Position Size Calculator

Decide the risk first and let the size follow. Enter your balance, the percentage you are willing to lose on this trade, and where the entry and stop sit — it returns the position that loses exactly that much if the stop is hit.

Size is an output, not a decision

Most losing accounts pick the size first — "I'll put in $2,000" — and discover the risk afterwards. Doing it the other way round fixes the loss and lets the market decide the size: a tight stop earns a big position, a wide stop forces a small one, and either way a stop-out costs the same fraction of the account.

The arithmetic is one line. units = (balance × risk%) ÷ |entry − stop|. On a $10,000 account risking 1%, with entry at $77,000 and a stop at $74,000, you can hold 0.0333 BTC — about $2,567 of exposure, a quarter of the account. Widen the stop and that number shrinks; a $6,000 stop distance would halve it.

Watch the leverage line

When the position value comes out above your balance, the only way to hold it is borrowed money — so the calculator names the multiple you would need. A tight stop on a large account rarely needs any. A tight stop on a small one often implies 5× or more, which quietly converts a risk-managed trade into a liquidation risk. That is the moment to check the liquidation price before the exchange checks it for you.

Questions people ask

1% per trade is the common convention and 2% is the usual upper bound for discretionary trading. The maths behind that: at 2% risk, ten losses in a row cost about 18% of the account; at 5% they cost 40%, which is the territory where recovery needs a doubling rather than a good month.

Yes — put the stop above the entry and the result reads the same. The direction indicator follows the numbers, so if it says "short" when you meant to go long, your stop is on the wrong side.

No, and on a tight stop they matter. Two fees at 0.1% on a $2,567 position is about $5.13 against a $100 risk — five percent of what you meant to lose. On a tighter stop the position is larger and the fee share grows, so leave a little headroom rather than sizing to the last unit.

Other calculators

Stop loss calculator Where the stop goes, and what it costs Risk/reward calculator The ratio, and the win rate it needs Crypto profit calculator Profit, ROI and fees on a closed trade

All nine calculators, or — working the numbers out afterwards is one thing, watching them move is another. TabChart is a free native Windows app that streams live charts straight from 7 exchanges, with no account and no API keys.