CPM vs CPC: which is cheaper?
CPM charges per 1,000 impressions; CPC charges per click. CPM is cheaper when your ads get clicked often, and CPC is cheaper when they don't. The dividing line is your click-through rate: break-even CPM = CPC × CTR × 1,000.
Turn a CPM into a cost per click
Effective CPC = CPM ÷ (CTR × 1,000). At a $10 CPM:
| CTR | Effective CPC |
|---|---|
| 0.2% | $5.00 |
| 0.5% | $2.00 |
| 1% | $1.00 |
| 2% | $0.50 |
| 5% | $0.20 |
If you're offered clicks at $1.20 and your CTR is 1%, the $10 CPM buy is cheaper. At a 0.5% CTR, the CPC offer wins.
When to choose each
| Choose CPM when… | Choose CPC when… |
|---|---|
| The goal is reach or awareness, not clicks | The goal is traffic or sales |
| Your creative and targeting are proven, with a high CTR | You're testing new creative or audiences |
| You want predictable delivery and frequency | You want to pay only for engagement |
| You're retargeting a warm audience | You're prospecting a cold audience |
Don't stop at clicks
A cheaper click isn't a cheaper sale. Compare campaigns on cost per conversion (cost ÷ conversions) and ROAS (revenue ÷ cost). The calculator works these out when you add conversions and revenue.
Last reviewed 27 September 2026.