Forex Lot Size Calculator

Position sizing is the single biggest factor in whether a losing trade is a minor setback or an account-ending mistake. The lot size calculation itself is simple once you have the right inputs: it converts a risk budget (how much of your account you're willing to lose on one trade) and a stop-loss distance (how far price has to move against you before you're out) into a position size that keeps the loss, if it happens, at exactly the amount you planned for.

How the calculation works

The formula is: Position size = Risk amount / (Stop-loss in pips × pip value per standard lot). Risk amount is either a percentage of your account balance (most traders use 0.5–2% per trade) or a fixed dollar figure. Pip value per standard lot depends on the pair's pip size (0.0001 for most pairs, 0.01 for JPY pairs) and, if your account currency differs from the pair's quote currency, the current exchange rate between the two.

A worked example

A $1,000 account risking 1% ($10) on EUR/USD with a 20-pip stop loss: pip value per standard lot is 0.0001 × 100,000 = $10, so position size = $10 / (20 × $10) = 0.05 lots. Trading a larger size than that on the same setup means risking more than 1% if the stop is hit.

The exchange rate auto-fills from live ECB reference rates for ~25 major and cross pairs (gold and silver too, though metals' pip/contract conventions vary by broker, so double-check those) — edit the field directly any time to override it. Enter a stop either in pips or as entry/stop price levels, and read the result in standard, mini, micro, or nano lots. A handful of crypto pairs are in there too, sized directly in coin units with a live-price button pulling from Binance.

This calculator doesn't place trades or connect to your broker — it only does the math, so you can plug the result straight into your MT4/MT5 order ticket.