← Position size calculator

UK100 (FTSE 100) lot size calculator

Work out how many lots to trade on UK100 (FTSE 100) so hitting your stop loss costs exactly the amount you chose to risk.

Exchange rates as of 2026-09-30 18:59 UTC, refreshed hourly.

How the UK100 (FTSE 100) position size is calculated

Your risk is the distance between entry and stop loss, multiplied by the contract size. At most brokers one lot of UK100 (FTSE 100) is worth 1 GBP per point, but some use 0.1, 10 or more.

Lots = (balance × risk %) ÷ (|entry − stop| × contract size)

Why does my lot size look wrong?

• Contract size. This is the usual cause. 1 GBP per point per lot is common, but brokers and prop firms set their own. In MetaTrader, right-click the symbol in Market Watch and open Specification to see yours, then enter it above.
• Account currency. UK100 (FTSE 100) is priced in GBP. Pick your account’s currency so the risk is converted correctly.
• Rounding. Results round down to 0.01 lots so you never risk more than you set. Check your broker’s minimum lot step.

Sizing across several accounts?

The Forexizer Calculator app saves each account’s balance, currency, risk and contract sizes, then sizes one trade for every account at once. No retyping, no looking up specs.

Download the app