PropSize is a free, browser-based prop firm position size calculator for futures and CFD/forex-style accounts. It is built for traders who fail challenges because of size — not setups.
What we care about
- Daily-limit aware risk — size against the number that ends the day.
- Always floor — never round up into breach territory.
- Honest market labels — Apex & Topstep are futures-only; FundedNext offers CFDs and futures with different leverage and loss rules.
What we are not
We are not a broker, prop firm, signal service, or financial advisor. We do not place trades, manage money, or sell signals. Nothing here is financial advice — it is arithmetic you could do on paper, done faster.
How this site makes money
The calculator is free and always will be. There is no account, no email wall, and no paid tier. Two things keep it online:
- Display advertising. Ads may appear between sections. We do not choose the individual advertisers and an ad is not a recommendation.
-
Affiliate links. Some links to prop firms are referral links. If you buy an
evaluation after clicking one, we may earn a commission at no additional cost to you.
Those links are labelled Affiliate link where they appear and are marked
rel="sponsored"in the page source.
What that money does not buy: the calculator's output. The maths is identical whether a firm pays us or not, the numbers are not tilted toward partners, and firms with no commission are still listed and still get presets. We also keep the parts that cost firms customers — the warnings about trailing drawdown, the leverage trap, and the plain statement that most challenge accounts fail.
PropSize is independent. We are not owned by, employed by, or officially partnered with Apex, Topstep, FTMO, FundedNext, or any other firm named on this site, and a referral relationship does not make us their representative. Verify every rule with the firm itself before you trade.
Contact
Questions, corrections, or partnership: hello@propsize.app (replace with your real inbox before launch if different).