The most common sizing mistake on futures is to start from the leverage: "I'll put up 1,000 USDT and open it at 20x." That tells you how big the position is. It does not tell you what you lose if the stop is hit. The right order is the other way round. First decide how much you are willing to lose, then let the stop distance set the size, and only then pick a leverage, which changes nothing but the margin you tie up.
Three numbers are enough
To size a position you need three things:
- Risk: the amount you accept losing if the stop is hit. Most traders set it as a fixed share of the account, for example 1%.
- Stop distance: the gap between your entry price and your stop price.
- Fees: what you pay to get in and to get out at the stop. You pay them on a losing trade too.
The formula is:
size = risk ÷ (|entry − stop| + entry × entry fee + stop × exit fee)
Leverage is not in it, and it should not be.
A worked example
Your account holds 10,000 USDT and you risk 1% a trade, so 100 USDT. You want to go long BTCUSDT at 100,000 with a stop at 98,000. The fee is 0.05% each way, the regular taker rate on Binance USD-M futures.
| Line | How it is worked out | Amount |
|---|---|---|
| Stop distance | 100,000 − 98,000 | 2,000 USDT |
| Entry fee (per unit) | 100,000 × 0.05% | 50 USDT |
| Exit fee at the stop (per unit) | 98,000 × 0.05% | 49 USDT |
| Risk per unit | 2,000 + 50 + 49 | 2,099 USDT |
| Position size | 100 ÷ 2,099 | 0.04764 BTC |
The position is worth about 4,764 USDT. If the stop is hit you lose 95.28 USDT on price and 4.72 USDT in fees, 100 USDT in total.
Forget the fees and size at 100 ÷ 2,000 = 0.05 BTC, and the same stop costs you 104.95 USDT. A 5% overshoot looks small, but it grows as the stop gets tighter. With a stop 0.5% away, fees add about 20% to the loss.
You can run your own numbers in the free position size calculator: enter the entry, the stop, the amount you want to risk and your fee rates, and it gives the size with fees included.
What leverage changes
Open the same 0.04764 BTC position at different leverage:
| Leverage | Margin tied up | Loss at the stop |
|---|---|---|
| 2x | 2,382 USDT | 100 USDT |
| 5x | 953 USDT | 100 USDT |
| 20x | 238 USDT | 100 USDT |
The loss is the same on every row. Leverage only changes how much margin the exchange sets aside for the position. Low leverage ties up more margin; high leverage frees it up but does not make the loss any bigger.
Sizing from the leverage does make the loss bigger. Put up 1,000 USDT at 20x and the position is 20,000 USDT. The same stop 2% away now costs 400 USDT before fees, 4% of the account and four times what you planned.
Too much leverage switches your stop off
On isolated margin, the only thing behind a position is the margin you gave it. Before that margin runs out, the exchange closes the position for you: a liquidation. The higher the leverage, the closer the liquidation price sits to your entry.
At 50x in the example, the margin is about 95 USDT and a 2% fall takes nearly all of it. Binance closes a position before its margin reaches zero, to keep the maintenance margin, so the liquidation comes before your stop at 98,000. The stop never fires, the position is liquidated, and you pay a liquidation fee on top.
A simple rule: on isolated margin, your liquidation price should sit comfortably beyond your stop. The order form shows the liquidation price, so compare it with your stop before you place the order.
Write the plan in your journal
A position size is a plan, and only a record shows whether the plan held. If you note the planned stop and risk on every trade, you can read each result in R: risk 100 USDT and make 250, and the trade was 2.5R. The trades where you lost more than planned at the stop show up too. Usually those are the ones where you forgot the fees, slippage ate into the fill, or you widened the stop after entry. For how to read R, see R-multiples explained.
Connect your Binance futures to a free Viktury journal and each trade's PnL includes the fees and funding it really paid.
What Viktury does with it
When you add a Binance account in Viktury, your trades sync every day. If the key has Enable Futures, your futures trades come in with the fees and funding they paid. Add your planned stop and risk to a trade and Viktury shows the result in R, worked out from the real PnL with fees and funding, not from the price difference alone.
Open a free Viktury account and add your Binance key.