Forex Lot Size Calculator
How many lots to trade so a stop-loss costs a set share of your account, with pip values for standard, mini and micro lots.
With a $10,000 account risking 1% ($100) and a 25-pip stop on EUR/USD, trade 0.40 standard lots (40,000 euros): each pip is then worth $4. One standard lot of a USD-quoted pair is worth $10 a pip.
The words on this page, explained simply
New to this? Here is what each term means, in plain English.
- Pip
- The standard price step in forex: 0.0001 for most pairs, 0.01 for pairs quoted in yen.
- Lot
- Forex trade size: standard 100,000 units, mini 10,000, micro 1,000.
- Risk per trade
- The share of your account you accept losing if the stop-loss is hit, usually 1-2%.
Position sizing turns a stop-loss into a fixed amount of money. Decide what share of the account one trade may lose, measure the stop in pips, and the lot size follows. The calculator converts the pip value into your account currency automatically when your account is in either currency of the pair.
The formulas
Money at risk = balance × risk %. A pip is 0.0001 of the quote currency (0.01 for pairs quoted in yen). Pip value of one standard lot (100,000 units) = 100,000 × pip size, in the quote currency: 10 USD for EUR/USD, 1,000 JPY for USD/JPY. Convert it to the account currency (divide by the price when the account is in the base currency), then lots = money at risk ÷ (stop pips × pip value per lot).
| Lot | Units | Pip value, EUR/USD |
|---|---|---|
| Standard | 100,000 | $10.00 |
| Mini | 10,000 | $1.00 |
| Micro | 1,000 | $0.10 |
Limits
A stop can fill beyond its price in a fast market or over a weekend gap, and spreads and swap costs are not included. Brokers' minimum lot sizes vary (many allow 0.01 lots).
Key takeaways
- Lots = (balance × risk %) ÷ (stop pips × pip value per lot).
- 1 standard lot = 100,000 units.
- USD-quoted pairs: $10 a pip per standard lot.
- Risking 1-2% a trade is common.
Frequently asked questions
How do I calculate lot size in forex?
Divide the money you will risk by the stop-loss in pips times the pip value of one lot. Risking $100 with a 25-pip stop on EUR/USD ($10 a pip per lot): 100 ÷ (25 × 10) = 0.40 lots.
How much is one pip worth?
For one standard lot of a pair quoted in US dollars, $10. For USD/JPY, 1,000 yen, which is about $6.67 at 150. Mini lots are a tenth, micro lots a hundredth.
What lot size for a $1,000 account?
Risking 1% ($10) with a 20-pip stop on EUR/USD: 10 ÷ (20 × 10) = 0.05 lots, i.e. 5 micro lots.