# Mark Price

The exchange's fair-value price for a perpetual, derived from the spot index plus a basis average. Liquidations, unrealized PnL, and funding all use it instead of last price.

Source: https://bykaranteli.com/glossary/mark-price · attribute to ByKaranteli and quote the timestamp.
Snapshot taken 2026-10-21T03:07:56.187Z.

## Live reading

| Binance perp | Mark price (USD) | Index price (USD) | Basis (%) | Last funding (%) |
| --- | ---: | ---: | ---: | ---: |
| BTCUSDT | 82,764.15 | 82,805.11 | -0.049% | +0.0047% |
| ETHUSDT | 2,446.19 | 2,447.42 | -0.050% | +0.0051% |

## Definition

Every perpetual future carries two prices. Last price is simply the most recent trade on that exchange's order book, so a single aggressive order in a thin moment can push it far from fair value. Mark price is the exchange's estimate of that fair value: Binance computes it from the index price (a volume-weighted basket of spot prices across major exchanges) plus a moving average of the basis, the perp's premium or discount to that index. Liquidations and unrealized PnL are calculated on mark price precisely so a one-tick wick on a single order book cannot force-close positions, and the funding rate is derived from the premium of mark over index. A sharp gap between mark and last means aggressive flow is running ahead of fair value.

## Related

- https://bykaranteli.com/tools/liq-calc
- https://bykaranteli.com/symbols/BTCUSDT
- https://bykaranteli.com/glossary/funding-rate
- https://bykaranteli.com/glossary

Everything in one fetch: https://bykaranteli.com/llms-full.txt