A perpetual contract has no expiry date. What keeps its price tethered to spot is a recurring payment between the two sides of the market, and that payment is the funding rate. It is not a trading fee: the money goes from one holder to another, with the exchange only passing it along. From your account's point of view it has still left.
The difficulty is that it is quoted per interval, while trading fees are quoted per trade. The two units do not compare, which is why the cost of holding a one-sided position for a while gets underestimated so consistently. This tool does the unit conversion — per interval into per day, per period, and an annualised figure — so you can put it on the same scale as everything else.
How to use it, and what the conversion assumes (expand)
Where the numbers come from
Both required fields are on the contract page: the current funding rate and the settlement interval. Take them from the contract you actually plan to trade, since intervals differ between contracts. The rate can be negative; enter it as it is and the tool will tell you which side is paying.
What it calculates
- Daily cost: the per-interval rate multiplied by how many settlements happen in a day.
- Annualised: daily cost times 365, simple interest, no compounding. It exists purely to give you a comparable magnitude.
- Period total: only appears once you enter a notional size and a number of days. It is the funding component alone for that stretch of time.
The assumption, and why it is necessarily wrong
It assumes the rate holds constant across the whole period you entered. It will not. Funding moves with how crowded each side of the market is, can change within a day, and can flip sign entirely. You were paying, and two intervals later you are receiving.
So what comes out is not a forecast. It is an order of magnitude, meant to answer one question: is the funding cost on this position big enough to care about. Any claim that extrapolates a floating rate into a fixed return or a fixed cost is untrustworthy, including the annualised number this tool produces. That is why the assumption is printed in the result rather than buried at the bottom of a help page.
A negative rate is not free money
When funding is negative the direction reverses and shorts pay longs. The tool shows that honestly, but one thing needs saying plainly: opening a long specifically to collect a negative funding rate is a trade a lot of people get wrong.
Two reasons. First, funding usually goes negative because shorts are crowded and price is under pressure — so to collect a small rate you are taking on directional risk of an entirely different magnitude. Second, the rate flips back. Collect for two intervals, start paying on the third, and the earlier receipts go back quickly.
Funding is a by-product of holding a position, not a reason to hold one. The intended use of this tool is "I was going to hold this anyway, how large is this cost", not "which side is paying today".
The settlement timestamp matters too
Funding is charged or paid only on positions open at the moment of settlement. It is not pro-rated by how long you held. Open a position minutes before settlement and close it just after, and you still pay a full interval. Conversely, closing before the timestamp and reopening afterwards skips that interval. At the cost of two extra trading fees.
Which is cheaper depends on the relative size of the funding rate and your fees. Work both out — this tool for one, the effective fee calculator for the other — and compare. In most cases repeatedly opening and closing to dodge one interval is not worth it, but the arithmetic is quick and worth doing once.
What this tool cannot do
It has no market data and no connection to anything. It cannot tell you the current rate for a contract, cannot tell you whether a position is a good idea, and cannot predict where funding goes next. It converts units, and that is the whole of it.
Where funding sits among the other costs
For a position held longer than a few days, funding routinely exceeds the opening and closing fees combined — which is exactly the thing that surprises people who optimised their fee tier. How all the layers fit together is in how fees stack, and the difference in cost structure between spot and futures is in spot or futures.
A converter is not an endorsement
Perpetual and leveraged products can consume your entire margin in a short space of time. This tool exists to make one cost visible, not to suggest you should be holding these positions. Read the risk notice before deciding.