ROAS & CAC Payback
Once you've connected Stripe and imported your ad spend, Signal Sparrow can answer the three money questions every marketer cares about — using real revenue, not platform estimates.
The three numbers
ROAS (Return on Ad Spend)
How much revenue each dollar of ad spend brought in.
ROAS = Revenue ÷ Spend
Because the revenue side comes from Stripe, this is your true ROAS — not the inflated version ad platforms report for themselves.
CAC (Customer Acquisition Cost)
How much it costs, on average, to win one paying customer.
CAC = Spend ÷ New paying customers
CAC Payback
How many months of a customer's revenue it takes to earn back what you spent acquiring them.
CAC Payback = CAC ÷ Monthly revenue per customer
A shorter payback means you get your money back faster and can reinvest sooner.
Why it needs ad spend
All three compare money in to money out. Signal Sparrow already knows the "money in" from Stripe — you just need to give it the "money out" by importing your ad spend. Until then, revenue shows but ROAS and CAC can't be calculated.
Read it per channel
Every number is available per channel, so you can see that (for example) LinkedIn has a higher CAC but a faster payback than Meta — and decide where the next dollar should go.
For subscription businesses, CAC payback is often the truest health check. A channel with mediocre first-month ROAS can still be excellent if those customers stay and pay for many months.