Forex Position Size Calculator

Calculate the correct lot size for any forex trade based on your account balance, risk percentage, and stop-loss distance. Works for all pairs including JPY, non-USD accounts.

Exchange Rate

USD is both the quote currency and your account currency — enter 1.0.

Formula

Three-step formula

Step 1 — Risk Amount Risk Amount = Balance × (Risk% ÷ 100)
Step 2 — Pip Value Pip Value/Lot = Pip Size × 100,000 × Quote→Account Rate
Step 3 — Position Lots = Risk Amount ÷ (Stop Pips × Pip Value/Lot)

Pip Size = 0.0001 for most pairs · 0.01 for JPY quote pairs (e.g. USD/JPY, GBP/JPY)

Worked Example

Given

$10,000 account · 1% risk · 20-pip stop-loss · EUR/USD · USD account

Risk Amount
$10,000 × 1% = $100
Pip Size (EUR/USD)
0.0001
Quote→Account Rate (USD/USD)
1.0
Pip Value / Lot
0.0001 × 100,000 × 1.0 = $10.00
Position Size
$100 ÷ (20 × $10) = 0.5 lots (50,000 units)

Frequently Asked Questions

What is position sizing in forex trading?
Position sizing determines how many lots (or units) to trade so that if your stop-loss is hit, your loss equals exactly the dollar amount you are willing to risk. Correct position sizing keeps your risk consistent regardless of stop-loss distance or instrument — a wider stop means a smaller position, not more risk.
Why does my position size change for JPY pairs?
For pairs where JPY is the quote currency (e.g. USD/JPY, GBP/JPY), each pip is worth 0.01 price units instead of 0.0001. This changes the pip value per lot significantly. The calculator detects JPY pairs automatically and uses the correct pip size, so you always get the right answer.
What should I enter for the Quote → Account Rate?
This rate converts the quote currency of your pair into your account currency. For EUR/USD with a USD account, the quote currency IS USD, so enter 1.0. For GBP/JPY with a USD account, the quote currency is JPY — enter 1 divided by the current USD/JPY rate (e.g. if USD/JPY = 150, enter 1÷150 = 0.00667). The dynamic hint below the field updates as you change your pair and account currency.
What is the maximum safe risk percentage per trade?
Professional risk management guidelines recommend risking no more than 1–2% of your account per trade. The calculator warns you when risk exceeds 5%. Higher risk percentages can lead to rapid drawdown: risking 10% per trade, a run of 10 losing trades reduces a $10,000 account to under $3,500.