# What lot size should I trade?

Works out the forex lot size (position size) that risks a chosen percent of your account if the stop loss is hit, in standard, mini and micro lots and units, from rates you type.

- Page: https://www.acalculator.org/finance/lot-size-calculator
- JSON spec: https://www.acalculator.org/finance/lot-size-calculator.json
- Version: ffe678c8a98c

## Default answer

Example with the default inputs (Account balance 10,000, Risk per trade 1%, Stop loss (pips) 50, Pip size 0.0001 (most pairs), Your account currency is The quote currency (EUR/USD, USD account)): Risking 100 with a 50-pip stop, trade 0.2 standard lots (20,000 units).

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| balance | Account balance | The money in your trading account, in its own currency. |
| risk | Risk per trade | The share of the balance you accept to lose if the stop loss is hit. |
| stop | Stop loss (pips) | How far the stop loss is from the entry price, in pips. |
| pip | Pip size | One pip in the pair’s price: 0.0001 for most pairs, 0.01 for pairs quoted in Japanese yen. |
| acct | Your account currency is | The pair’s quote (second) currency, its base (first) currency, or neither; it sets how a pip converts to your money. |
| price | Pair price | The pair’s price: how much quote currency one unit of the base currency buys, such as 150 for USD/JPY. |
| conv | Quote currency in account currency | What one unit of the quote currency is worth in your account currency, such as 1.25 USD per GBP. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| lots | Standard lots | The position size in standard lots of 100,000 units of the base currency. |
| units | Units | The position size in units of the base currency. |
| mini | Mini lots | The size in mini lots of 10,000 units. |
| micro | Micro lots | The size in micro lots of 1,000 units. |
| riskAmount | Money at risk | Balance × risk per trade: what you lose if the stop loss is hit. |
| pipValue | Pip value per standard lot | What one pip is worth in your account currency for one standard lot. |
| roundedLots | Lots rounded down to 0.01 | The size most platforms accept: the standard lots rounded down to the nearest 0.01. |
| roundedRisk | Money at risk at the rounded size | Rounded lots × stop loss × pip value per lot. |

## Method

risk = balance × risk %; pip value per lot = 100,000 × pip size × (1, 1 ÷ price, or the quote-currency rate); lots = risk ÷ (stop pips × pip value per lot).

## Assumptions

- A standard lot is 100,000 units of the base currency; a mini lot 10,000; a micro lot 1,000.
- The pair price and the conversion rate are typed by you; the page fetches no quotes.
- Spread, commission, swap and slippage are not counted; a gap past the stop loses more.
- Arithmetic is exact on the typed decimals; the rounded size is cut down, never up, to 0.01 lot.

## Worked examples

1. balance = 10,000, risk = 1%, stop = 50, pip = 0.0001, acct = quote gives riskAmount = 100, pipValue = 10, lots = 0.2, units = 20,000, mini = 2, micro = 20, roundedLots = 0.2. Source: Commodity Futures Trading Commission, CFTC Glossary ("Pip": the smallest price unit of a commodity or currency). https://www.cftc.gov/LearnandProtect/AdvisoriesAndArticles/CFTCGlossary/index.htm.
2. balance = 5,000, risk = 2%, stop = 30, pip = 0.01, acct = base, price = 150 gives riskAmount = 100, pipValue = 6.666667, lots = 0.5, units = 50,000. Source: Commodity Futures Trading Commission, CFTC Glossary ("Pip": the smallest price unit of a commodity or currency). https://www.cftc.gov/LearnandProtect/AdvisoriesAndArticles/CFTCGlossary/index.htm.
3. balance = 20,000, risk = 1.5%, stop = 40, pip = 0.0001, acct = other, conv = 1.25 gives riskAmount = 300, pipValue = 12.5, lots = 0.6. Source: Commodity Futures Trading Commission, CFTC Glossary ("Pip": the smallest price unit of a commodity or currency). https://www.cftc.gov/LearnandProtect/AdvisoriesAndArticles/CFTCGlossary/index.htm.
4. balance = 2,500, risk = 1%, stop = 35, pip = 0.0001, acct = quote gives lots = 0.071429, roundedLots = 0.07, roundedRisk = 24.5. Source: Commodity Futures Trading Commission, CFTC Glossary ("Pip": the smallest price unit of a commodity or currency). https://www.cftc.gov/LearnandProtect/AdvisoriesAndArticles/CFTCGlossary/index.htm.

## FAQ

### How do I calculate lot size in forex?

Work out the money at risk (balance × risk %), then divide it by the stop loss in pips times the pip value of one standard lot. With $10,000, 1% risk and a 50-pip stop on EUR/USD: $100 ÷ (50 × $10) = 0.2 lots, or 20,000 units.

### What is a pip worth?

For one standard lot (100,000 units), a pip is worth 100,000 × the pip size in the quote currency. On EUR/USD that is 100,000 × 0.0001 = $10. On USD/JPY at 150 it is 100,000 × 0.01 ÷ 150 = $6.67 for a USD account.

### What if my account currency is in neither side of the pair?

Convert the pip value from the quote currency to your account currency. For EUR/GBP with a USD account and GBP worth $1.25, one pip on a standard lot is £10 × 1.25 = $12.50.

### What are standard, mini and micro lots?

A standard lot is 100,000 units of the base currency, a mini lot 10,000, and a micro lot 1,000. 0.2 standard lots is 2 mini lots or 20 micro lots.

### Why round the lot size down?

Most platforms accept sizes in steps of 0.01 lot. Rounding down keeps the loss at the stop at or below your risk limit; 0.0714 lots becomes 0.07 and risks $24.50 instead of $25.

### Does this page use live exchange rates?

No. You type the pair price or the conversion rate, so the answer matches the rate you trade at. The page sends nothing and fetches no quotes.

## Sources

- Commodity Futures Trading Commission, CFTC Glossary ("Pip": the smallest price unit of a commodity or currency). https://www.cftc.gov/LearnandProtect/AdvisoriesAndArticles/CFTCGlossary/index.htm (retrieved 2026-10-02)