How Perpetual Funding Rates Work

Why funding exists at all

A perpetual swap has no expiry date, which is what makes it convenient. But a contract with no settlement date has nothing forcing its price to match the underlying spot market. Funding is the fix.

The funding rate is a small periodic payment exchanged directly between long and short traders — the exchange doesn't take it. When the perpetual trades above spot, longs pay shorts, which discourages buying and nudges the price back down. When the perpetual trades below spot, shorts pay longs, encouraging buying and pulling the price back up. This tug-of-war keeps the perp price anchored to spot without an expiry to do the job.

Who pays whom

The direction of payment depends on the sign of the rate:

• Positive funding rate: the market is net-long and the perp trades at a premium. Longs pay shorts.
• Negative funding rate: the market is net-short and the perp trades at a discount. Shorts pay longs.

Crucially, you only pay or receive funding if you are holding a position at the exact funding timestamp — commonly every 8 hours on many venues, though intervals vary by exchange and can be more frequent. If you open and close entirely between two funding times, you pay nothing. This is why funding matters far more to swing and position traders than to quick scalpers.

How the rate is calculated

Funding is generally built from two parts: an interest rate component (usually small and fixed) and a premium component that measures how far the perp is trading from the underlying index price. When the perp premium is large, the premium component dominates and the rate climbs.

The amount you actually pay is the rate applied to your position's notional value, not your margin. That distinction matters enormously with leverage. If you hold $10,000 of notional exposure funded by $1,000 of margin at 10x, funding is charged on the $10,000. A rate that looks tiny against notional can be a meaningful percentage of your actual collateral. RektCalc's funding-related tools let you estimate this cost against your real position size.

How funding quietly affects your P&L

Funding is a silent line item. Your position can be flat on price but slowly bleeding from repeated funding payments if you're on the paying side. Over days of holding, that can add up to a real drag — and it's a common reason a trade that looked break-even ends up in the red.

The flip side is that funding can also be an edge. Some traders deliberately position on the receiving side, or run delta-neutral setups (long spot, short perp, or a hedged pair across venues) specifically to collect funding while carrying little directional risk. Extreme funding is also a sentiment signal: very high positive funding means the crowd is aggressively long and possibly over-leveraged, which can precede sharp long-liquidation flushes.

Worked example: what funding actually costs you

Say you open a $20,000 notional long on a BTC perpetual with $2,000 margin (10x leverage). Funding is currently +0.01% per 8-hour period — a fairly typical level. You hold for 3 days, so 9 funding events pass:

$20,000 × 0.0001 × 9 = $18

Against $20,000 notional that looks trivial. But measured against your actual $2,000 margin, it's 0.9% gone in under a week — before price has moved at all. Now stretch the same trade into a funding spike of +0.05% per 8h (common during strong bull runs) held for 5 days (15 events):

$20,000 × 0.0005 × 15 = $150

That's 7.5% of margin, enough on its own to turn what looked like a break-even trade into a loss. The lesson: funding scales with your notional and your leverage, not with how much you put down — so the more leveraged the position, the more funding can eat relative to your actual capital at risk.

Common mistakes

• Comparing exchanges by trading fee alone. A venue with a 0% maker fee can still be the more expensive place to hold a position if its funding rate consistently runs hotter than a competitor's.
• Confusing predicted funding with realized funding. Most exchanges show an estimated rate ahead of the settlement timestamp that can still shift before it's actually charged — don't treat it as locked in.
• Closing right before the funding timestamp to dodge it, then reopening after. The round-trip trading fees and slippage from doing this every 8 hours usually cost more than the funding they're meant to save.
• Assuming a hedge across two venues is funding-neutral. If both legs happen to carry positive funding at the same time, you're paying twice, not netting to zero — check both rates, not just the spread.

Practical takeaways

• Check the current and predicted funding rate before holding overnight. A position you'd keep at zero funding may not be worth it at a steep rate.
• Remember funding is charged on notional, not margin. Leverage multiplies the effective cost relative to your collateral.
• You only pay if you hold across the funding timestamp. Timing matters for short holds.
• Treat extreme funding as a crowding signal, not a guarantee — it tells you how one-sided positioning is, not what price will do next.

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Frequently asked questions

Does the exchange keep the funding payment?

No. Funding is paid directly between long and short traders. The exchange facilitates the transfer but does not collect the funding itself (it earns from trading fees separately).

How often is funding charged?

It depends on the exchange. Many venues settle funding every 8 hours, but some use 4-hour, 1-hour, or other intervals. You're only charged if you hold a position at the funding timestamp.

Is a high funding rate good or bad for me?

It depends on your side. High positive funding is a cost if you're long and income if you're short. It also signals heavily one-sided long positioning, which can raise the risk of a liquidation cascade.

Can I avoid paying funding altogether?

Only by not holding a position at the funding timestamp — either close before it or open after it. Some traders also seek out venues or pairs where the current rate favors their side, but rates change frequently and can flip before your next hold period.