Funding interval
How often is the funding payment settled, and why does that clock matter if a position is held for only hours?
In plain words
The funding interval is how often the funding payment between perpetual futures holders is settled — every eight hours on the exchange that set these rates. A position pays or receives only at those settlements, not continuously.
Why it matters
A hold shorter than one interval may cross no settlement at all, while a hold spanning many intervals collects or pays many. Because each settlement can differ sharply in size, the cost over a week depends on how many settlements a position sits through and on which side it is at each one.
In a real week: BTC, week of 18 January 2021
In the week of 18 January 2021, BTC funding settled every eight hours, roughly 21 times across the week. The average settlement was 0.0446% per eight hours, but the largest was 0.1585% and the smallest was 0.01% — a gap of about sixteen times between the two extremes. That spread means a long held across the week's settlements faced uneven payments, even as BTC fell 9.95%.
A common mistake
Assuming funding accrues smoothly like an interest rate. It arrives in discrete steps, so a position's actual funding cost depends on exactly which settlements it overlaps.