Position Size / Margin Calculator
Most people decide how much to buy first and then white-knuckle the loss — that's backwards. The disciplined way is to decide the most you'll lose on this one trade first, then work back to how big the position should be. Enter your capital, the per-trade risk you can stomach, your entry and your stop, and the tool below gives you the position size and the margin it ties up once leverage is on. This is a risk-management tool, not investment advice.
How it works: this is a risk-management tool that works back from the loss you can accept to a position size — not investment advice. Risk amount = capital × per-trade risk%; risk per unit = |entry − stop|; position size = risk amount ÷ risk per unit; notional value = size × entry; margin required = notional ÷ leverage. Note: the higher the leverage, the closer the liquidation price sits to your entry and the greater the risk — leverage scales the size of your position, not your win rate. The math leaves out fees, funding, and slippage, and your stop can fill away from the price you set (gaps, slippage). This tool runs entirely in your browser — nothing is sent, uploaded, or stored.
How this tool does the math
The core is a backwards idea: first decide "if this trade goes wrong, the most I'll lose is X." That's the risk amount, equal to your capital times the per-trade risk percentage you set. A lot of steady traders keep per-trade risk to 1%–2% of capital. Then look at the gap between your entry and your stop — that's what you lose per unit of the asset if price reaches the stop. Divide the risk amount by that gap and you get the largest position you can take without blowing the budget. Size times entry is the notional value, and notional divided by leverage is the margin it ties up.
Say capital is 1,000, you're willing to lose 1% (10 USDT), entry is 2,000, stop is 1,900. Risk per unit is 100 USDT, the position is about 0.1 units, notional is about 200 USDT — on spot with no leverage that's covered outright. Turn on 5× leverage and the margin drops to about 40 USDT, but be clear that leverage didn't change your max-loss budget; it just brings liquidation on faster.
How to turn this number into a decision
Treat the position it gives you as a ceiling, not a target — it's "the most you can take without breaking the risk budget," and you're free to size down. If hitting the profit you want means putting on a huge position and tying up a lot of margin, that usually means the stop is set too wide or the risk is set too high, and the move is to go back and adjust the inputs, not to crank up leverage. To get clear on how spot and futures differ on leverage and liquidation, see spot vs futures.
Nothing here is investment advice. Reference: Binance Help Center (margin and liquidation). Margin rules and the liquidation mechanism follow whatever Binance's official page shows at the time.