Perpetual futures calculators
Position size and leverage open on BTC at $83,118, funding -5.04% a year on Hyperliquid; funding cost opens on ETH at $2,668, funding 10.95% a year on Hyperliquid; funding arbitrage opens on JUP, the widest live spread at 72.92% a year. Each is computed on the server before the page is sent — not a blank form waiting for numbers you have to find somewhere else first. Where a formula in common circulation is wrong, the correct result is shown next to it. None of them require an account.
How far the common formula is from the published one
Every row is BTC at its current mark, computed on the server from the venue's own published parameters. The sizes are stated so each figure can be reproduced rather than taken on trust. Why the two columns differ, worked through →
| What is being computed | The formula in circulation | The published parameters | Gap |
|---|---|---|---|
| Liquidation price, 10× long on $10,000 entry × (1 − 1/leverage), which ignores maintenance margin | $74,806.20 | $75,753.11 | 10.00% → 8.86% room from entry |
| Funding on $10,000 held 30 days
the quoted rate read as a daily number, on a venue settling every 1h | $1.73 | $41.45 | 24× |
| Cross-venue funding spread
quoted rates differenced as though the intervals matched | depends on both legs — the calculator shows both readings side by side → | ||
None of this is a claim that other calculators are careless. Reading a quoted funding rate as a daily number is exact only on a venue that settles once a day, and Hyperliquid settles every 1h. The liquidation shortcut is not exact in any tier: it leaves out maintenance margin, which every tier charges. The first margin tier, where the $10,000 BTC position above sits, charges 1.25% — the whole reason its room from entry is 8.86% rather than 10.00% — and the tier for this contract's largest positions charges 2.50%.