Growth

SaaS Metrics 101: The Numbers Every Founder Should Track

A beginner-friendly guide to essential SaaS metrics including MRR, ARR, churn, LTV, CAC, and more.

January 8, 2026HackerBadges Team

SaaS Metrics 101: The Numbers Every Founder Should Track

If you're building a subscription business, metrics are your map. Without them, you're flying blind.

Here's every metric you need to understand, calculate, and optimize.

The Big 3: Revenue Metrics

MRR (Monthly Recurring Revenue)

What it is: The total predictable revenue you get each month from subscriptions.

How to calculate:

MRR = (Number of customers) × (Average revenue per customer)

Example: 50 customers × $20/month = $1,000 MRR

Why it matters: MRR is the heartbeat of any SaaS. It tells you exactly how much revenue you can expect next month.

ARR (Annual Recurring Revenue)

What it is: MRR multiplied by 12. Your annualized revenue.

How to calculate:

ARR = MRR × 12

Example: $1,000 MRR × 12 = $12,000 ARR

Why it matters: ARR is used for valuation, fundraising, and planning. VCs think in ARR.

Revenue Growth Rate

What it is: How fast your revenue is growing month-over-month.

How to calculate:

Growth Rate = ((This month MRR - Last month MRR) / Last month MRR) × 100

Example: ($1,100 - $1,000) / $1,000 × 100 = 10% growth

Benchmarks:

  • Early stage: 15-20% month-over-month is great
  • Growth stage: 5-10% month-over-month is solid
  • Mature: 2-5% month-over-month is healthy

Customer Metrics

Churn Rate

What it is: The percentage of customers who cancel each month.

How to calculate:

Churn Rate = (Customers lost this month / Customers at start of month) × 100

Example: 5 customers churned / 100 customers = 5% monthly churn

Why it matters: Churn is the silent killer. A 5% monthly churn means you lose 46% of your customers yearly.

Benchmarks:

  • <2% monthly churn: Excellent
  • 2-5% monthly churn: Average
  • 5% monthly churn: Problem

Net Revenue Retention (NRR)

What it is: How much revenue you retain from existing customers, including upgrades and downgrades.

How to calculate:

NRR = ((Starting MRR + Expansion - Churn - Contraction) / Starting MRR) × 100

Example: ($10,000 + $500 - $300 - $200) / $10,000 = 100% NRR

Why it matters: NRR over 100% means you're growing without acquiring any new customers.

Benchmarks:

  • <80%: Serious churn problem
  • 80-100%: Typical
  • 100%: Excellent

  • 120%: World-class (Slack, Twilio)

Customer Count

What it is: How many paying customers you have.

Why it matters: More customers = more stability. One big customer churning hurts less when you have 100 others.

Unit Economics

LTV (Lifetime Value)

What it is: How much revenue a customer generates before they churn.

How to calculate:

LTV = ARPU / Monthly Churn Rate

Example: $50 ARPU / 5% churn = $1,000 LTV

Why it matters: This tells you how much you can afford to spend acquiring a customer.

CAC (Customer Acquisition Cost)

What it is: How much it costs to acquire one customer.

How to calculate:

CAC = Total sales and marketing spend / Number of new customers acquired

Example: $5,000 spent / 50 new customers = $100 CAC

Why it matters: If CAC > LTV, you're losing money on every customer. That's bad.

LTV:CAC Ratio

What it is: The ratio between lifetime value and acquisition cost.

How to calculate:

LTV:CAC = LTV / CAC

Benchmarks:

  • <1:1: Losing money on every customer
  • 1-3:1: Break-even to marginally profitable
  • 3:1: Healthy
  • 5:1: Very efficient (or underspending on growth)

Payback Period

What it is: How many months it takes to recover CAC.

How to calculate:

Payback Period = CAC / ARPU

Example: $100 CAC / $20 ARPU = 5 months

Why it matters: Shorter payback = faster cash recovery = faster growth.

Benchmarks:

  • <3 months: Excellent
  • 3-12 months: Good
  • 12 months: Slow, might need improvement

Growth Metrics

New MRR

What it is: Revenue from new customers this month.

Expansion MRR

What it is: Additional revenue from existing customers (upgrades).

Contraction MRR

What it is: Revenue lost from downgrades.

Churned MRR

What it is: Revenue lost from cancellations.

Net New MRR

What it is: The complete picture of growth.

How to calculate:

Net New MRR = New MRR + Expansion MRR - Contraction MRR - Churned MRR

The Metrics Dashboard

Here's what to track at each stage:

Pre-Launch

  • Waitlist signups
  • Conversion rate (signup → waitlist)

Early Stage ($0-$1K MRR)

  • MRR
  • Customer count
  • Churn rate

Growth Stage ($1K-$10K MRR)

  • All of the above, plus:
  • LTV
  • CAC (if you're doing paid acquisition)
  • Net Revenue Retention

Scale Stage ($10K+ MRR)

  • All of the above, plus:
  • LTV:CAC ratio
  • Payback period
  • Expansion MRR

Celebrating Metrics Milestones

Every metric milestone is worth acknowledging:

Revenue Milestones

  • First dollar
  • $100, $500, $1K, $2.5K, $5K, $10K MRR
  • 100% NRR

Customer Milestones

  • First customer
  • 10, 50, 100, 500, 1000 customers

Growth Milestones

  • First month with positive Net New MRR
  • First month with expansion revenue
  • Achieving <2% churn

Create a HackerBadges badge for each one. Make progress visible.

Common Mistakes

1. Vanity Metrics

Problem: Tracking metrics that look good but don't matter (total signups, page views).

Solution: Focus on revenue and retention metrics.

2. Not Tracking Churn

Problem: Only focusing on acquisition.

Solution: Track churn religiously. It's usually more important than acquisition.

3. Ignoring Unit Economics

Problem: Growing at any cost.

Solution: Make sure LTV > CAC before scaling.

4. Comparing to Irrelevant Benchmarks

Problem: Comparing your indie product to venture-backed companies.

Solution: Compare to stage-appropriate peers.

Start Simple

If this feels overwhelming, start with just three metrics:

  1. MRR - Are you making money?
  2. Customer Count - Do people want this?
  3. Churn Rate - Are they staying?

Everything else can wait until you're growing.


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