Enter your account balance, risk percentage, stop-loss distance, and currency pair. The calculator does the rest — no signup, no data leaves your browser, and no live rate is fetched for you.
Position-size calculator
Enter your account balance and stop-loss distance above to calculate.
Educational tool, not investment advice. Verify the calculation and your broker's minimum lot size before placing a trade.
How the Position-Size Calculator Works
Position sizing answers one question: how many lots can you trade so that a full stop-loss costs exactly the dollar amount you decided to risk, not more and not less? Everything else about a trade — entry timing, target selection, whether the setup is any good — is separate from this. Sizing is pure arithmetic, and getting it wrong quietly changes your real risk without changing anything on your chart.
The calculator above takes four inputs — account balance, risk percentage, stop-loss distance in pips, and the currency pair you’re trading — and converts them into a lot size. Selecting a pair sets the pip value per standard lot automatically: USD-quoted majors (EUR/USD, GBP/USD, AUD/USD, NZD/USD) use a fixed $10 per pip per standard lot, so no extra input is needed. JPY-quoted pairs, USD/CAD, USD/CHF, and EUR/GBP need one additional number — the current exchange rate — because their pip value isn’t natively in US dollars. You type that rate in yourself; the tool never fetches or assumes one. A “Custom / other” option is available for instruments not in the list, where you supply the USD pip value per lot directly.
The Formula
The underlying formula is the same one worked through in our risk management guide:
Lots = (Account balance x Risk %) / (Stop-loss in pips x Pip value per lot)
Dollar risk is the balance multiplied by the risk percentage. Dividing that by the stop distance times the per-lot pip value gives the lot size that makes the stop-loss cost exactly that dollar amount. The result is rounded down to the nearest 0.01 lot, because that’s the smallest increment most brokers accept — rounding up would mean risking more than you specified.
Why 1–2% Risk Per Trade
The 1–2% figure that pre-fills the calculator isn’t a rule the tool enforces; it’s a starting point most retail risk plans use, and the reason is streak arithmetic rather than tradition. A run of eight consecutive losses is not a rare event over a few hundred trades at a sub-50% win rate — it happens often enough to plan around. At 1% risk per trade, eight straight losses cost roughly 7.7% of the account. At 2%, the same streak costs roughly 14.9%. At 5%, it costs over 33%, and recovering a 33% drawdown requires a 49% gain just to get back to even, because the gain is calculated on a smaller base after the loss. Our risk management guide works through the full recovery-math table and streak-probability numbers behind this. The calculator doesn’t pick a number for you — it shows you what a given risk percentage costs in lots and dollars so you can decide with the arithmetic in front of you instead of a hunch.
Worked Example
Take a $2,000 account, 1% risk per trade, a 50-pip stop-loss, on EUR/USD. EUR/USD is USD-quoted, so the pip value per standard lot is fixed at $10 — no rate entry needed.
- Dollar risk: $2,000 x 1% = $20
- Lots: $20 / (50 pips x $10) = 0.04 lots
Switch the same trade to USD/JPY with a USD/JPY rate of 150.00 entered, and the pip value per lot works out to roughly $6.67 instead of $10 (JPY pips are ¥1,000 per standard lot, converted at the entered rate). The same $20 dollar risk and 50-pip stop then produces a larger lot size, because each pip is worth less in USD. This is exactly why a flat “$10 per pip” assumption is wrong for JPY pairs and crosses — see lot sizes explained for the full breakdown of why pip value depends on the quote currency.
Currency Pairs Supported
The dropdown covers eleven named pairs across four quoting conventions, plus a custom option:
- USD-quoted, no rate needed: EUR/USD, GBP/USD, AUD/USD, NZD/USD
- JPY-quoted, needs the current USD/JPY rate: USD/JPY, EUR/JPY, GBP/JPY, AUD/JPY
- CAD/CHF-quoted, needs the current USD/CAD or USD/CHF rate: USD/CAD, USD/CHF
- GBP-quoted, needs the current GBP/USD rate: EUR/GBP
- Custom / other: enter the pip value per standard lot manually — useful for gold, indices, or any instrument with a non-standard contract size
If you want to see the pip-value arithmetic broken out on its own, separate from the lot-size calculation, use the pip-value calculator.
Frequently Asked Questions
Why does the calculator ask for a currency pair instead of just a pip value?
Because the correct pip value per lot changes depending on the pair’s quote currency, and typing it in by hand is where most sizing errors come from. Selecting the pair applies the right pip size and, for pairs that need one, prompts for the specific rate that converts it into US dollars — the same rate you’d use anyway, just without the extra manual multiplication.
Does this calculator fetch live exchange rates?
No. It runs entirely in your browser and never makes a network request. For pairs where a conversion rate is needed — JPY crosses, USD/CAD, USD/CHF, EUR/GBP — you enter the current rate from your own broker or data feed. The output stays blank until you provide it.
What lot size should I actually use if the calculator gives me an unusual number?
Round down to your broker’s minimum increment, which is usually 0.01 lots. If the computed size is below that minimum, the calculator tells you rather than silently rounding up — widen the stop, lower the risk percentage, or increase the account balance instead of over-risking to hit a round lot size.
Is 1% or 2% risk per trade correct for my account?
There’s no single correct number; it depends on your win rate, your stop distance, and how large a drawdown you can tolerate without changing your behavior. What the arithmetic does tell you is that going meaningfully above 2% shortens the number of consecutive losses needed to produce a damaging drawdown. See the risk management guide for the streak-probability tables behind that trade-off.
Why does the position size shrink after I switch from EUR/USD to a JPY pair?
It doesn’t necessarily shrink — it changes because the pip value per lot changes. A JPY pip converted at a typical rate is usually worth less in USD than the fixed $10 on a USD-quoted major, so for the same dollar risk and stop distance, the lot size that produces that risk is often larger, not smaller. Compare the “Pip value used” line in the result to see exactly what the calculator applied.