Risk management

Risk-Reward Ratio: How to Calculate It Before Each Trade

Astron Team · 09/24/2026 · 6 min read

Many people who start trading focus on just one question: "am I going to win or lose this trade?". But there's an earlier question, equally important, that often gets left aside: "if I lose, how much do I lose, and if I win, how much do I gain?". This comparison is the risk-reward ratio, and it completely changes whether a strategy makes sense in the long run, even if the win rate looks low.

The core idea is simple: before entering any trade, you define an exit point if it goes wrong (the stop) and an exit point if it goes right (the target). The distance between the entry price and the stop is the risk. The distance between the entry price and the target is the potential return. Dividing one by the other gives the risk-reward ratio of that specific trade.

The formula, step by step

The math is: risk-reward ratio = risk in currency ÷ potential return in currency. The result is usually written as a ratio, for example 1:2, read as "risking 1 to gain 2".

Here's a full numeric example. Suppose you buy a stock at R$ 50.00, set the stop at R$ 47.00 (meaning you accept losing up to R$ 3.00 per share) and set the target at R$ 59.00 (expecting to gain up to R$ 9.00 per share). The calculation is:

• Risk per share: R$ 50.00 − R$ 47.00 = R$ 3.00
• Potential return per share: R$ 59.00 − R$ 50.00 = R$ 9.00
• Risk-reward ratio: R$ 3.00 ÷ R$ 9.00 = 0.33, or 1:3

If you bought 100 shares, the trade's total risk is R$ 300.00 and the potential return is R$ 900.00 — the 1:3 ratio stays the same, because it's about the trade, not the position size.

Why the ratio matters more than it seems

Here's the point that tends to surprise beginners: with a good risk-reward ratio, it's possible to be profitable even losing more than half of your trades. Using the 1:3 example above, imagine ten trades, all with the same R$ 300.00 risk and the same R$ 900.00 target:

• If you win only 4 out of 10 trades: gain of 4 × R$ 900.00 = R$ 3,600.00, and loss of 6 × R$ 300.00 = R$ 1,800.00. Result: R$ 1,800.00 positive, even losing 60% of the time.
• If you win 3 out of 10 trades: gain of R$ 2,700.00 and loss of R$ 2,100.00. Result: R$ 600.00 positive, still with a majority of losses.

This example shows why two traders with the same win rate can end up with opposite results: what changes is the size of the gain when they win, compared to the size of the loss when they lose.

Risk-reward ratio doesn't replace win rate

It's important not to overreach with this conclusion: a 1:5 ratio, for example, looks great on paper, but if the target is so far away that the price almost never gets there, the win rate collapses and the strategy stops working in practice. The ideal is to look at both things together — the risk-reward ratio and the strategy's historical win rate — before deciding if it's viable.

There's even a simple calculation to find the minimum win rate a risk-reward ratio requires to avoid a loss: divide the risk by the sum of risk and return. With the 1:3 ratio from the example above, that gives R$ 3.00 ÷ (R$ 3.00 + R$ 9.00) = 0.25, meaning this strategy breaks even by winning just 25% of trades. Any win rate above that already represents a long-term profit, which helps explain why the risk-reward ratio tends to weigh more in the decision than simply counting wins and losses.

How to apply this before every trade

A practical way to build this calculation into your routine is to always follow three steps before confirming a trade:

• Mark the stop price first, based on something technical (a support, a resistance, a moving average), never on how much you're "willing to lose" with no connection to the chart.
• Mark the target based on another plausible technical point, not a random round number.
• Calculate the ratio between the two. If it comes out well below 1:1, ask yourself whether it's worth entering, even if the trade seems to have a high chance of winning.

Many charting platforms, including the one used on Astron, let you draw the risk and reward directly on the chart before confirming the order, which helps visualize this ratio without having to do the math in your head. Even so, no risk-reward ratio eliminates the risk of loss: it's a tool for thinking about probabilities across many trades, not a guarantee of outcome on a single trade.