Position size calculator (forex, AUD-native)
Calculate the exact lot size to trade based on your account balance, risk per trade, and stop loss in pips. Built AUD-first for Australian traders. ASIC retail leverage caps surfaced as warnings when your inputs imply oversized positions.
Calculator
All values stay in your browser. Output recalculates instantly as you type. Copy the URL to share or bookmark a configuration.
- 33,333 units
- $100.00 at risk (1%)
- 20 pip stop loss
How position sizing works
Position sizing is the single highest-impact decision in any trade. Most retail accounts blow up not because the strategy is wrong, but because the size is wrong. Get sizing right and you survive long enough to learn whether your edge is real. Get it wrong and the math will compound against you faster than any setup can compensate for.
The mechanics are simple: define how much you are willing to lose if the trade hits stop, then back-solve for the lot size that produces exactly that loss. Everything else (entry, exit, target) is downstream of that one number.
The four inputs
- Account balance. The total capital in the account, in your account currency. AUD for an Australian-based account at FP Markets, Pepperstone, IC Markets etc.
- Risk percentage. The share of the account you are prepared to lose if the stop is hit. Standard institutional convention: 1 to 2 percent. Lower is safer, higher is faster ruin.
- Stop loss distance. The number of pips from entry to your stop. This is a function of the pair's volatility and your strategy's edge, not a number you pick to make the trade fit.
- Currency pair. Determines the pip value per lot in your account currency, after FX conversion.
The formula
The denominator is what trips most people up. Pip value is not the same as pip size. Pip size is the price increment (0.0001 for most pairs, 0.01 for JPY pairs). Pip value is the dollar amount one pip move represents on a one-standard-lot position, which depends on the quote currency and your account currency.
For a one-standard-lot EUR/USD position with a USD account, one pip is worth $10. For the same position with an AUD account, one pip is worth roughly $15.30 at an AUD/USD rate near 0.65. The calculator handles this conversion automatically.
Worked example
An Australian trader has $10,000 AUD at FP Markets. They want to take a EUR/USD long with a 25 pip stop loss, risking 1 percent of the account.
- Risk amount = $10,000 x 0.01 = $100 AUD.
- Pip value per standard lot in USD = 100,000 x 0.0001 = $10 USD.
- Pip value per standard lot in AUD = $10 USD / 0.6540 (AUD/USD) = $15.29 AUD.
- Position size = $100 / (25 pips x $15.29) = 0.26 standard lots (or 26,000 units).
If the stop is hit, the loss is 25 pips x 0.26 lots x $15.29 per pip per lot ≈ $99.40 AUD. Within the 1 percent risk envelope.
Why 1-2% per trade
This is not folklore. It is statistical math.
Assume a strategy with a 50 percent win rate and a one-to-one reward-risk ratio. Even a fair coin produces losing streaks. The probability of an eight-loss streak across 100 trades at 50 percent win rate is roughly 64 percent. At 1 percent risk per trade, eight consecutive losses produces an 8 percent drawdown. Recoverable. At 5 percent risk, the same streak produces a 40 percent drawdown, which requires a 67 percent gain on the remaining capital just to break even.
Drawdown recovery math is non-linear. A 50 percent loss requires a 100 percent gain to recover. A 75 percent loss requires a 300 percent gain. Once you are below 60 percent of starting capital, the path back is mathematically improbable for most strategies. The 1-2 percent rule exists to keep the recovery math survivable.
ASIC leverage caps and implied leverage
The calculator surfaces a warning when your configured inputs imply more leverage than ASIC permits for retail clients on Australian-licensed brokers.
| Asset class | ASIC retail cap | Examples |
|---|---|---|
| Major FX pairs | 30:1 | EUR/USD, USD/JPY, GBP/USD, AUD/USD, USD/CAD, USD/CHF, NZD/USD |
| Minor FX + gold | 20:1 | EUR/AUD, AUD/JPY, GBP/AUD, XAU/USD |
| Major indices | 20:1 | S&P 500, ASX 200, FTSE 100, NASDAQ 100 |
| Minor indices | 10:1 | Smaller national indices |
| Commodities (ex gold) | 10:1 | WTI oil, silver, copper |
| Crypto CFDs | 2:1 | BTC, ETH |
| Single stock CFDs | 5:1 | Apple, Tesla, BHP, CBA |
If a position-size calculation produces an implied leverage above the cap, the broker will reject the order at execution unless you are wholesale or Pro classified. Reduce the risk percentage or widen the stop loss to bring the implied leverage back inside the cap.
Related calculators
- Pip value calculator - what one pip is worth in AUD on any pair and lot size.
- Margin calculator - how much margin a position locks up at a given leverage.
Related guides:
- How to trade forex in Australia (step-by-step) - full nine-step framework, calculators slot into Step 5.
- ASIC-regulated forex brokers - the brokers where these leverage caps actually apply.
- Best forex brokers in Australia 2026 - full broker comparison.
Frequently asked questions
A position size calculator tells you exactly how many lots to trade based on your account balance, the percentage of capital you are willing to risk on the trade, your stop loss distance in pips, and the currency pair. The formula is: lots = risk amount divided by (stop loss pips multiplied by pip value per lot). The output is the largest position you can take while keeping the dollar loss capped at your defined risk if the stop is hit.
Most professional and institutional risk frameworks cap risk at 1 to 2 percent of the account balance per trade. At 1 percent risk, an account survives roughly 100 consecutive losing trades before reaching zero. At 5 percent risk, the same account is wiped out in around 20 losses. The 1-2 percent rule exists because losing streaks are statistically inevitable and drawdown compounds non-linearly above 2 percent.
Multiply your account balance by your risk percentage (as a decimal). Divide that by (stop loss pips multiplied by AUD pip value per lot). For an AUD account trading EUR/USD with a $10,000 balance, 1 percent risk, and 20 pip stop, the calculation is: $100 risk divided by (20 pips x $15.30 per pip per lot in AUD) = 0.33 lots.
Under the ASIC Product Intervention Order in force since March 2021, retail clients trading forex with an Australian-licensed broker are capped at 30:1 leverage on major currency pairs (EUR/USD, USD/JPY, GBP/USD, AUD/USD, USD/CAD, USD/CHF, NZD/USD). Minor pairs and gold are capped at 20:1. Wholesale and Pro-classified clients can access higher leverage but must meet income, asset, or trading-experience thresholds.
Small position size outputs are usually a sign that the risk formula is working as designed. Typical retail traders are surprised by how small their lots should be at 1 percent risk with realistic stop distances. If the size feels too small, the answer is to grow the account, not to inflate the risk percentage. Position size scales linearly with account balance at fixed risk percentage.
Yes. JPY pairs use 0.01 as the pip size (the second decimal place) instead of 0.0001 used by most other pairs. The calculator handles this automatically when you select a JPY pair from the dropdown. Pip value math, position size math, and ASIC leverage classification all adjust accordingly.
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