The fastest way to know your exact split is to apply — it's free, takes a couple minutes, and you'll see your exact first and second payment amounts right away.
That said, here's how the math generally works so you have a rough sense:
The Split Pay fee:
Every split includes a $9.99 flat fee plus 1.5% of your bill. That gets added to your first payment.
Once Split Pay's share reaches the 50% maximum:
Your first payment is half your bill + the Split Pay fee
Your second payment is the other half
Example: $1,800 rent → $900 + ($9.99 + 1.5% of $1,800 = $36.99) = $936.99 first, $900 second
When you start (Split Pay's share of your bill starts at 30%):
Your second payment is 30% of your bill
Your first payment is the rest of your bill + the Split Pay fee
Example: $1,800 rent, $540 second payment (30%) → $1,260 + $36.99 = $1,296.99 first, $540 second
Split Pay's share grows 5% for each month you pay your second payment on time, up to 50%. Your approved amount — the largest bill Split Pay will split, set 25% above the amount you request — stays the same; what grows is Split Pay's share of each bill. See the FAQ on When will my Split Pay amount go up?.
Apply to see your actual numbers. Applying doesn't commit you to anything, and you'll know your exact split — including fees — immediately.