SaaS Churn And LTV Forecaster Calculator

📖 Overview

This calculator reveals whether growth is healthy or expensive by combining churn and economics in one view.

It estimates MRR leakage customer lifetime value and CAC payback pressure so founders can prioritize fixes faster.

🧪 Example Scenarios

Use these default and higher-pressure example inputs to explore how sensitive this calculator is before using your real numbers.

Input	Base Case	Higher Pressure Case
Monthly Recurring Revenue MRR ($)	42,000	37,800
Monthly Churn Rate (%)	4.2	5.04
Average Revenue Per User ARPU ($)	78	70.2
Customer Acquisition Cost CAC ($)	320	384
Gross Margin (%)	82	98.4

⚙️ How It Works

Projects SaaS unit economics by combining churn pressure with ARPU CAC and margin assumptions so retention and acquisition risk are visible in one output.

The Formula

LTV ≈ (ARPU × Gross Margin) ÷ Churn Rate | MRR Leak = MRR × Churn Rate

MRR	Current monthly recurring revenue from active customers
Churn Rate	Monthly percentage of revenue/customers lost
ARPU	Average monthly revenue per customer
CAC	Blended customer acquisition cost
Gross Margin	Percent revenue retained after delivery cost

💡Small churn reductions usually create outsized LTV improvement. In many SaaS models retention fixes beat pure top-of-funnel spend.

Quick Reference

Churn	ARPU	Margin	Implied LTV
2%	$80	80%	$3,200
4%	$80	80%	$1,600
6%	$80	80%	$1,067

When To Use This

Use this tool when you need a fast decision during active planning or execution.
Use this before committing money, time, or tradeoffs that are hard to reverse.
Use this to compare options using the same assumptions across scenarios.

Edge Cases To Watch

Results can be misleading if key inputs are missing, stale, or unrealistic.
Very small or very large values may amplify rounding effects and interpretation risk.
If assumptions change mid-decision, recalculate before acting.

Practical Tips

💡 Track net revenue churn separately for expansion and contraction visibility.

💡 Audit CAC by channel because blended CAC can hide weak sources.

💡 Run the same model monthly to detect unit economics drift early.

Frequently Asked Questions

❓ What is a healthy LTV to CAC ratio?

Many SaaS teams target 3.0 or higher but the right threshold depends on growth stage and capital constraints.

❓ Why does high churn hurt so much?

Because customer lifetime shortens quickly which compresses recoverable gross profit per acquired customer.