
PropSize: Lot Size Calculator
Position sizing for prop firms
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Free
In-App Purchases
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About
Position sizing for prop traders.
Enter your balance, risk and stop loss to estimate a lot size. PropSize brings position sizing, configurable prop-firm loss-limit context and shareable trade cards together in one iPhone app.
• Calculate forex, gold and supported index position sizes.
• Use a stop distance in pips or enter entry and stop prices.
• Type your own risk percentage or use quick adjustments.
• Choose your firm and account type, with optional broker overrides.
• Try a guided calculation before exploring subscription options.
• Speak trade inputs using Apple's speech recognition, or type them.
• Copy your lot size or share a trade card.
Loss-limit context compares a single estimated trade risk with your configured initial account size and limit. PropSize does not connect to a trading account, track today's losses or open positions, or calculate remaining drawdown. Estimates exclude spread, fees and slippage. Currency conversions use reference rates, which may be cached. Broker contract and volume rules can vary; optional overrides are available.
Subscriptions
Choose a monthly or annual subscription. Eligible customers may receive the trial displayed at checkout. Apple determines eligibility. The price, trial and renewal terms are shown before confirmation. Subscriptions renew unless cancelled. Purchases and restores require an internet connection; some calculations can use cached rates.
PropSize is a calculation tool, not financial advice. It does not guarantee a firm's rules are current or that a trade will avoid a breach.
Privacy: https://propsize.app/privacy
Terms: https://propsize.app/terms
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What's New in PropSize
1.1.2
October 6, 2026
A clearer first calculation, smoother position sizing and more reliable checkout recovery. • Guided first-use tips point to the controls you need. • Standard sizing works without mandatory broker setup. • Custom risk entry, stop-price inputs and result-sheet spacing are improved. • Purchase and restore recovery is improved. • Optional app-usage sharing can be changed in Settings. • Speech permission wording now explains that Apple may process audio.
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Subscriptions & In-App Purchases
PropSize Monthly
Prop-firm-aware position sizing
$8.991 Month
3 Days trial







