Size a trade from the loss you can accept.

• Shares = (account size x risk %) / (entry price - stop price), rounded down to whole shares, then capped by the largest-position setting.
• Dollars at risk is the loss if the stop fills exactly at the stop price. Real fills can be worse: prices can gap past a stop (overnight, on news or after a halt), and fees, spreads and slippage aren't included.
• Reward to risk (R) = distance from entry to target / distance from entry to stop. It describes one setup's arithmetic, not how likely the target is.
• Educational arithmetic only. Coteau doesn't pick trades, prices or stops, and nothing here is advice.
• Every number is hypothetical and depends entirely on what you enter. Small changes in assumptions can change results a lot.
• Returns are smooth and constant in the single-number projection; real returns vary every year, and real markets can do better or worse than anything shown.
• Inflation is a single constant rate you choose (except in historical replays, which use the actual CPI of each year).
• Growth compounds monthly (or at the contribution frequency) and contributions are made at the end of each period.
• No taxes unless you turn on the simplified tax drag (all positive growth taxed each year at your rate, which overstates tax for buy-and-hold). No fees unless you set one.
• Inputs stay in your browser. Saving uses this device's local storage; a share link contains the numbers you entered, so anyone with the link can see them.

S&P 500 return presets: Aswath Damodaran (NYU Stern), Historical Returns on Stocks, Bonds, Bills, Real Estate and Gold (histretSP.xls), annual S&P 500 total returns with dividends 1928-2025, compound (geometric) averages; inflation from the CPI-U (FRED CPIAUCNS) in the same file.

Coteau may be wrong. Check every number yourself, and talk to a licensed professional before acting on anything.