How do I calculate cash on cash return for a BRRR

[Steven Haller]

Do i calculate cash on cash return on the cash left in deal after refi or also on the cash I used to purchase the property?

Here is a simplified scenario:

100k to purchase and repair.

Refi after 1 year; new loan amount 75k.

Cash left in deal 25k

Net income (after mortgage) 10k year.

Do I calculate ROI on the 25k left in deal or on the 100k total used to purchase the property.

(numbers are not a real deal, I am just trying to understand how to calculate my return).

Thanks.