How big should a SOL perp position be on Bitunix with a 500 USDT account and a stop under the 24h low?

Her chart plan puts the stop at 92.00, just under that low. Before clicking, she does what she should have done all along: she sizes the trade from the stop.

The screenshot is the live Bitunix SOLUSDT perp page at 10:17 AM ET: last 94.35, down 6.33%, mark 94.34, index 94.38, 24h high 103.16 and low 92.29, funding 0.0100% with 01:42:31 on the 8 hour countdown, a 15m chart, the order book, and the order panel set to Cross 10X with VIP 0 Maker 0.0200% and Taker 0.0600% shown underneath. Numbers below use the 10:16 prices.

What the old habit would have cost

100 USDT at 10x is 1,000 USDT of position value, about 10.59 SOL. A drop from 94.43 to 92.00 is 2.43 per SOL, so the stop would cost about 25.73 USDT plus roughly 1.18 USDT in taker fees. Close to 27 USDT, or 5.4% of the account, on one idea. Nothing about that number was chosen on purpose.

The sizing steps

1. Pick the risk. Maya uses 2% of equity: 500 x 2% = 10 USDT. Intermediate traders usually land somewhere between 0.5% and 2%. The point is that it is decided before the trade.

1. Measure the stop distance. 94.43 - 92.00 = 2.43 USDT per SOL, which is 2.57% of entry.

1. Price in the fees. Bitunix charges fees on position size, not on margin, and the total cost is the opening fee plus the closing fee. At the VIP 0 taker rate of 0.06%, that is 0.06% x 94.43 plus 0.06% x 92.00, about 0.112 USDT per SOL. Effective risk per SOL: 2.43 + 0.112 = 2.542.

1. Divide. 10 / 2.542 = 3.934 SOL.

1. Round to what the contract allows. The SOLUSDT minimum step is 0.1 SOL, so round down to 3.9 SOL. Position value: 3.9 x 94.43 = 368.28 USDT.

1. Verify. Price loss 3.9 x 2.43 = 9.48, fees about 0.44, total 9.91 USDT. Inside the 10.

1. Choose leverage last. Margin for 368.28 USDT is 122.76 at 3x, 36.83 at 10x, 14.73 at 25x. The loss at the stop is 9.91 in every case.

1. Make sure liquidation is past the stop. At 25x isolated, initial margin is 4% of position value and maintenance margin takes a slice of that, so liquidation sits under 4% away, uncomfortably near a 2.57% stop. At 100x, the SOLUSDT maximum, margin is 1% of value and liquidation lands well inside the stop. At 3x or 10x there is plenty of room.

1. Add funding if the hold is long. At 0.01% every 8 hours, 368.28 USDT pays about 0.04 USDT a settlement while the rate stays positive.

Compared with the old habit, the new size is about a third of the position and loses about 10 USDT instead of about 27 if the stop fills. Same coin, same stop, same chart.

Common mistakes

• Sizing from margin. 100 USDT at 10x tells you nothing about risk until the stop is known.
• Calculating fees on margin. They are on position size, so 10x leverage means ten times the fee of the margin amount.
• Forgetting the closing fee. A stop-market exit is a taker fill.
• Rounding 3.934 up to 4.0 SOL. Small, but it breaks the budget.
• Treating a stop under the 24h low as safe. Today's range was about 11.5% of the price, and lows can be revisited.

The same nine steps carry over to BTC, ETH, XRP or LINK perps on Bitunix. Contract minimums and fee tiers are the only inputs that change.

Quick FAQ

Q: Why not just use 1x? You can. The loss at the stop is identical. You simply lock 368.28 USDT as margin instead of 36.83.

Q: Does a limit entry help? At the 0.02% maker rate the opening fee drops, so step 3 gives a slightly smaller fee per SOL and a slightly larger size.

Q: What if the stop is wider? Size shrinks. A 5 USDT stop distance at the same 10 USDT risk allows under 2 SOL.

Q: Does any Bitunix order limit get in the way? Not here. 3.9 SOL is tiny next to the 10,000 SOL limit on a single market order.