You're flying blind without these numbers
Every SaaS founder knows that vanity metrics like total signups or new users don't tell the real story. What matters is whether your paying customers are actually sticking around and generating predictable revenue. Miss the signals hidden in MRR, ARR, churn, and LTV, and you'll wake up one quarter to find your growth stalling or your unit economics broken. This calculator puts the five metrics that matter most right at your fingertips.
What This Calculator Does
This tool computes the essential health indicators for any subscription business: Monthly Recurring Revenue (MRR), Annual Recurring Revenue (ARR), customer churn rate, Customer Lifetime Value (LTV), Customer Acquisition Cost (CAC), and the LTV:CAC ratio that investors and operators watch obsessively. Feed it your current paying customers, average monthly revenue per customer, lost customers over a period, and your total acquisition spend-and instantly see whether your business model is sustainable, which cohorts are your best customers, and whether you're spending too much to acquire them.
How to Use This Calculator
Step 1: Count your paying customers right now. If you have 200 active subscriptions, enter 200.
Step 2: Divide your total monthly recurring revenue by the number of paying customers to get your Average Revenue Per User (ARPU). If you brought in $50,000 last month from 200 customers, your ARPU is $250.
Step 3: Enter how many customers you lost last month or last quarter. If 5 customers churned out of 200, that's a 2.5% monthly churn rate. Be honest here-every churn dollar signals a problem you need to fix.
Step 4: Add up all your Sales and Marketing spend for the period. This includes your salaries if you're doing the sales yourself, ad spend, tools, and commissions. If you spent $15,000 on customer acquisition and acquired 50 new customers, your CAC is $300.
Step 5: Hit calculate and read the story: Your MRR, ARR, and the ratio of lifetime value to acquisition cost. A 3:1 ratio is the benchmark healthy SaaS businesses target. Below 3:1 and you're spending too much to acquire customers. Above 5:1 and you're killing it.
The Formula Behind the Math
MRR (Monthly Recurring Revenue)
MRR = Number of Paying Customers × ARPU
Example: 200 customers × $250/month = $50,000 MRR.
ARR (Annual Recurring Revenue)
ARR = MRR × 12
Example: $50,000 × 12 = $600,000 ARR.
Churn Rate (Monthly)
Monthly Churn Rate = (Lost Customers / Starting Customers) × 100
Example: 5 lost customers / 200 starting customers = 2.5% churn.
Customer Lifetime Value (LTV)
LTV = ARPU / Monthly Churn Rate
Example: $250 / 0.025 = $10,000 LTV. This customer will generate $10,000 in total revenue over their lifetime (assuming consistent metrics).
Customer Acquisition Cost (CAC)
CAC = Total Sales & Marketing Spend / Number of New Customers Acquired
Example: $15,000 S&M spend / 50 new customers = $300 CAC.
LTV:CAC Ratio
LTV:CAC = LTV / CAC
Example: $10,000 / $300 = 33:1 ratio (you're printing money). A healthy ratio is 3:1 or higher.
Our calculator does all of this instantly-but now you understand exactly what it's computing.
SaaS Founders Tracking Unit Economics
You're at $30K MRR but burn is climbing and you can't figure out why. When you plug your numbers into this calculator, you discover your CAC jumped from $250 to $450 while your churn ticked up to 6%. Your LTV:CAC ratio dropped to 2.2:1. The message is clear: your acquisition strategy is getting expensive, and your retention needs immediate attention. This insight-visible instantly in one place-lets you decide whether to cut marketing spend, focus on onboarding, or fix your product.
Sales Leaders Evaluating Growth Efficiency
Your CEO asks: "Are we efficient at growth?" You could spend a week building a spreadsheet, or you could enter your current metrics into this calculator and have a clear answer in 30 seconds. A 4:1 LTV:CAC ratio signals you can safely scale. A 2:1 ratio says "pump the brakes on customer acquisition." This becomes the conversation starter with leadership and the benchmark for your sales team.
Venture-Backed Teams Reporting to Investors
Investors want SaaS metrics. Period. They scan for MRR growth, CAC payback period (how many months to recoup acquisition spend), and churn. This calculator gives you the crisp numbers to drop into pitch decks and quarterly reports. When you show an LTV of $8,000, a CAC of $1,200, and a 6:1 ratio, you're speaking the language that gets funding.
Operators Comparing Across Cohorts
You suspect your 2024 cohort is higher quality than 2023. Run each cohort's numbers separately through this calculator and compare. Different ARPU? Different churn? Different LTV? Now you can decide: invest more in the 2024 motion and dial back 2023. Data-driven pivots beat gut feelings.
Tips and Things to Watch Out For
ARPU can hide problems. If you average together a $50/month customer with a $500/month enterprise customer, you get a middle number that misleads. Try to segment your metrics by customer tier or cohort so you see the real story.
Churn is the silent killer. Even 3% monthly churn compounds into catastrophe. A customer lost today is gone; her LTV calculation becomes zero. If your churn is higher than 5%, retention is your most urgent problem, not acquisition.
Don't confuse gross and net churn. Gross churn is customer churn; net churn includes both churn and expansion (upsells). Many healthy SaaS businesses have negative net churn because expansion revenue outweighs churn. This calculator tracks gross churn, which is fine for the basics.
CAC should account for all acquisition costs. Your salesperson's salary, customer success onboarding, free trial hosting, support tickets during evaluation-it all counts. Underestimating CAC paints a rosier picture and leads to bad decisions.
Benchmark against your industry. SaaS CAC and LTV vary wildly. PLG (product-led growth) businesses might have a $50 CAC and $2,000 LTV. Enterprise sales might have a $15,000 CAC and $200,000 LTV. Know your peer benchmarks so you don't over-optimize for the wrong thing.
This calculator uses steady-state metrics. Real businesses have seasonality, cohort effects, and growth curves. Use this as a snapshot and a conversation starter, not as gospel truth. Pair it with weekly trend tracking to catch inflection points early.
*This calculator provides estimates based on the metrics you input. Actual results depend on your specific business model, customer segments, and market conditions. Consult with a financial advisor if you're making major strategic decisions based on these numbers.*
Frequently Asked Questions
What's a good LTV:CAC ratio?
A 3:1 ratio is the widely accepted minimum for healthy SaaS. You're earning three dollars in lifetime value for every dollar spent acquiring the customer. 5:1 or higher is strong; under 2:1 suggests your acquisition is too expensive or retention needs work.
How often should I recalculate these metrics?
Monthly. SaaS metrics change fast. A good practice is to run this calculator on the last day of each month using your actual numbers, then compare month-over-month to spot trends (rising churn, shrinking ARPU, CAC inflation).
Should I include annual customers in my MRR calculation?
Yes. Convert annual subscriptions to their monthly equivalent (divide annual price by 12) so you're adding apples to apples. Some founders calculate MRR and ARR separately to see contractual revenue, but for unit economics, the monthly view matters most.
Why does churn matter more than acquisition at scale?
Because churn compounds. If you grow MRR 10% month-over-month but lose 5% to churn, you're only really growing 5%. At scale, a 1% difference in churn can be worth millions in lifetime value. Save money, retain better.
How do I reduce my CAC?
Nail referrals (lower cost per customer), improve your product so it sells itself (product-led growth), and optimize your sales funnel (conversion rate improvements = fewer touches per deal = lower CAC). This calculator will show you which levers move the needle.
Is a high LTV enough if CAC is also high?
Not necessarily. A $100,000 CAC is fine if your LTV is $500,000, but it's terrible if it's $150,000. What matters is the ratio and the payback period (how many months until that customer's revenue covers their acquisition cost). Aim for sub-12-month payback.
What if my ARPU varies by customer?
Segment your customers. Run the calculator separately for enterprise, mid-market, and self-serve. You'll find that one segment has a great LTV:CAC ratio and another is a black hole. This insight guides where to focus your sales effort.
Related Calculators
Once you've got your SaaS metrics dialed in, dig deeper with the CAC/LTV calculator to stress-test different acquisition and retention scenarios. Use the runway calculator to forecast how long your cash lasts given your current burn. Check the pricing calculator to see if you're leaving money on the table with your current rate card.