Win-rate & profit calculator
Win rate alone is a trap. This calculator turns win rate and reward-to-risk into the numbers that actually matter: expectancy, profit factor, break-even win rate, and projected P&L over many trades. Free and instant.
What "R" means
R is your risk unit — the dollar amount you lose if a trade hits its stop. Expressing wins and losses in R makes any strategy comparable. An "avg win of 2R" means winners make twice what losers cost. Pair this with the position sizing calculator to turn 1R into a real position size.
The math behind each number
expectancy & profit factor# Expectancy in R per trade
expectancy = (winRate × avgWin) − (lossRate × avgLoss)
= (0.45 × 2) − (0.55 × 1) = 0.35 R
# Profit factor = gross win / gross loss
profit_factor = (0.45 × 2) ÷ (0.55 × 1) = 1.64
# Break-even win rate for a given reward:risk (RR)
break_even = 1 ÷ (1 + RR) # at 2:1 → 33.3%
A strategy that wins only 45% of the time can be highly profitable if its winners are twice its losers. Conversely, a 70%-win-rate "high accuracy" bot can lose money if its rare losses are huge. Never judge a bot by win rate alone.
How to use this with the backtester
- Run a strategy on the backtester and read off its win rate.
- Estimate its average win and loss in R from the trades.
- Plug them in here to project performance over hundreds of trades.
- If expectancy is negative, the strategy loses money long-term — no matter how good a few trades looked.
Frequently asked questions
How do you calculate trading expectancy?
Expectancy = (win rate × average win) − (loss rate × average loss). Expressed in R (multiples of risk), a positive expectancy means the strategy makes money on average over many trades, even if individual trades lose.
What is a good win rate for a trading bot?
Win rate alone is meaningless without reward-to-risk. A 40% win rate with 2:1 winners is profitable; a 70% win rate with tiny winners and big losers is not. Focus on expectancy and profit factor, not win rate.
What is profit factor?
Profit factor = gross profit ÷ gross loss. Above 1.0 is profitable; 1.5+ is solid; 2.0+ is excellent. It tells you how many dollars you make for every dollar you lose.
What is break-even win rate?
The break-even win rate is the minimum win percentage needed to not lose money at a given reward-to-risk ratio. At 2:1 you only need to win about 33% of trades; at 1:1 you need over 50%.