stop loss, either as a distance in pips or as a price level.
- Optionally add a take profit to see the risk-reward ratio.
Position sizing formula
Lot size = (Account balance × Risk %) ÷ (Stop loss in pips × Pip value per lot)Every value in the formula has to be in the same currency. The risk amount is fixed first; the lot size is whatever keeps the loss at the stop equal to that amount.
How lot size is calculated, step by step
Every position size calculation follows the same three steps, whatever the instrument:
- Risk amount = account balance × risk percentage.
- Loss per lot = stop loss distance × value of one pip (or point) on 1.00 lot.
- Lot size = risk amount ÷ loss per lot, rounded down to your broker's lot step (usually 0.01).
The only thing that changes between instruments is the value of one pip per lot, and that comes from the contract size. The examples below use the same contract specifications as the calculator above.
Worked examples
EURUSD (forex)
1.00 lot = 100,000 EUR · 1 pip = 0.0001 · $10 per pip per lot
- Account: $10,000, risk 1% → risk amount $100
- Stop loss: 25 pips
- Loss per lot: 25 × $10 = $250
- Lot size: $100 ÷ $250 = 0.40 lots
USDJPY (yen-quoted pair)
1.00 lot = 100,000 USD · 1 pip = 0.01 · ¥1,000 per pip per lot
- Account: $10,000, risk 1% → risk amount $100 (¥15,000 at 150.00)
- Stop loss: 30 pips
- Loss per lot: 30 × ¥1,000 = ¥30,000
- Lot size: ¥15,000 ÷ ¥30,000 = 0.50 lots
XAUUSD (gold)
1.00 lot = 100 oz · 1 pip = $0.10 · $10 per pip per lot ($100 per $1 move)
- Account: $5,000, risk 1% → risk amount $50
- Stop loss: $10.00 below entry (100 pips of $0.10)
- Loss per lot: 100 × $10 = $1,000
- Lot size: $50 ÷ $1,000 = 0.05 lots
US30 (Dow Jones index CFD)
1.00 lot = $1 per index point (the most common retail contract)
- Account: $20,000, risk 0.5% → risk amount $100
- Stop loss: 80 points
- Loss per lot: 80 × $1 = $80
- Lot size: $100 ÷ $80 = 1.25 lots
Some platforms call $0.01 a pip on gold. What matters is the dollar distance to the stop: a $10.00 stop on 1.00 lot of gold always risks $1,000.
Index CFD contract sizes differ between brokers; some use $10 or $0.10 per point for 1.00 lot. Check the contract specification in your platform before sizing an index trade and scale the result if it differs.
Standard, mini and micro lots
Trading volume is entered in lots. The decimal you type into the order ticket maps to these sizes:
| Lot type | Volume | Forex units | EURUSD per pip | XAUUSD | US30 per point |
|---|---|---|---|---|---|
| Standard | 1.00 | 100,000 | $10.00 | 100 oz | $1.00 |
| Mini | 0.10 | 10,000 | $1.00 | 10 oz | $0.10 |
| Micro | 0.01 | 1,000 | $0.10 | 1 oz | $0.01 |
0.01 is the smallest order most brokers accept on standard accounts. Nano lots (0.001) only exist on some cent accounts.
Pip value per lot for major instruments
Pip value of 1.00 lot for a USD account. For pairs quoted in USD it is fixed; for everything else it moves with the exchange rate, which is why the calculator converts it at the current rate.
| Instrument | Pip size | Pip value (quote currency) | In USD |
|---|---|---|---|
| EURUSD, GBPUSD, AUDUSD, NZDUSD | 0.0001 | $10 | $10.00 |
| USDJPY | 0.01 | ¥1,000 | ≈ $6.67 at 150.00 |
| EURJPY, GBPJPY | 0.01 | ¥1,000 | ≈ $6.67 at USDJPY 150.00 |
| USDCHF | 0.0001 | CHF 10 | ≈ $11.11 at 0.9000 |
| USDCAD | 0.0001 | CAD 10 | ≈ $7.41 at 1.3500 |
| XAUUSD (gold) | 0.10 | $10 | $10.00 |
| US30 (per point) | 1.0 | $1 | $1.00 |
The rates in the last column only illustrate the conversion; they are not live quotes.
Common lot size mistakes
Using the same lot size on every trade
Trading 0.10 lots on every setup means a 15-pip stop and a 60-pip stop carry four times different risk. Size from the stop, not from habit.
Treating gold and indices like forex
A gold or US30 lot is not 100,000 units. Applying forex pip values to them produces a size that is off by orders of magnitude.
Skipping the currency conversion
On USDJPY or EURGBP a pip is not worth $10. If your account is in USD, EUR or TRY, the loss has to be converted into that currency before you divide.
Ignoring spread and commission
Spread and commission come out of the same risk budget. A $7 round-turn commission per lot adds $2.80 to the loss on a 0.40-lot trade.
Rounding up
0.057 lots is 0.05, not 0.06. Rounding up to the next lot step quietly raises the risk above the percentage you chose.
Confusing leverage with risk
Leverage only changes the margin a trade ties up. The loss at the stop depends on lot size and stop distance, not on whether the account runs 1:30 or 1:500.
