R multiple

One R is the money you risked on a trade. A win of twice the risk is +2R, a full stop-out is −1R, and a scratch is around 0R. Expressing results in R makes trades comparable across different account sizes and time periods.

R is the natural input to expectancy, and it removes the distortion that account growth otherwise introduces into a track record. It also makes losing runs legible: 'down 6R this month' says more than a cash figure.