Step-by-step walkthrough
Use this companion guide beside the interactive calculator to make sure you understand the “why” behind every click. Each section includes the classroom explanation, student-friendly language, and quick practice prompts.
Collect the data points listed below and double-check their units. Keeping an organized “givens” list is one of the fastest ways to reduce math errors and impress exam graders.
Step 1
Enter total spend for the campaign or channel you're measuring, and how many leads it generated in that period.
Step 2
Enter the conversion rate from lead to paying customer for that same cohort — pull this from your CRM rather than guessing.
Step 3
Compare CPA against your customer's lifetime value or average order value to judge whether the channel is actually worth running.
That's a conversion problem, not a lead-generation problem — you're generating cheap leads that don't close. Look at lead quality and your sales/onboarding funnel rather than trying to lower spend further, which would only make it worse.
Only if the leads are comparable in quality and the conversion window is similar — a channel with a longer sales cycle needs more time before its true CPA shows up, so comparing a same-day-conversion channel to a 90-day one too early can be misleading.
