Position size and risk-reward calculator
Position size is how much you can buy so that, if your stop is hit, you lose only the share of your account you chose to risk. Enter your account size, the percent you will risk, your entry and your stop. The calculator gives the size, the dollar risk and the reward-to-risk ratio. It runs in your browser.
Nothing you type leaves your browser. This is arithmetic, not advice.
How it is calculated
size = (account size x risk percent) / distance from entry to stopWorked example. You have $10,000 and risk 1%, so $100 is at risk. You buy Bitcoin at 50,000 with a stop at 49,000. The stop is 1,000 away, so the size is $100 / 1,000 = 0.1 coin. The position is worth $5,000, which is half the account. With a target at 53,000 you stand to make $300, which is 3 times the risk, so the reward-to-risk ratio is 3 : 1.
Reward-to-risk is the distance to the target divided by the distance to the stop. A ratio above 1 means the target is further away than the stop.
What it leaves out
- Fees and slippage. They are not in the sum, so a stopped-out trade can lose slightly more than the amount shown.
- Gaps. A stop is a plan, not a guarantee. A fast market can fill it at a worse price.
- Funding. On a perpetual future you pay or earn funding while the position is open. What funding is.
- Leverage and margin. The size is the same with or without leverage. If the position is worth more than your account, you need leverage or margin to open it, and the calculator says so.
The calculator does not recommend a risk percent. That number is yours to choose.
Questions
How do I calculate position size?
Multiply your account size by the percent you will risk to get the dollar risk. Divide that by the distance between your entry and your stop. The result is the number of units to buy or sell.
What is a good risk-reward ratio?
There is no single good number. It depends on how often your trades win. A ratio of 3 : 1 means a winner pays three times what a loser costs, so you can be right less often and still come out ahead. Test your own record before you decide.
Does this work for shorts?
Yes. Put the stop above the entry and the target below it. The calculator reads the direction from the stop.
Are my numbers saved or sent anywhere?
No. The calculation runs in your browser.
Chart your levels
Draw your entry, stop and target on a chart with 81 indicators, and set an alert on the stop. How alerts work.