Lot Size Calculator

How the calculation works

Everything is computed in your browser from the numbers you enter. There is no server, no login and no data sent anywhere.

1. Risk amount = account balance × risk percentage. With a 10,000 USD account at 1%, your risk is 100 USD.
2. Pip value per lot = pip size × contract size, converted into your account currency. On EURUSD that is 0.0001 × 100,000 = 10 USD per pip for one standard lot.
3. Stop loss in money = stop loss in pips × pip value per lot. A 20 pip stop on EURUSD costs 200 USD per standard lot.
4. Lot size = risk amount ÷ stop loss in money. 100 USD ÷ 200 USD = 0.50 lots.
5. Position size = lot size × contract size. 0.50 × 100,000 = 50,000 units.
6. Margin required = position value ÷ leverage. 50,000 units at 1.1000 is 55,000 USD of exposure, so at 1:100 you need 550 USD of margin.
7. Risk / reward = distance to your target ÷ distance to your stop, both measured as price moves.

Rounding: lot size is shown to two decimals. Most brokers accept 0.01 lots (micro), some accept 0.001 — round down if your broker requires it, and never round up.

Pips and points — the part most calculators get wrong

A pip is not a fixed number of decimals across all instruments. It follows the quoting convention:

• On 4-decimal pairs such as EURUSD, 1 pip = 0.0001 and 1 point = 0.00001.
• On JPY-quoted pairs such as USDJPY, 1 pip = 0.01 — the second decimal, not the fourth.
• On metals at 2-decimal quotes, 1 pip = 0.01 of price.
• 1 pip is always 10 points. Brokers that quote 5 decimals usually mean points when they say "pip" on the 5th digit.

This page shows the pip definition for the instrument you picked, directly under the stop loss field, and converts your stop into an actual price move so you can check it against your chart.

Supported instruments

Forex majors and crosses (28 pairs) plus gold (XAUUSD) and silver (XAGUSD). Contract sizes follow the standard industry convention:

• Forex: 1 standard lot = 100,000 units of the base currency.
• Gold: 1 standard lot = 100 troy ounces.
• Silver: 1 standard lot = 5,000 troy ounces.

Index CFDs (US30, NAS100, SPX500 and similar) are not included on purpose. Their contract size and point value differ from broker to broker, so any number printed here would be a guess. Check your broker's contract specification instead.

Where the prices come from

You enter them. This page has no live market feed — it does not fetch prices, and it will never show a price it did not get from you. Open your broker's platform, copy the current bid/ask for the pair you are trading, and paste it into the entry price field.

The same applies to currency conversion. If your account currency matches the quote currency, or matches the base currency, the rate is derived automatically. If neither matches — for example a USD account trading EURGBP — the conversion rate field appears and you fill it in yourself. Leaving it at 1 will give you an estimate, not a usable number.

Common questions

Is this the same as a position size calculator?

Yes. A position size calculator and a lot size calculator answer the same question: how big should this trade be. Lot size is the forex-specific way of expressing position size, which is why both names are used for this tool.

Does it work as a forex lot size calculator for any pair?

For the 28 pairs listed, yes. Pick the pair, enter your stop in pips and the pip value is calculated from that pair's own quoting convention, including JPY pairs where a pip sits on the second decimal.

How is this different from a forex position size calculator that asks for a stop price?

Some tools ask you to type the stop loss price and work backwards. This one asks for the distance in pips, which is how most traders plan a trade from a chart. Either method gives the same answer as long as the pip definition matches — that is exactly why the pip/point conversion is printed on this page.

Why is the lot size sometimes below 0.01?

Because your stop is wide relative to your risk. A 200 pip stop on a small account risks too much per lot, so the correct position is smaller than the minimum your broker allows. Either widen your risk percentage, tighten the stop, or skip the trade — do not round the lot size up.

Does leverage change how much I risk?

No. Leverage only changes the margin required. Your risk is set by account size, risk percentage and stop distance. This is why the risk amount and the margin required are shown as two separate numbers.

Can I use it on my phone?

Yes. The layout collapses to a single column on narrow screens and every input is a native number field, so the numeric keypad comes up on mobile.