Startup · Local-first · Beta

SaaS Metrics Calculator

Build a period-consistent SaaS snapshot covering MRR, ARR, retention, CAC payback and Rule of 40.

Instant result•No account•Inputs stay in your browser

Phase 5 toolkit beta

Enter your assumptions

Runs locally

Measurement period in months

Every metric is interpreted over this declared period.

Current MRR

Monthly recurring revenue at the end of the measurement period.

Prior-period MRR

MRR at the comparable starting point.

New MRR

MRR from new customers during the period; shown for reconciliation.

Expansion MRR

Upsell or expansion MRR from existing customers.

Contraction MRR

Downgrade MRR from existing customers.

Churned MRR

MRR lost from customers who churned.

Current customers

Customers at the end of the period.

Prior-period customers

Customers at the comparable starting point.

New customers

New customers acquired during the period.

Churned customers

Customers lost during the period.

Sales and marketing cost

Cost attributed to the same measurement period for CAC payback.

Gross margin

Gross margin used for contribution and CAC-payback illustrations.

Operating or profit margin

User-entered margin used only in the Rule of 40 illustration.

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Trust record

Check the method before you rely on the result

Tier B · Runs locally in this browser

Method: Definition-led SaaS metric worksheet using one declared measurement period.; ARR = MRR × 12; window growth is annualized over the declared period; monthly churn is normalized from window churn; GRR = (prior MRR − churn − contraction) ÷ prior MRR; NRR adds expansion; CAC payback = CAC ÷ monthly gross-margin contribution.
Sources: 1 reviewed reference; Open the source register
Effective period: Formula-based; no statutory effective period
Last verified: 10 August 2026; Review every 365 days
Reviewer status: Startup metrics reviewer: external review pending
Privacy: Startup inputs and results stay in this browser. They are not sent to analytics, a backend, a URL or a log, and are not saved by default. These outputs are user-entered scenarios, not recommendations or professional valuations.

Important limitations

No accounting recognition, cohort normalization or benchmark ranking is performed.
Rule of 40 uses your user-entered margin and the observed MRR change; it is not a company-quality score.

Read all limitations Report an error

Browse Startup · Methodology · Sources

A quick guide

Use the number with context

The answer is only useful when you know what it includes and what it leaves out.

How to use it

Enter measurement period in months using the same period and unit as the other inputs.
Enter current mrr using the same period and unit as the other inputs.
Enter prior-period mrr using the same period and unit as the other inputs.
Enter new mrr using the same period and unit as the other inputs.
Enter expansion mrr using the same period and unit as the other inputs.
Enter contraction mrr using the same period and unit as the other inputs.
Enter churned mrr using the same period and unit as the other inputs.
Enter current customers using the same period and unit as the other inputs.
Enter prior-period customers using the same period and unit as the other inputs.
Enter new customers using the same period and unit as the other inputs.
Enter churned customers using the same period and unit as the other inputs.
Enter sales and marketing cost using the same period and unit as the other inputs.
Enter gross margin using the same period and unit as the other inputs.
Enter operating or profit margin using the same period and unit as the other inputs.

Formula

ARR = MRR × 12; window growth is annualized over the declared period; monthly churn is normalized from window churn; GRR = (prior MRR − churn − contraction) ÷ prior MRR; NRR adds expansion; CAC payback = CAC ÷ monthly gross-margin contribution.

Metrics are comparable only when revenue, customers, churn and acquisition costs share definitions and periods.

Make it concrete

Worked example

₹5,00,000 MRR becomes ₹60,00,000 ARR; retention and payback metrics use the same period inputs.

Boundaries

What this tool does not assume

Limitations

No accounting recognition, cohort normalization or benchmark ranking is performed.
Rule of 40 uses your user-entered margin and the observed MRR change; it is not a company-quality score.

Edge cases

Zero new customers omits CAC and payback.
Zero logo churn omits LTV:CAC instead of implying infinite retention.

Last reviewed 10 August 2026 · Formula version 1.0

Method & sources

How this result is grounded

The formula is deterministic and runs in your browser. Read the reference below for the method used by this tool.

Startup and SaaS metrics methodology v1
KarobarKit controlled methodology · authoritative reference · Checked 10 August 2026
Supports: startup metrics definitions · scenario boundaries · period consistency

Questions

Frequently asked

What is NRR?

NRR measures starting recurring revenue after churn, contraction and expansion, excluding new customer revenue.

Does the tool benchmark my startup?

No. It calculates only the definitions and assumptions you enter.

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Source register checked 10 August 2026.