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Business & eCommerceGenerated accuracy model review: 2026-05-06
SaaS MRR 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
- Base MRR = customers * ARPA. Net new MRR = new + expansion - contraction - churned. Ending MRR = base MRR + net new MRR.
Test cases
Default input regression check
Generated from the checked-in default inputs and calculate function.
Inputs
- Customers: 500
- ARPA: 49 $/mo
- New MRR: $6,000
- Expansion MRR: $2,000
- Contraction MRR: $1,000
- Churned MRR: $3,000
Expected outputs
- Ending MRR: $28,500.00
- ARR: $342,000.00
- Base MRR: $24,500.00
- Net New MRR: $4,000.00
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
- Rates are user-entered planning assumptions.
- The estimate does not replace accounting, tax, payroll, legal, or marketplace-specific guidance.
- Inputs are processed locally in the browser.
Unit handling
- Customers accepts numeric values.
- ARPA accepts values in $/mo.
- New MRR accepts values in $.
- Expansion MRR accepts values in $.
- Contraction MRR accepts values in $.
- Churned MRR accepts values in $.
- Ending MRR is displayed as currency.
- ARR is displayed as currency.
- Base MRR is displayed as currency.
- Net New MRR 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.
- Input precision follows configured step values where provided.
Version history
1.0.0 - 2026-05-06
Generated accuracy and testing page from the current saas-mrr-calculator calculator definition.
Change log
2026-05-06
Published default regression test documentation and metadata fallbacks for SaaS MRR Calculator.
Calculator transparency
Accuracy pages are generated from checked-in calculator definitions and can be upgraded with curated review metadata over time.