Prop Risk Sizer: Position Size Calculator for Prop Firm Challenges (Excel + Google Sheets)

Most failed challenges don't end on a bad trade. They end on arithmetic: a daily floor you didn't know had moved.

The Prop Risk Sizer tells you, before every trade, the most you can risk without breaching today's floor. It then sizes the position, rounded down to your lot or contract step, so rounding never takes you over the line.

HOW IT WORKS

- Pick a rule preset or type your own: daily loss %, where it's measured from (day-start balance, or the higher of balance and equity), max loss %, and static, end-of-day trailing or intraday trailing drawdown.

- Each session, enter day-start balance and equity and keep current equity updated.

- The board shows your daily floor, overall floor, which one binds, room left, your own safety buffer, and max risk on the next trade.

- Pick the instrument and stop distance to get the size.

WHAT'S INSIDE (6 tabs)

- Preflight: the board, plus a quick-size panel. OK / HOLD / STOP status.

- Size a Trade: a 40-row planner with instrument, stop, size, actual risk, % of account and % of usable room.

- Stress Test: for risk from 0.25% to 3% per trade, how many full losses in a row you can take before the daily and overall limits.

- Rule Presets: 13 presets read from firms' public rule pages (FTMO, FundingPips, The5ers, FundedNext, Topstep, Apex), each dated with a source link, plus 4 slots for your own.

- Instruments: major forex pairs (JPY, CHF and CAD pip values update with price), gold and silver CFDs, index CFDs, and CME minis and micros (ES, MES, NQ, MNQ, YM, MYM, RTY, M2K, CL, MCL, GC, MGC), plus 6 custom rows.

- Start Here: setup in five gates, plus how each floor type works.

AN HONEST NOTE

Firms change rules, so the presets are dated and you should always confirm against your own dashboard. CFD contract sizes vary by broker, so check yours. Nothing can make anyone pass an evaluation. This removes the failures that were arithmetic, not trading. Educational tool, not financial advice. Not affiliated with or endorsed by any prop firm.

Works in Microsoft Excel and Google Sheets (File > Import). Instant download, no subscription.