Forex Lot Size Calculator

Updated 31 October 2026 · Written by Broker Atlas Guides Desk · Data checked by Broker Atlas Data Desk

Short answer

If you know the cash amount you're willing to lose on a trade, lots = cash at risk ÷ (stop in pips × pip value per lot). Risking $50 with a 25-pip stop on EUR/USD ($10 per pip per lot) gives 0.20 lots. To use this calculator with a cash figure, enter that amount as the balance and 100 as the risk %. Round down to your broker's lot step.

When to use this calculator

Use it when you think in money: “I’m prepared to lose $50 on this trade” or “my daily loss limit is $100 and I’ll take two trades”. It turns that figure and the distance to your stop into a lot size you can type into MT4/MT5. If you prefer to risk a fixed share of your account, the position size calculator covers the percent-risk method.

How to use it

Balance (USD): for a cash limit, enter the amount you’re willing to lose, e.g. 50.
Risk (%): enter 100, so the whole figure above is the risk. (Enter your real balance and a percentage instead and it works as a percent-risk calculator.)
Stop loss (pips): the distance from your entry to your stop. In MT4/MT5, drag the crosshair from entry to stop to read the pips, or subtract the prices: on EUR/USD, 1.0850 to 1.0825 is 25 pips.
Pip value per lot (USD): what one pip is worth on one standard lot in your account currency. The pip value calculator works it out, or use the table below.

Instrument	Pip	Pip value per lot (USD account)
EUR/USD, GBP/USD	0.0001	$10
USD/JPY	0.01	¥1,000 ÷ rate: $6.67 at 150.00
XAU/USD (100 oz)	0.1 (this site’s convention)	$10

Gold pips aren’t standardised: some brokers and platforms count $0.01 as a pip. Check the convention before you enter a stop for gold (gold trading guide).

The formula

Lots = cash at risk ÷ (stop in pips × pip value per lot)

The line under the result repeats the cash at risk, so you can check you entered it as intended.

Worked examples

Example 1: EUR/USD. You’ll risk $50 with a 25-pip stop. Balance 50, Risk 100, Stop 25, Pip value 10. 50 ÷ (25 × 10) = 0.20 lots. If the stop is hit you lose 25 × $10 × 0.20 = $50.

Example 2: USD/JPY. You’ll risk $100, stop 40 pips, rate 150.00, so pip value per lot is 1,000 ÷ 150 ≈ 6.67. Balance 100, Risk 100, Stop 40, Pip value 6.67. 100 ÷ (40 × 6.67) = 0.3748…, shown as 0.37 lots. At 0.37 lots the loss at the stop is about $98.70, just under your limit.

The calculator rounds to two decimals in the usual way, so a result like 0.375 would display as 0.38. If that happens, type 0.37 into MT4/MT5 so you stay at or under your limit.

From lots to units

Lots	Units of base currency	Common name
1.00	100,000	standard lot
0.10	10,000	mini lot
0.01	1,000	micro lot

On a cent account, balances are shown in cents and contract sizes often differ, so read the account’s symbol specification before applying this table. See account types and the cent account comparison.

What the result means, and its limits

The result is the size at which hitting your stop costs your chosen amount, with three caveats:

Spread and commission add to the loss. On an ECN account, add the round-trip commission to your risk.
Slippage. Stops become market orders when triggered, so a fast market or a weekend gap can fill you beyond the stop. See trading high-impact news.
Margin. A small stop can produce a large lot size. Check the margin with the margin calculator and keep enough free margin to avoid a stop-out.

For a fuller approach to sizing and daily limits, read risk management with high leverage and starting forex with $100.

Frequently asked questions

How do I enter a fixed dollar risk instead of a percentage?

Type the dollar amount into Balance and set Risk to 100. The calculator multiplies the two, so $50 × 100% = $50 at risk.

What pip value per lot should I use?

$10 for EUR/USD, GBP/USD and other pairs quoted in US dollars. For USD/JPY it's 1,000 ÷ the rate, about $6.67 at 150.00. For gold this site counts $0.10 as one pip, so it's $10 per lot.

Should I round the result up or down?

Down. MT4/MT5 accept lots in steps (usually 0.01), and rounding up puts slightly more than your limit at risk.

Is this the same as the position size calculator?

The maths is the same. This page starts from a cash loss limit; the position size calculator starts from a percentage of your balance and explains the percent-risk method.