Prop Lot Size turns your account, risk, and stop into a lot size — and checks it against your prop firm's daily-loss and drawdown limits before you enter. Answers to common questions are below; for anything else, reach out directly.
You enter your account balance, risk (as a percentage or a fixed dollar amount), stop distance, and instrument, and the app calculates your position size in lots. Pick your prop firm and account configuration too, and it checks the trade against that firm's daily-loss and maximum-drawdown limits — showing a clear green (within limits), amber (close), or red (would breach) verdict, plus the largest lot size that still fits.
The app computes how much loss room your firm's rules leave you — the tighter of your daily-loss allowance and your maximum-drawdown floor — and compares your trade's risk against it. It handles static, end-of-day-trailing, and intraday-trailing drawdown types. Enter today's loss so far and your drawdown anchor for an exact reading. Lot sizes are always rounded down to the 0.01 broker step, so you never exceed the risk you asked for.
The app ships researched rule sets for 15+ major prop firms, each labeled with the date it was last reviewed. Firms change rules often and some let you configure limits at checkout — so the app lets you enter your own limits, which always take precedence over the bundled values. Treat the shipped rules as a starting point and confirm your real limits with your firm; the app never claims to know a firm's current published rules, only that a trade fits the rule set you selected or entered.
Free — the calculator with a starter set of USD-quoted instruments and firms and one saved account, fully offline. Pro ($8.99/mo or $59.99/yr) — every instrument and prop firm, unlimited saved accounts, breach warnings, custom firm rules, and trade-card export, still fully offline. Pro+ Live ($14.99/mo) — adds a live MetaTrader 5 connection through SignalDeck that auto-fills your balance, equity, and drawdown for a real-time remaining-room guard.
The live connection is part of the Pro+ Live tier. You sign in with your SignalDeck account, and the app reads your linked MT5 account's balance, equity, and drawdown through SignalDeck's backend to fill the calculator automatically. The app never asks for your broker login and never contacts your broker directly — everything routes through SignalDeck, which owns the MetaTrader integration.
Open Settings on your iOS device → tap your name → Subscriptions → Prop Lot Size → Cancel Subscription. You keep access until the end of the current billing period. All billing, renewals, and cancellations are handled entirely by Apple — see our Terms of Use for details.
Open Prop Lot Size, open the upgrade screen from any locked feature, and tap Restore. As long as you're signed into the same Apple ID that made the original purchase, your subscription restores automatically. Your saved accounts and custom rules live on-device, so they stay put unless you delete the app.
On Free and Pro, no — there's no account, no sign-in, and no analytics or tracking SDKs, and everything runs offline. The optional Pro+ Live tier connects to your SignalDeck account to read your MT5 balance and drawdown. See the full Privacy Policy for exactly what the app does and doesn't handle.
Bug reports, feature requests, and general questions about Prop Lot Size.
linkedin.com/company/sgnldk →Prop Lot Size is made by SignalDeck, a trading journal for forex and prop firm traders.