futurestrading

Open the $BTC perpetual on Binance Futures and you'll see three prices sitting next to each other. Most beginners only watch the big one. That's the wrong habit, because the big one isn't the one that closes your position.
What the BTCUSDT Perp header showed at ~11:55 IST today (Tue, Oct 20):
- Last price: 81,716.7
- Mark price: 81,716.8
- Index price: 81,752.2
- Funding: 0.00998%, next settlement in ~1h35m
- 24h low on the perp: 81,146.4
1. Last price
The price of the most recent trade on that futures contract. It's what the candles on the default chart are drawn from, and it's what moves when someone hits the book with a big market order.
Because it's one venue's trades, last price can wick hard. Today's dip took the perp down to 81,146.4, while Binance spot BTC/USDT bottomed at 81,200 around 06:40 IST. Back on Oct 15, the perp wick reached 79,732.3 while spot held 79,800.
2. Index price
A weighted average of BTC spot prices across several major exchanges. One fat-finger order on one book barely moves it. Think of it as the market's fair spot reference.
3. Mark price
The price the exchange uses to value your open position. Binance builds it from the index plus a smoothed premium, and checks it against last price so it can't drift far from either.
Why it matters:
- Liquidation is triggered by mark price, not last price
- Unrealized PnL on your position is calculated from mark price
- A quick wick on last price that mark price doesn't follow usually won't liquidate you
That's the whole point of mark price: one thin moment on one order book shouldn't wipe out traders.
Where the three connect
The gap between the perp and the index is the premium, and funding exists to pull them back together. Today funding sits right near the 0.01% baseline, which says longs aren't paying up much. When the perp trades well above the index, funding usually climbs and longs pay shorts.
3 practical habits
1. Check your liquidation price against the mark price, not the candle you're staring at.
2. When you set a stop, look at the trigger option. Binance lets you choose Last Price or Mark Price. Mark-based stops ignore some wicks; last-based stops react faster. Pick on purpose.
3. Switch the chart to Mark Price now and then. It's a dropdown on the chart toolbar, and it shows you what your position actually "sees."
Quick sense of scale: today's 24h low gap between perp and spot was about $54, roughly 0.07%. That's nothing at 2x. At 50x, the same 0.07% is about 3.3% of your margin.
Which one were you watching before today: LAST or MARK? Reply below.
For education only, not financial advice. Data: Binance Futures BTCUSDT Perp header and 1H chart, Binance spot BTC/USDT 5m candles, Oct 15 to 20, 2026.
#Bitcoin #FuturesTrading #BinanceSquare