LTV:CAC Ratio
You're spending to acquire clients. Are you getting it back? The LTV:CAC ratio is lifetime value divided by customer acquisition cost. Rule of thumb: 3:1 means a healthy business—you make $3 of profit over the relationship for every $1 you spend to acquire. Higher ratio = better unit economics. If the ratio is low or negative, you're buying clients at a loss or barely breaking even.
Same spend, different ratio. You spend $2k to acquire a client. If their LTV (profit over the relationship) is $4k, ratio is 2:1—tight. If you improve retention and upsell so LTV is $9k, ratio is 4.5:1—healthy. The ratio tells you if your acquisition and retention strategy work together. CAC and lifetime value are the two levers; KPIs for scaling should include this ratio.
LTV ÷ CAC. Aim for at least 3:1. Improve by raising LTV (retention, upsell) or lowering CAC (referrals, positioning).
How to calculate and use it
Get LTV and CAC. Lifetime value: average profit per client over the relationship. CAC: total acquisition cost (marketing, sales, your time) divided by new clients in that period. Ratio = LTV ÷ CAC. Track it monthly or quarterly so you see trends.
Interpret the ratio. Below 2:1 you're spending too much to acquire or clients don't stay (or don't pay enough). At 3:1 you have room to invest and grow. Above 4:1 or 5:1 you're in strong shape—consider investing more in acquisition (if you have capacity) or improving margin. The ratio is a health check; it doesn't tell you where to act, but it tells you if acquisition and retention are in balance.
Improve by moving the levers. Raise LTV: client retention strategy, upsell, retainer model. Lower CAC: referral marketing, lead qualification, positioning and niche positioning so you attract the right people with less spend.
LTV:CAC ratio calculator
Lifetime value ÷ CAC. Rule of thumb: 3:1 or higher is healthy.
What breaks
Only looking at CAC or only LTV. If you optimize for low CAC but clients leave after one month, your ratio can still be bad. If you optimize for high LTV but you're spending $10k to acquire each client, same problem. The ratio forces you to look at both. KPIs should include LTV:CAC so you don't optimize one lever and break the other.
Not tracking it. If you don't know your ratio, you're flying blind. Simple math: total acquisition spend ÷ new clients = CAC. Average revenue per client × average lifespan × margin = LTV. Approximate is fine; improve the data over time.