Funding rate calculator for crypto perpetual futures

How funding is charged

A perpetual future has no expiry, so nothing forces its price back to spot the way settlement does for a dated contract. Funding does that job instead. At fixed timestamps one side pays the other in proportion to position notional: above the index the rate is positive and longs pay shorts, below it the rate turns negative and shorts pay longs. It is a transfer between traders, not a venue fee.

The formula

periods        n = holding hours / interval hours
settlements    s = floor(n)
cost           C = notional × rate × n
charged        between  notional × rate × s
                   and  notional × rate × (s + 1)
annualised     rate × (8760 / interval hours)
on margin      C / (notional / leverage)
break-even     entry × (1 + C / notional)

The single most important property is that funding is charged at instants, not continuously. Open after a settlement and close before the next one and you pay nothing, however long the position felt. Hold across three settlements and you pay three times. This is why the calculator shows a smooth estimate and the two integer outcomes around it: the real charge depends on the minute you opened relative to the venue clock.

It also means a quoted rate cannot be compared across venues without its interval. A rate settling every hour costs eight times what the same printed number costs settling every eight hours, for the same position held for the same time. This is the mistake the comparison table exists to prevent: it holds the position, the leverage and the holding time identical across rows, so the entire difference in the cost column comes from the rate and interval you entered.

Annualising has the same dependency. Multiplying a per-interval rate by the number of intervals in a year gives a figure that is comparable to a borrowing cost, which is genuinely useful — carrying a leveraged perpetual is a financing decision, and the annualised number is the one to hold against alternatives. But an annualised rate quoted without its interval is not a number at all, and the two are always shown together here.

Leverage does not change what funding costs. The charge is a percentage of position notional, and notional is set by the size you opened, not by the margin behind it. What leverage changes is how that cost feels: the same charge measured against a tenth of the margin is ten times the proportion of your capital. A funding cost that looks negligible against notional can be a large fraction of the margin actually at risk, and that is the number in the second readout.

What the formula assumes

The rate itself is usually built from an interest-rate component and a premium component tracking how far the perpetual trades from the index, with the result clamped to a cap. The practical consequence is that funding measures current positioning rather than forecasting anything: a high rate says the book is crowded on one side, and it can invert quickly when that crowd unwinds.

The sign convention in this tool follows the market. A positive rate with a long position is a cost; the same rate with a short position is income, and the outputs turn green and change sign accordingly. Persistent negative funding on a short is a real source of return, and it is one of the reasons basis and carry strategies exist — but it is also the crowded trade whose unwind moves the rate.

Everything else about holding the position sits outside these numbers. Trading fees on entry and exit, slippage, the spread between mark and index at your fill, and any cost of financing the collateral itself are all excluded. For a short hold the trading fees usually dominate funding entirely; for a long hold funding usually dominates the fees. The break-even output tells you only how far the price has to move to cover the funding, not to cover the trade.

Questions

Do I pay funding if I close before the settlement?

No. Funding is exchanged only between accounts holding a position at the settlement timestamp. A position opened and closed entirely between two settlements pays nothing, which is why the calculator reports the number of full settlements alongside the cost.

Why does the same rate cost more on one venue than another?

Because the rate is quoted per settlement interval. A rate settling hourly is applied eight times as often as the same number settling every eight hours, so it costs eight times as much for the same holding period. Comparing rates without comparing intervals is the most common error in venue comparisons.

Does higher leverage increase my funding cost?

Not in absolute terms. Funding is charged on position notional, so the cost depends on the size you opened, not the margin behind it. Higher leverage means the same cost is a much larger share of your margin, which is what the cost-against-margin output measures.

Why are the intervals editable instead of fixed?

Because they are not constants. They differ by venue, they differ between contracts on the same venue, and they change. Hard-coding them would produce confident, wrong comparisons. Set each row to the schedule of the contract you actually trade.

Background

What this calculation is actually measuring

The calculator does the arithmetic. The guide explains the mechanism underneath it: where the number comes from, what has to be true for it to hold, and the point at which it stops describing the market in front of you. If you are going to act on a figure this page produced, that is the page to read first.