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Risk & position sizing

Lot Size Calculator

Convert a position size into standard, mini and micro lots for your broker.

Inputs it asks for
Account balance value
Risk per trade % value
Stop distance, pips value
Pair type choose
Formula shown · assumptions disclosed

What it computes

Convert a position size into standard, mini and micro lots for your broker. The page states the equation, the units it expects and the rounding it applies, so the result can be reproduced by hand.

Where it sits in the chain

A calculator gives you a number. This one feeds the next: account to risk, risk to position size, position size to the trade, and the trade to expectancy, drawdown and risk of ruin.

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Inputs
Result
Risk amount $250
Lot size 0.50 lots
In units 50,000
Mini lots 5.0
Micro lots 50
Ignores spread and commission. The Position Size Calculator subtracts those from the risk budget first.
Save this result to your dashboard. Save

The formula

lots = (account × risk%) ÷ (stop pips × pip value per lot)

Identical to position sizing, expressed in the units an FX broker accepts. A standard lot is 100,000 units; a mini is 10,000; a micro is 1,000.

Worked example

A $25,000 account, 1% risk, 50-pip stop, USD-quoted pair at $10 per pip per lot:

risk = 25,000 × 0.01 = $250
lots = 250 ÷ (50 × 10) = 0.50 lots
= 50,000 units
= 5 mini lots

What it assumes

  • Pip value is $10 per standard lot on USD-quoted pairs. On JPY-quoted pairs it is 1,000 ÷ price.
  • Spread and commission are excluded, so the realised risk is slightly above the figure shown.
  • Your broker may have a minimum increment. Round down to it.

Common questions

What is a lot in forex?

A standard lot is 100,000 units of the base currency. A mini lot is 10,000 and a micro lot is 1,000, so 0.50 lots is 50,000 units or five mini lots.

Why does the pip value differ on JPY pairs?

A pip on a JPY-quoted pair is 0.01 rather than 0.0001, and the value depends on the current rate: 1,000 divided by the price, per standard lot.

What lot size should a beginner use?

The smallest your broker allows, until you have a hundred trades of record. Micro lots at 0.01 put $0.10 per pip at stake, which is enough to learn the mechanics and too little to matter if the strategy is wrong.

What to work out next

A calculator answers one question and raises the next. These are the ones this figure feeds into.

Pip Calculator

What one pip is worth on the pair and size you are trading.

Stop Loss Calculator

Work backwards from accepted risk and a fixed size to the stop distance that fits.

Margin Calculator

Required margin for a position, and the effective leverage it puts on the account.

Lot Size Calculator · rounding shown to the precision displayed

More in risk & position sizing

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Stop Loss Calculator

Work backwards from accepted risk and a fixed size to the stop distance that fits.

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Risk/Reward Calculator

Compare reward with risk, and read off the win rate that ratio needs to break even.

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Position Size Calculator

Turn an account balance, a risk percentage and a stop distance into a size in lots, shares or contracts.

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Risk Calculator

The maximum you should lose on one trade, before anything else about the trade is decided.

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Quantify the trade, then keep the record.