Worked example
Take three hypothetical spot inputs: $60,000 at 50% weight, $60,100 at 30% and $59,900 at 20%. The weighted index is $30,000 + $18,030 + $11,980 = $60,010. These weights are illustrative; real exchanges maintain constituent, outlier and outage rules that can change the calculation.
Using Swolecharts
The basis explainer connects a reference price to a futures premium. The BTC Hyperliquid funding page displays that venue's oracle alongside its mark; an oracle serves a reference role but is not necessarily the same index used by a centralised exchange.
Common confusion
An index is not an order book you can trade against. A $60,010 reference does not imply enough liquidity exists to execute your whole order at $60,010.
Checked against exchange documentation on 13 October 2026: Bybit: index price calculation. Examples are illustrative, not live market readings.