Forex Lot Size Calculator
Position size from the risk you are willing to take: pick the account currency, the balance, the risk as a percentage or an amount, the market and the stop distance — in pips, or straight from your entry and stop prices — and read the lot size (standard, mini, micro), the money at risk and the pip value in your account currency. The lot is rounded down to the nearest 0.01, so the risk you take is never more than the risk you typed. Free, no sign-up.
Position size from the risk you set
Fill the four fields on the left; the result on the right updates as you type. The exchange rates behind the pip value are analysis prices refreshed a few times a day on trading days, not tick by tick — they only affect the conversion of the pip value into your account currency, never the size of your stop.
- Mini lots (0.1)
- 5.0
- Micro lots (0.01)
- 50
- Money at risk
- 100.00 USD
- Stop distance
- 20 pips
- Pip value per lot
- 10.00 USD
Exchange rate for the pip value: analysis price of 8 Sep 2026, 09:18 UTC.
How the lot size calculator works
A lot size calculator turns a decision you can make calmly — how much of the account a single trade may lose — into the number MetaTrader actually asks for: the volume, in lots. Three quantities go in. The risk in money (a percentage of the balance, or a flat amount). The stop distance in pips, which is the only part of the trade you control precisely. And the value of one pip for one standard lot, expressed in your account currency, which depends on the market and on the exchange rate between its quote currency and yours.
The formula is the same for every market:
The pip value per standard lot is pip size multiplied by contract size. For most currency pairs a pip is 0.0001 and a standard lot is 100,000 units, so one pip is worth 10 units of the quote currency (10 USD on EUR/USD, 10 GBP on EUR/GBP). Yen pairs have a pip of 0.01, so one pip is worth 1,000 JPY per lot. Gold is measured in points of 1.00 on a 100-ounce lot, so one point is worth 100 USD per lot. When the quote currency is not your account currency, the calculator converts with the analysis exchange rate: 10 GBP on a USD account becomes about 13 USD at 1.30, and 1,000 JPY becomes about 6.67 USD at 150.
The last step is the rounding. Brokers accept volumes in steps of 0.01, and the calculator rounds down to that step: a raw result of 0.3077 lots becomes 0.30, never 0.31. Rounding up would put more money at risk than you decided, which defeats the purpose of sizing from risk in the first place. The result panel shows the money actually at risk after rounding, so you can see how much of your budget the step left on the table.
Three worked examples
The numbers below are examples with round exchange rates, chosen to show the mechanics; the calculator above uses the current analysis price instead.
EUR/USD on a USD account
Balance $10,000, risk 1% ($100), stop 20 pips. One pip on a standard lot is 10 USD, already your currency. Lots = 100 ÷ (20 × 10) = 0.50. Half a standard lot, or five mini lots, puts exactly $100 at risk if the stop is hit.
USD/JPY on a USD account
Same $100 of risk, stop 30 pips. One pip on a standard lot is 1,000 JPY; at a USD/JPY rate of 150 that is 6.67 USD. Lots = 100 ÷ (30 × 6.67) = 0.4999, rounded down to 0.49. The rounding costs you two dollars of unused risk budget — the price of never exceeding it.
XAU/USD (gold) on a USD account
Gold is the case that catches people out, because its unit is a point of 1.00 in price, not a pip, and a standard lot is 100 ounces. With a 5-point stop and $100 of risk: one point per lot is 100 USD, so lots = 100 ÷ (5 × 100) = 0.20. Typing “50 pips” here, as if gold were a currency pair, would size the position ten times too large.
The mistakes a calculator exists to prevent
- The same lot on every trade. A fixed 0.10 lot with a 15-pip stop risks $15; the same 0.10 lot with a 60-pip stop risks $60. The position size has to follow the stop, not the other way around, or the risk per trade quietly varies fourfold.
- Yen pairs and gold treated like EUR/USD. The pip is 0.01 on yen pairs and the unit is a point on gold. The calculator applies the right unit for the market you pick, and shows it next to the stop distance so you can check.
- Forgetting the account currency. A EUR account trading GBP/USD earns and loses in USD; the pip value has to be converted, and the rate moves. That is why the pip value is recomputed for every market and shown explicitly, and why you can type your broker’s figure if it differs.
- Rounding the lot up. Brokers step volumes in hundredths; going to the next step up can push the risk a few percent above the decision you made. Round down and keep the difference.
- Sizing before placing the stop. The stop is an input here, not an output. Where it belongs — beyond the level that protects the idea, or at a volatility distance — is a separate decision, covered in where to place a stop loss in forex. Size the trade after you have that number, never before.
This is the arithmetic the AI Trade Panel does at every click. Set the risk once as a percentage of equity or balance, pick a signal or the day’s AI plan, and the lot is worked out from the stop of that trade before the confirmation dialog opens — then the order goes to MetaTrader 5 with its stop and target attached. The panel never opens a trade by itself; it makes the order you decided correct. See how the panel sizes an order, or read the longer MT5 trade panel guide first.
Related reading
- Where to place a stop loss in forex — structure, ATR, and the rule the nightly plan applies before any lot is computed.
- Forex trade management after entry — breakeven, trailing, partial close, and when to leave a sized trade alone.
- Volatility analysis — the ATR of each market in its own unit, the reference for a volatility stop.
- The MT5 trade panel guide — what a trade panel does, what it can’t, and how the free and paid options compare.
