CPM stands for Cost per Mille and means the cost per 1,000 ad impressions. It is a standard pricing model in online advertising, especially for display, video, and social campaigns.

How do you calculate CPM?

The CPM formula is: CPM = (Total Cost ÷ Impressions) × 1000. For example, if you spend $500 and receive 200,000 impressions, your CPM is (500 ÷ 200,000) × 1000 = $2.50.

How do I calculate impressions from CPM and budget?

To find impressions when you know CPM and total cost, use: Impressions = (Total Cost ÷ CPM) × 1000. For example, with a $5 CPM and a $1,000 budget, you expect (1000 ÷ 5) × 1000 = 200,000 impressions.

A good CPM depends on your industry, geography, and channel. On many display networks, CPMs between $2 and $10 are common, while highly targeted audiences or premium inventory can be much higher. Instead of chasing the lowest CPM, focus on cost per result (CPA/ROAS).

eCPM means effective CPM. It converts any revenue or cost model (CPC, CPA, etc.) into an equivalent cost per 1,000 impressions: eCPM = (Revenue or Cost ÷ Impressions) × 1000. It is often used by publishers to compare monetization performance across channels.

CPM Calculator – Cost per 1,000 Impressions

Quickly calculate CPM, total cost, impressions, and effective CPM (eCPM) for any ad campaign. Ideal for media buyers, marketers, and publishers.

Total cost / spend

Impressions

Enter the number of ad impressions (views). Use whole numbers only.

Optional: clicks, conversions & revenue (for CPC/CPA & ROI)

Clicks

Conversions

Revenue

How to use the CPM calculator

This CPM (Cost per Mille) calculator lets you work in any direction:

Find CPM – given total cost and impressions.
Find total cost – given CPM and impressions.
Find impressions – given CPM and budget.
Effective CPM (eCPM) – given revenue and impressions.

Optionally, you can add clicks, conversions, and revenue to see CPC, CTR, CPA, ROAS, and eCPM all in one place.

CPM formula

CPM (Cost per 1,000 impressions)

Let:

C = total cost (budget or spend)
I = total impressions

Then:

\[ \text{CPM} = \frac{C}{I} \times 1000 \]

Rearranged formulas

1. Find total cost from CPM and impressions

\[ C = \frac{\text{CPM} \times I}{1000} \]

2. Find impressions from CPM and cost

\[ I = \frac{C}{\text{CPM}} \times 1000 \]

3. Effective CPM (eCPM) – using revenue instead of cost:

\[ \text{eCPM} = \frac{\text{Revenue}}{I} \times 1000 \]

Example calculations

Example 1 – Calculate CPM

You spent $500 and received 200,000 impressions.

\[ \text{CPM} = \frac{500}{200{,}000} \times 1000 = 2.50 \]

Your CPM is $2.50.

Example 2 – How many impressions can I buy?

You have a budget of $1,200 and a target CPM of $6.

\[ I = \frac{1200}{6} \times 1000 = 200{,}000 \]

You can expect about 200,000 impressions.

Example 3 – Compare campaigns with eCPM

Campaign A generated $3,000 from 500,000 impressions:

\[ \text{eCPM}_A = \frac{3000}{500{,}000} \times 1000 = 6 \]

Campaign B generated $2,000 from 200,000 impressions:

\[ \text{eCPM}_B = \frac{2000}{200{,}000} \times 1000 = 10 \]

Even if B has fewer impressions, its eCPM is higher, meaning it earns more per 1,000 impressions.

CPM vs CPC vs CPA

CPM – you pay per 1,000 impressions (good for reach & awareness).
CPC – you pay per click (good for traffic).
CPA – you pay per conversion/action (good for performance).

Use this calculator to convert between them:

CPC = Cost ÷ Clicks
CPA = Cost ÷ Conversions
CTR = Clicks ÷ Impressions
ROAS = Revenue ÷ Cost

What is a good CPM?

There is no universal “good” CPM. It depends on:

Channel (display, video, social, search, programmatic)
Audience targeting (broad vs. highly specific)
Country and device mix
Seasonality and competition

Instead of chasing the lowest CPM, focus on cost per result (CPA) and return on ad spend (ROAS). A higher CPM can still be better if it drives more valuable conversions.

Tips for using CPM in planning

Use historical CPMs from your accounts as a starting point.
Always add a buffer for seasonality and auction volatility.
Compare publishers or platforms using eCPM and CPA, not CPM alone.
For brand campaigns, track reach and frequency alongside CPM.

CPM Calculator FAQ

Use this formula:
CPM = (Total Cost ÷ Impressions) × 1000.
Example: $800 spend and 400,000 impressions gives CPM = (800 ÷ 400,000) × 1000 = $2.00.

CPM is usually the price you pay per 1,000 impressions. eCPM (effective CPM) converts any revenue or cost model into an equivalent CPM using the formula: eCPM = (Revenue or Cost ÷ Impressions) × 1000. Publishers use eCPM to compare how well different demand sources monetize their inventory.