A funding estimate depends on your position notional, the funding rate, the contract's settlement interval, and how many settlement events you are included in. The calculator estimates event count as the whole number of intervals in your holding hours, then multiplies notional by rate and count. That is useful for planning, but it cannot know where your holding period falls on the exchange clock, whether an interval changes, or whether your position is present at the venue's actual settlement time.
Formula used by the calculator
The funding-fee calculator uses:
events = floor(holding hours ÷ interval hours)
funding amount = notional × rate percent ÷ 100 × events × direction
The direction is positive for a long and negative for a short in the tool's displayed amount. In this convention, a positive rate makes a long's estimated amount positive (a cost) and a short's negative (a receipt); a negative rate reverses that direction. The calculator also estimates a daily amount by multiplying the per-event rate amount by 24 ÷ interval hours, and annualizes the entered rate using the same interval conversion.
This calculation assumes a constant notional and one constant rate across the counted events. Actual position notional may move as the mark price changes, and funding rates can change from event to event. The amount is an estimate for the inputs, not a prediction of the next rate.
Worked example: three 8-hour settlements
Suppose a linear perpetual position has $10,000 notional, is long, and the rate is +0.01% for each 8-hour interval. For a 24-hour holding period, the calculator counts:
floor(24 ÷ 8) = 3 events
The estimated funding cost is:
$10,000 × 0.01 ÷ 100 × 3 = $3.00
Each settlement contributes an estimated $1.00 at the assumed notional and rate. A short with the same notional and rate would show −$3.00 under the tool's sign convention, meaning an estimated receipt. If the same position were held for 23 hours, the calculator would count floor(23 ÷ 8) = 2 events and estimate $2.00.
Those event counts are elapsed-time examples, not a claim that a particular exchange settles whenever eight hours have passed since your entry. Suppose the venue's funding times are 00:00, 08:00, and 16:00 UTC. A position opened just before one of those times and kept for only a few minutes could still be included in a settlement. A position held for eight hours that starts just after one funding time might reach the next timestamp near the end of that period. The calculator receives hours and interval, but not the entry timestamp or exchange schedule, so its floor formula cannot resolve that timing difference.
What determines whether a settlement applies
A funding rate is associated with a contract and funding event. Bybit's official help page says funding is paid or received by positions held at the funding time, gives position value × rate as the USDT-contract formula, and notes that pairs can have different intervals. Its page also describes how a funding debit can be taken from available balance and, if that is insufficient for an isolated position, from initial margin. The exact rules and timing are venue-specific, so check the contract page and transaction history for the venue you use. Bybit's funding fee calculation page provides those details for Bybit contracts.
Binance likewise describes funding payments as applying to positions open at specified funding times and notes that its default interval can change under its adjustment rules. It also warns that the transaction may settle with a timing deviation around the nominal time. These details show why an exact boundary is not always captured by an elapsed-hours-only estimate. They are Binance-specific statements, not universal timing guarantees. Binance's funding-rate guide documents its schedule and caveats.
To estimate a real holding plan, check the contract's current rate, the interval for that symbol, the countdown to the next event, and your expected position value at each event. If you expect to scale in or out, the notional held at settlement may not equal your original notional. If the rate is different at each settlement, calculate each event separately or use a conservative range instead of multiplying one rate across the entire hold.
Why the final cost can differ
The actual rate changed. A displayed rate can be an estimate before settlement; the realized rate may differ. The calculator treats the entered rate as fixed. If you are modeling several events, use a separate scenario for each possible rate or update the estimate when new information is available.
The position value changed. In the calculator, notional is held constant. If the contract's relevant mark price changes, the position value used by an exchange may change too. For coin quantity positions, multiplying the quantity by a changed mark price changes notional. A larger notional at a positive rate means a larger long cost in the simplified model.
Your entry or exit straddled a timestamp. The calculator only sees total holding hours. It does not know the wall-clock start and end, exchange timezone, or any processing window. Avoid assuming that under 8 hours always means zero events. Check whether the position was open at the venue's funding time and use its transaction records to reconcile a completed trade.
The contract uses another interval. Funding schedules can vary by symbol and venue and can be adjusted. Do not carry an interval from BTC to another contract without checking. Use the funding rates page to compare displayed rates, then confirm the exact interval and contract terms at the venue.
Funding is only one part of net PnL. A position can move in your favor and still have a lower net result after trading fees and funding. The funding calculator does not include entry or exit fees, slippage, or price PnL. Use the futures PnL calculator when you want a combined estimate and enter its fee and funding assumptions explicitly.
Common mistakes
- Multiplying a rate by elapsed hours without converting the percent to a decimal. For example, 0.01% is 0.0001.
- Assuming the calculator's
floor(hours ÷ interval)predicts a particular venue timestamp. It counts complete elapsed intervals only. - Using one funding rate for a long holding period even though the rate may change at each event.
- Treating leverage as a direct multiplier on the funding fee. In this formula, funding is applied to notional; leverage affects how large that notional is relative to margin.
- Assuming every contract on an exchange has the same interval or timestamp rules.
FAQ
Do I pay funding if I close before the timestamp? It depends on whether the position is still open at that venue's funding event and how its process handles the boundary. Check the contract-specific rule and your history. An elapsed-hours estimate alone cannot answer this.
Does a positive rate mean longs always pay? In the standard convention described by the cited Bybit and Binance guides, a positive rate means longs pay shorts; a negative rate reverses the direction. Verify the sign convention on the venue's contract screen before interpreting a displayed rate.
Does leverage change the funding amount? At a fixed notional and rate, leverage alone does not change the formula's funding amount. It changes the margin used to support that notional, so the same funding payment can represent a larger share of a smaller margin balance.
Why did my funding fee move my liquidation estimate? A funding debit can reduce available balance, and some venues may debit isolated position margin when available balance is insufficient. The effect depends on the venue's rules and account state; the calculator does not update a live liquidation price.
This guide is for educational purposes only and is not financial advice.