Back to calculator
Business & eCommerceGenerated accuracy model review: 2026-05-06
CPM Calculator accuracy and testing
This page documents how Calwarden builds trust for this calculator: source notes, regression-style default tests, limitations, assumptions, unit handling, rounding, and visible change history.
Formula source
- **CPM = (Total Cost / Total Impressions) * 1000.** Example: If you spend $500 and get 50,000 impressions, your CPM is ($500 / 50,000) * 1000 = $10.
Test cases
Default input regression check
Generated from the checked-in default inputs and calculate function.
Inputs
- Total Cost: $500
- Impressions: 50,000
Expected outputs
- CPM: $10.00
- Cost Per Impression: $0.01
Known limitations
- This page documents the checked-in calculator logic and does not certify results for every real-world edge case.
- Use the result as a planning estimate unless the calculator page states a stricter purpose.
Assumptions
- The calculator assumes impression counts are valid and directly comparable across the channels you are reviewing.
- CPM reflects visibility cost only; it does not measure clicks, leads, or downstream revenue.
- If impressions are zero, CPM is undefined rather than free.
Unit handling
- Total Cost accepts values in $.
- Impressions accepts numeric values.
- CPM is displayed as currency.
- Cost Per Impression is displayed as currency.
Rounding rules
- Number displays use up to 2 decimal places in the calculator UI.
- Currency outputs are displayed with standard US dollar formatting.
Version history
1.0.0 - 2026-05-06
Generated accuracy and testing page from the current cpm-calculator calculator definition.
Change log
2026-05-06
Published default regression test documentation and metadata fallbacks for CPM Calculator.
Calculator transparency
Accuracy pages are generated from checked-in calculator definitions and can be upgraded with curated review metadata over time.