**Payback period is the amount of time it takes to earn back your investment in Rebilly (also known as the break even point).**

It takes your estimated price (your cost in Rebilly) and measures it against your estimated recovered gross profits.

Your estimated price is $225.

**Then, we calculate the gross profit value of a single recovered invoice. **

That is your average transaction value ($10) multiplied by your gross profit margin (80%) which gives us $36.

10 x 80%= 8

So you earn an additional $8 in gross profit for each invoice that is recovered.

**Now, we need to figure out how many invoices must be recovered to earn the estimated price of $225. **

To do that, we take $225 and divide it by $8 and round up to the nearest integer. That gives us 28.

450 / 36= 28.12 round up --> 28

So, when 28 invoices are recovered, you break even.

Finally, we estimate how long it will take to recover 13 invoices.

To do that, we use our estimate of how many invoices will be recovered within the first month (35), and take it as a percentage of that. That yields 28/35 which is 8% of the month. If we convert that to days, using 30 days as a typical month (and rounding up) we get 12 days as the payback period time.

3 days is the payback period time.