Tools
Prop challenge calculator: room to the limits and path to target
Pick a firm's program or enter the rules yourself, then set risk, RR and win rate. The calculator shows how many stops stand between you and failing, how many winners between you and the target, and how many trades that takes on average.
What the calculator computes
Prop firm limits are percentages of the starting balance, so risk per trade is taken from the starting balance too: a streak of stops adds up linearly. The stop on which the day ends = daily limit ÷ risk, rounded up; the same for max loss. Winners to target = target ÷ (risk × RR).
With a win rate W, expectancy per trade = risk × (W × RR − (1 − W)) percent of the account, and average trades to target = target ÷ expectancy. Days = trades ÷ trades per day, but never fewer than the firm's minimum days.
Example: FTMO 2-Step, phase 1
Rules from the Trading OS registry (checked against ftmo.com on 2026-09-23): 10% target, 5% daily limit, 10% max loss, 4 minimum trading days. A $100,000 account, 1% risk = $1,000, RR 2, 45% win rate.
The daily limit is hit on the 5th stop in a row, max loss on the 10th. Without a single stop, 5 winners reach the target. Expectancy is 1% × (0.45 × 2 − 0.55) = 0.35% per trade — about 29 trades to target; at 2 trades a day that's about 15 trading days.
Why an average isn't a guarantee
Expectancy says where the account drifts on average, but it doesn't cancel streaks: at a 45% win rate, five stops in a row do happen. If your room to the daily limit is shorter than a typical streak, the risk per trade is too big for these rules.
A trailing drawdown (Topstep, Apex, FTMO 1-Step) pulls the floor up behind a growing balance — after profit, the room is smaller than a static calculation shows. Consistency rules and restrictions (news, weekend holding) aren't modeled here — they're listed on the firm pages.
Frequently asked questions
- What risk per trade should I use on a challenge?
- Count your room: with a 10% max loss, 1% risk gives you 10 stops in a row, 0.5% gives 20. The smaller the risk, the longer the road to target — and the longer the streak the account survives.
- Where do the firm presets come from?
- From the Trading OS rules registry: every number is checked against the firm's public page, with a check date and a link. Where a firm contradicts itself, the field is left out. Rules change — confirm on the firm's site.
- Does the calculator account for the best-day rule?
- No. Consistency rules (for example, at Topstep the best day can be at most 55% of total profit) are listed on the firm page, and the Trading OS journal checks them against the account's real trades.
Track the firm's limits on your real trades
Pick the firm and program for an account in the Trading OS journal — it computes your room to the daily limit, max loss and target from closed trades.
No sign-up — the journal runs in your browser; an account is only needed for sync.