Forex Position Size Calculator
Size every trade by your account risk and stop loss. Risk by percentage or fixed amount, stop loss in pips or by price – the calculator returns the exact number of units, lots, and pip value for the position.
Three numbers determine position size: how much money you accept to lose, how far away your stop loss is, and how much one pip is worth on one unit of the base currency in your account currency.
risk_amount = balance × risk_percent / 100 pip_value_per_unit = pip_size × (quote_ccy → account_ccy rate) loss_per_unit = pip_value_per_unit × stop_distance_pips position_units = risk_amount ÷ loss_per_unit
The result is the number of units of the base currency you should trade. Divide by 100,000 for standard lots, 10,000 for mini, 1,000 for micro. Live rates are pulled from the AlphaScala price feed; cross-currency conversions go through USD.
Account: $10,000 USD · Risk: 1% ($100) · Pair: EUR/USD · Stop: 25 pips
Pip value per unit on EUR/USD with a USD account is 0.0001 USD. Loss per unit if stop is hit: 0.0001 × 25 = $0.0025. Position size: $100 ÷ $0.0025 = 40,000 units (0.4 standard lots).
Verification: at 0.4 lots, pip value is $4. A 25-pip move against you = $100 = exactly your 1% risk. ✓
Account: €5,000 EUR · Risk: 2% (€100) · Pair: USD/JPY · Stop: 40 pips
Pip size is 0.01 (JPY-quoted). Pip value per unit needs USD/JPY → EUR conversion. Calculator handles the cross-rate via the live snapshot – output is the unit count that produces exactly €100 of exposure if the stop hits.
What is position size in forex?
Position size is the number of units of the base currency you buy or sell on a single trade. It determines pip value, margin required, and how much money you lose if your stop loss is hit. The right position size is the one that limits your loss to a pre-decided fraction of your account balance.
How is position size calculated?
Position size in units = risk amount ÷ (stop distance in pips × pip value per unit in your account currency). The risk amount is what you accept to lose on the trade – typically 0.5–2% of your account balance. The pip value per unit depends on the pair and your account currency.
How much should I risk per trade?
Most professional risk frameworks limit risk per trade to 0.5%–2% of account equity. At 1% risk a trader can survive 100 consecutive losers in theory, which is enough headroom for any realistic strategy drawdown. Risking 5%+ per trade is the fastest way to blow up an account during a normal losing streak.
Can I use a price-based stop instead of pips?
Yes. Switch the stop-loss input to "By price" and enter your entry and stop prices. The calculator converts the distance to pips automatically using the correct pip size for the pair (0.01 for JPY-quoted, 0.0001 otherwise) and computes position size from there.
Why does the calculator output show fractional lots?
Most retail brokers accept fractional lots (e.g. 0.42 standard lots = 42,000 units). If your broker only accepts whole lots, round down to the nearest acceptable size – never round up, since that breaches your risk limit.