Compare perpetual funding and forex overnight swaps using the same position value, holding period and currency. A funding rate shown “per interval” is not directly comparable with a broker's daily swap amount, and neither is the whole cost of trading.
Perpetual funding can be a payment or receipt between position holders. Forex rollover or overnight financing follows the broker's contract and schedule. The sign, calculation base, cut-off and number of charged days all matter.
Write the units beside every rate
A rate of 0.01% every eight hours means something different from 0.01% per day. A broker may quote a swap in points or an amount per lot rather than a percentage. Convert it using the contract size, point value and account currency specified by that broker.
Bybit's funding guide describes a rate that can change until the settlement time and warns that settlement frequency can change. VALR's own-venue futures guide describes hourly funding, while its third-party Perps terms defer to the relevant execution infrastructure. Do not apply one interval to every contract with a similar name.
A one-day and seven-day worksheet
These are invented assumptions, not current provider rates. Assume a constant R100,000 notional position, no price or currency movement, a long position paying funding, and no compounding.
| Model | Assumed charge | One day | Seven days |
|---|---|---|---|
| Perpetual | 0.01% each eight-hour interval | 3 × R10 = R30 | 21 × R10 = R210 |
| Forex position | R25 per chargeable day | R25 | 7 × R25 = R175 |
The forex row assumes seven chargeable daily equivalents, regardless of how the broker groups them. It does not assume every calendar night has one separate debit. Weekend and holiday treatment must come from the actual contract schedule.
Now add hypothetical entry and exit costs of R40 each for the perpetual and R60 each for the forex position. Total modelled seven-day costs become R290 and R295 respectively. Funding alone made the forex example look cheaper; the assumed complete cost reverses that small difference.
This comparison does not say the positions have equivalent market risk. A currency pair and a crypto asset can behave very differently. The worksheet only compares specified charges.
Changing rates require event-by-event calculation
If three perpetual intervals have rates of +0.01%, -0.02% and +0.015%, a long position with constant R100,000 notional pays R10, receives R20 and pays R15: net cost R5. Do not average signs away or describe the negative interval as a fee you paid.
If position size or mark price changes, recalculate the notional for each event. If funding is charged in USDT, retain the USDT amount and use a documented rand conversion for reporting. A rand estimate today is not necessarily the rand value of the actual historical charge.
Align the clocks
Africa/Johannesburg is UTC+2. An illustrative 00:00, 08:00 and 16:00 UTC schedule maps to 02:00, 10:00 and 18:00 in South Africa. These are conversion examples, not a claim that every contract uses that timetable.
A broker using UK local time introduces another issue: the UK changes clocks seasonally. IG's South African costs document, dated November 2023 and still served at the linked URL when checked, describes overnight charging by reference to UK time. Check the applicable date and convert the cut-off; do not hardcode a year-round South African hour from a winter observation.
Keep an auditable cost record
Record contract, direction, quantity, notional, rate units, settlement timestamp, charge currency and the actual debit or credit. Add spread, commission, conversion and any other applicable charges separately. Avoid counting a spread both inside the execution price and again as a cash fee.
Funding credits are not guaranteed yield. Price losses and liquidation can exceed a small funding receipt, and rates can reverse. The exchange hub and cash-out hub provide platform and rand-exit context, while the SARS guide covers broader records.
Before applying the worksheet, replace its assumed rates with the chosen contract's current funding interval and the broker's rollover calendar. Reconcile the result to actual debits and credits, including any changed position size.
Sources and verification
Primary sources checked on 20 September 2026. Prices, availability and processing arrangements can change.