CAC (Customer Acquisition Cost)

CAC (Customer Acquisition Cost) is the average amount of money a company spends to acquire one new paying customer. The formula is simple: divide total marketing and sales spend in a given period by the number of new customers won in that period. Despite its simplicity, CAC is one of the most decision-driving metrics in e-commerce, SaaS and any subscription business.

How CAC is calculated

A honest CAC includes every acquisition-related cost, not just ad budgets: salaries of marketing and sales staff, agency retainers, software tools, content production and affiliate commissions. Many teams also track a narrower "paid CAC" (media spend only) to steer campaigns week to week, while the fully loaded CAC informs strategy and pricing.

CAC only becomes meaningful next to customer value. The standard companion metric is LTV (customer lifetime value) — the total revenue a customer generates before churning. If a hosting subscriber pays 10 EUR a month and stays three years, an 80 EUR CAC is excellent; the same CAC for a customer who churns after two months is a loss. Payback period — how many months of revenue it takes to recover CAC — completes the picture.

Practical use cases

Businesses use CAC to:

• Compare channels — paid search, social ads, content marketing, referrals and partnerships rarely acquire customers at the same cost or quality;
• Set bidding limits — a target CPA in ad platforms is usually derived from an acceptable CAC;
• Judge unit economics — investors read LTV:CAC and payback as the health check of a growth engine;
• Prioritise retention — when CAC rises, improving conversion rates and reducing churn is often cheaper than buying more traffic.

Typical levers for lowering CAC include landing page and funnel optimisation, sharper audience targeting, growing organic channels such as SEO, referral programmes, and segment-level measurement — a blended, company-wide CAC can hide segments where acquiring a customer costs more than they will ever pay.