How Funding Rates Work on Aster: Formula, Intervals and a Worked Example (2026)

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Funding on Aster is a payment between traders on the same perpetual contract, made at each settlement and sized as position size times mark price times the rate. When the rate is positive, longs pay shorts. When it is negative, shorts pay longs. Aster does not keep any of it, and each market settles on its own interval.

The rest of this page covers what Aster's documentation says about how the rate is computed, the cap and the interval, then works one real settlement through to a USDT amount. It is the explanation behind the funding column on the markets hub and the realized figures on the Aster funding rate history page. It covers mechanics only. Nothing here says whether to hold a position through a settlement.

Which side pays funding on Aster?

The docs define it in two lines. A positive funding rate means the contract price is above the mark price, and long traders pay short traders. A negative rate means the contract price is below the mark price, and short traders pay long traders.

The purpose, in the docs' words, is to keep the contract price close to the underlying spot price. While the perp trades above the mark, holding a long costs money at each settlement and holding a short earns it.

Two details from the same page affect how it lands on your account. First, funding comes out of your Perps Account balance. If that balance is short, the docs say the fee may be taken from position margin instead, which can move your liquidation price. The arithmetic of that is in how liquidation works on Aster. Second, settlement timing is not exact to the second. The docs warn of a 15-second deviation between the actual time and when the fee is charged, and give the example of a position opened at 16:00:05 UTC that may still be charged for that interval.

How is the Aster funding rate calculated?

The formula, as the docs print it:

Funding Rate (F) = [Average Premium Index (P) + clamp(interest rate − P, 0.05%, −0.05%)] / (8/N)

interest rate = 0.01% (0% for BNBUSDT)
N = funding interval in hours

Read it in three parts.

The premium index measures how far the order book sits from the index price. Aster computes it every 5 seconds as [max(0, impact bid − index) − max(0, index − impact ask)] / index. The index price is a weighted average of prices from external spot exchanges, and the impact bid and ask are the average prices to sell or buy a fixed notional against current book depth. Over a settlement period these samples are averaged into P. For markets on an interval longer than 1 hour, later samples carry more weight (sample n is weighted n). For 1-hour markets, it is a simple average.

The clamp adds the difference between the interest rate and the premium, limited to a band of 0.05% either way. One consequence follows from the algebra: whenever the premium is within 0.05% of the interest rate, the clamp passes the whole difference through, P cancels, and the rate before the divisor is just the interest rate. That is why many settlements print the same flat figure. Of the last 12 BTCUSDT settlements the API returned on October 26, 2026, covering October 23 to 27 UTC, 8 read exactly 0.0100%.

The divisor (8/N) scales the result to the market's interval. At N = 8 it is 1. At N = 4 it is 2, so the flat rate becomes 0.005% per settlement, which is what ASTERUSDT printed at four of its six settlements on October 26, 2026. At N = 1 it is 8. The docs use ASTERUSDT on a 4-hour interval as their own example.

There is one gap between the docs and the API here. The docs give the interest rate as 0.01% for every market except BNBUSDT. The fundingInfo endpoint reports an interestRate per symbol, and on October 26, 2026 it listed 574 symbols at 0.01%, 8 at 0.005% and 216 at 0, BNBUSDT among them. The zeros include stock and commodity perps such as XAUUSDT and TSLAUSDT. Where the two disagree, the endpoint is what the engine reports for that market today.

Mark price versus index price

The rate depends on the index price through the premium. The payment depends on the mark price. The mark price page says funding payments between longs and shorts are calculated using the mark price, which is the median of three numbers: the index adjusted for the funding rate and time to the next settlement, the index plus a 5-minute moving average of the mid-price basis, and the last contract price. The same mark price values your unrealized PnL and triggers liquidation.

What caps the funding rate?

Two separate limits apply. The clamp above bounds only the interest-rate term, at 0.05% either way. The overall rate per settlement has a cap and a floor set per market. The docs do not print these values. They say Aster may adjust the cap, the floor and the interval during extreme volatility, and that no announcement is made when an interval changes because the rate hit its cap or floor.

The values are published by the public fundingInfo endpoint as fundingFeeCap and fundingFeeFloor. Read on October 26, 2026:

The funding rate history page lists the cap and floor under every featured market, refreshed each build.

How often is funding settled on Aster?

It depends on the market. The docs call 8 hours the default, but more than half of the listed markets run on a shorter clock, and a calculation that assumes 8 hours everywhere will be wrong for them. The fundingInfo endpoint listed 798 symbols on October 26, 2026:

Intervals also change over time. Our API reference recorded SUSHIUSDT settling hourly on September 8, 2026. On October 26 the endpoint reported it at 8 hours. The interval shown on the market today is the one that applies.

Because of the 8/N divisor, the rate per settlement is already scaled to the interval. A flat 0.01% on an 8-hour market and a flat 0.005% on a 4-hour market describe the same daily cost: 0.03% a day either way. Comparing the raw per-settlement numbers across two markets with different intervals tells you nothing until you multiply each by its settlements per day.

If you scale a rate to a year, the only correct multiplier reads the interval:

annualized = rate per settlement × (24 / interval hours) × 365

Applied to the flat rates above, 0.01% × 3 × 365 and 0.005% × 6 × 365 both come to 10.95%. That is arithmetic on a constant rate, not a forecast, since real settlements move with the premium every period. Assuming 8 hours for an hourly market understates its yearly figure 8 times over. The history page and the market pages on this site read the interval for each market instead of assuming it.

Worked example: one ASTERUSDT long through a real settlement

This uses live data only, with the assumptions written down.

The market. ASTERUSDT, which fundingInfo reported on a 4-hour interval with a ±2% cap on October 26, 2026.

The settlement. The fundingRate endpoint returned a rate of 0.00029514 (0.029514%) for the ASTERUSDT settlement at 04:00 UTC on October 26, 2026. It is positive, so longs paid shorts.

The mark price. The markPriceKlines endpoint gave a mark of 0.70017608 USDT at the open of the 04:00 UTC minute.

The position. Long 10,000 ASTER on the perp, so notional at mark = 10,000 × 0.70017608 = 7,001.76 USDT.

Funding amount = position size × mark price × funding rate
               = 10,000 × 0.70017608 × 0.00029514
               = 2.0665 USDT   (paid by the long, received by a short)

A short of the same size would have received the same 2.0665 USDT.

That one settlement was well above the market's flat 0.005%. The full day looked like this:

The table holds notional fixed at 7,001.76 USDT to keep the arithmetic visible. In practice each settlement uses the mark price at that moment, so the USDT amounts would differ slightly as ASTER moved. Two of the six settlements account for about two-thirds of the day's total. The other four sat at the flat 0.005% the formula produces when the premium stays within the clamp band.

What funding means for a hedged position

A hedged position here means holding the asset on spot and shorting the same amount on the perp. The two legs move in opposite directions on price, so a rise in ASTER that gains on the spot leg loses roughly the same on the short, and a fall does the reverse. What does not cancel is funding, because only the perp leg pays or receives it:

• When the rate is positive, the short leg receives funding at each settlement.
• When the rate is negative, the short leg pays funding at each settlement.

So a hedge like this swaps price exposure for funding exposure. Using the day above, a 10,000 ASTER short against 10,000 ASTER on spot would have received 4.2604 USDT across the six settlements at fixed notional. On a day of negative settlements, the same position pays.

Several costs sit on top of the funding flow, and the documented ones can be put in numbers. At the base rates, for a 7,001.76 USDT leg:

All-taker, opening and closing both legs once costs 11.2028 USDT, or 0.16% of one leg's notional. The perp half of that, 0.08%, is the base-tier round trip shown for Aster on the Perp DEX Fee Index. ASTERUSDT is a Crypto General perp on the docs' fee page, not a Group B pair, so the 0.04% base taker rate applies. VIP tiers lower it, and the spot docs list a 5% reduction for paying spot fees in ASTER.

Other costs are real but have no fixed number:

• Slippage and spread on four fills. The fee table assumes every fill happens at the quoted price.
• Basis. The perp's PnL is valued at the mark price and the spot leg at the spot price. The two are close but not identical, so the hedge is never exact, either while it is open or at the close.
• Liquidation risk on the short. The spot holding sits in your spot balance, and funding comes out of the Perps Account. If price rises, the short leg loses margin even though the spot leg gains, and the short can be liquidated on its own. The mechanism is in the liquidation guide.
• The sign of funding. A run of positive settlements can turn negative, and then the short pays.

None of this is a suggestion to run the trade, and this page gives no expected return for it. It explains why a hedged position still has a funding line on it, and what that line is net of. The full construction, both collateral layouts and 90 days of settlements on five markets are in delta-neutral hedging on Aster.

Does 1001x mode work the same way?

No. 1001x mode trades against the ALP pool, and its fees page says funding is calculated every block, with separate long and short rates set by the gap between long and short open interest and the platform's borrow rate. The accumulated fee shows up in unrealized PnL and feeds straight into the liquidation price. Shield Mode has its own hourly formula too. Everything above this section applies to order-book perps in Pro mode, the markets listed on the markets hub.

Where to read the current and past rates

• On Aster. The docs point to two pages on asterdex.com: a real-time funding rate page and a funding rate history page, which show each market's current interval and its cap or floor.
• On this site. The Aster funding rate history page sums 30 and 90 days of realized settlements for every featured market, interval read per market. Each market page, such as ASTER, shows funding for that market and its interval.
• From the API. GET https://fapi.asterdex.com/fapi/v1/fundingRate?symbol=ASTERUSDT returns settled history in ascending order, 100 rows by default and up to 1,000 per request, per the API docs. GET /fapi/v1/fundingInfo returns the interval, cap and floor. Both are public and need no key. The API reference shows the response shapes.

This page describes a mechanism. It does not tell you whether to open, hold or hedge anything. Aster is a self-custodial venue with no legal entity named in its terms, and this site is an independent guide with a referral relationship, as set out on the disclaimer. If you are new to the order ticket, how to trade on Aster covers the wallet, the deposit and the first order.

Sources & Citation

How these figures were verified

• Aster official documentation: Funding Rate (Perpetuals, Fees & Specs) — which side pays at a positive or negative rate, the funding rate formula with its clamp and 8/N divisor, the 0.01% interest rate and the BNBUSDT exception, the premium index and its 5-second sampling, the funding amount formula, the default 8-hour interval and Aster's right to change cap, floor and interval, the 15-second timing note, and the deduction from the Perps Account balance or position margin. Checked October 26, 2026.
• Aster official documentation: Mark Price — how the index price and mark price are built, and the statement that funding payments are calculated using the mark price. Checked October 26, 2026.
• Aster official documentation: Fees (Perpetuals) — the 0% maker and 0.04% taker base rates for Crypto General perpetuals, and the Group B list that ASTERUSDT is not on. Checked October 26, 2026.
• Aster official documentation: Spot Fee Structure — the 0.005% maker and 0.04% taker base spot rates used for the spot leg of the hedged example. Checked October 26, 2026.
• Aster official documentation: API Documentation — the GET /fapi/v1/fundingRate endpoint, its startTime, endTime and limit parameters, and the 100-row default and 1,000-row maximum. Checked October 26, 2026.
• Aster official documentation: Shield Mode Funding Fee Rate — the hourly Shield Mode funding example (05:12 to 05:59 pays nothing, held to 06:00 pays) cited in the FAQ. Checked October 26, 2026.
• Aster official documentation: 1001x Fees & Slippage — the statement that 1001x funding is calculated every block and feeds into unrealized PnL and the liquidation price. Checked October 26, 2026.
• Aster public futures API: fundingInfo — the interval counts across 798 listed symbols (103 at 1 hour, 3 at 2 hours, 361 at 4 hours, 331 at 8 hours), the per-symbol interest rates, the 4-hour interval and plus or minus 2% cap for ASTERUSDT, and the 8-hour interval and plus or minus 0.3% cap for BTCUSDT. Checked October 26, 2026.
• Aster public futures API: fundingRate (ASTERUSDT) — the six ASTERUSDT settlements on October 26, 2026 (UTC) used in the worked example, including 0.029514% at 04:00 UTC. Checked October 26, 2026.
• Aster public futures API: markPriceKlines (ASTERUSDT) — the 0.70017608 USDT mark price at the open of the 04:00 UTC minute on October 26, 2026. Checked October 26, 2026.
• Asterpedia — the worked example and the fee arithmetic, derived from the formula and the rates above with the assumptions stated; the 0.08% perp round trip matches the Perp DEX Fee Index. Checked October 26, 2026.

Aster revises its fee schedules, leverage caps and token mechanics regularly, so every figure here is a dated snapshot rather than a live feed. Where a number comes from Asterpedia’s own tracking rather than the documentation, it is labelled as such above.

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Asterpedia. "How Funding Rates Work on Aster: Formula, Intervals and a Worked Example (2026)." Published October 26, 2026; last updated October 26, 2026. https://asterpedia.com/guides/trading/how-funding-rates-work-on-asterCopy

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