How to use it
Choose where to start:
- A budget. Type the amount and see what it buys.
- A conversion goal. Type how many conversions you want and get the budget needed.
Then choose how you pay:
- Per 1,000 impressions (CPM). Display, video, social and most programmatic buying. Enter a CPM and a CTR.
- Per click (CPC). Search and many shopping campaigns. Enter a CPC; the CTR is optional and only used to estimate impressions.
Add a conversion rate to get conversions and cost per conversion, and revenue per conversion to get revenue and ROAS.
The formulas
Paying per 1,000 impressions:
Impressions = budget ÷ CPM × 1,000
Clicks = impressions × CTR
Conversions = clicks × conversion rate
Paying per click:
Clicks = budget ÷ CPC
Conversions = clicks × conversion rate
Then for both:
Cost per conversion = budget ÷ conversions
Revenue = conversions × revenue per conversion
ROAS = revenue ÷ budget
Working back from a goal reverses the chain: clicks needed = conversions ÷ conversion rate, then budget = clicks × CPC, or impressions needed = clicks ÷ CTR and budget = impressions × CPM ÷ 1,000.
Worked examples
What $2,500 buys on CPM. CPM $8.50, CTR 1.2%, conversion rate 3.5%, $65 per conversion.
- Impressions: $2,500 ÷ $8.50 × 1,000 = 294,117.6, about 294,118.
- Clicks: 294,117.6 × 1.2% = 3,529.4, about 3,529. Effective CPC $0.71.
- Conversions: 3,529.4 × 3.5% = 123.5, about 124.
- Cost per conversion: $2,500 ÷ 123.53 = $20.24.
- Revenue: 123.53 × $65 = $8,029.41, so ROAS is 3.21x.
Budget for 50 conversions on CPC. CPC $1.20, conversion rate 4%. Clicks needed: 50 ÷ 4% = 1,250. Budget: 1,250 × $1.20 = $1,500. Cost per conversion $30.
Budget for 50 conversions on CPM. Same rates as the first example. Clicks needed 50 ÷ 3.5% = 1,428.6; impressions needed 1,428.6 ÷ 1.2% = 119,047.6; budget 119,047.6 × $8.50 ÷ 1,000 = $1,011.90.
| Plan | Budget | Clicks | Conversions | Cost per conversion |
|---|---|---|---|---|
| CPM $8.50, CTR 1.2%, CVR 3.5% | $2,500.00 | 3,529 | 124 | $20.24 |
| CPC $1.20, CVR 4% | $1,500.00 | 1,250 | 50 | $30.00 |
| CPC $0.80, CVR 3% | $2,500.00 | 3,125 | 94 | $26.67 |
Where the rates should come from
Use your own past campaigns first: the CPM, CPC, CTR and conversion rate from the same platform, audience and offer. If you have none, run a small test and plan from its results. This page deliberately shows no "typical" rates, because they vary so much by platform, country, season and audience that a generic number would mislead the plan more than it helps.
Plans like this are straight lines. Real campaigns are not: costs often rise as you spend more on the same audience, and conversion rates drift. Treat the output as the shape of the plan and check it against real results after the first week.
Rounding in a chained plan
Each step uses the unrounded result of the step before. The display rounds impressions, clicks and conversions to whole numbers, but the cost per conversion above is $2,500 ÷ 123.53, not $2,500 ÷ 124. That keeps a long chain from drifting. The working shows each step so you can repeat it in a spreadsheet.
How this calculator handles your numbers
Inputs become exact fractions and nothing is rounded until display: money to two decimals, counts to whole numbers, ROAS to two decimals. Rates are percentages: type 1.2 for 1.2%. A CPM or CPC of zero, or a zero CTR or conversion rate when working back from a goal, would mean dividing by zero, so the calculator asks for a value above 0 instead.