R is the unit trading records should be kept in and almost never are. It answers one question about a closed trade: how many times the risk I took did I make or lose?
How to use it
Enter the entry, the stop you had in place, the exit, and the direction. The calculator returns the risk per unit, the P&L per unit, and the R-multiple.
The arithmetic
initial risk = |entry − stop|
P&L = (exit − entry) × direction (+1 long, −1 short)
R = P&L ÷ initial risk
A long from 100 with a stop at 97 and an exit at 104.5: risk 3, P&L 4.5, +1.5R. The same trade exited at 97: −1.0R. Exited at 98.5, before the stop: −0.5R.
Why it is the only fair unit
A trader with a 10,000 USD account and one with 1,000 USD can run the same strategy. In money, the first has results ten times larger; in percent, both depend on which pairs they traded at what price. In R, the two records are identical if the strategy was followed - and if they are not identical, the difference is the trader, not the account.
This is why every NusaTerminal backtest reports average R, why the automation engine sizes every position to the same R, and why the evidence gate compares strategies in R across every user's results at once. It is the unit in which an edge can be stated and checked.