SaaS Magic Number Calculator
Sales & marketing efficiency.
Calculate the SaaS magic number from quarterly MRR growth and combined sales-and-marketing spend, given current and prior quarter MRR.
What this tool does
The SaaS magic number is a ratio that measures sales and marketing efficiency by comparing quarter-over-quarter monthly recurring revenue growth to the spending that drove it. The calculator takes your current and previous quarter MRR alongside previous quarter sales and marketing spend, then returns an annualised efficiency ratio. A result above 1 indicates that each unit of currency spent on sales and marketing generated more than one unit of MRR growth over the year. The metric relies on the assumption that current spending patterns remain consistent and doesn't account for seasonal variations, customer acquisition costs over time, or revenue retention rates. This calculation is for illustration only and reflects a snapshot of efficiency during a specific quarter.
Enter Values
People also use
SaaS & Subscription
CAC Payback Period Calculator
Calculate CAC payback period in months from customer acquisition cost, MRR per customer, and gross margin on the contract.
SaaS & Subscription
SaaS LTV:CAC Ratio Calculator
Calculate SaaS LTV-to-CAC ratio from MRR, gross margin, monthly churn, and customer acquisition cost, plus the implied payback months.
Marketing & Growth
Cost Per Acquisition Calculator
Calculate cost per acquisition and LTV:CPA ratio for marketing efficiency. Enter marketing spend and new customers to see cpa and ltv:cpa ratio.
Formula Used
Spotted something off?
Calculations or display — let us know.
Disclaimer
Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.
The SaaS Magic Number measures sales and marketing efficiency: how much new ARR each pound of previous-quarter S&M spend generated. Formula: (current MRR - previous MRR) × 12 ÷ previous-quarter S&M spend. Above 0.75 means 'invest more'; 0.5-0.75 means 'invest cautiously'; below 0.5 means 'efficiency problems'.
120k current MRR - 100k previous = 20k incremental MRR, or 240k new ARR. Against 200k of previous-quarter S&M spend, Magic Number = 1.2. Excellent - each 1 of S&M is producing 1.20 of new ARR within one quarter, and the CAC payback compounds over future quarters. Invest more aggressively.
The one-quarter lag matters. S&M spent this quarter drives pipeline and wins next quarter, not this quarter. Measuring current quarter MRR against current quarter spend inflates the number; against previous quarter spend is the standard benchmark. Most public SaaS companies report Magic Number 0.6-1.2 in growth stages; mature SaaS 0.3-0.6.
A worked example
Try the defaults: current quarter mrr of 120,000, previous quarter mrr of 100,000, previous quarter s&m spend of 200,000. The tool returns 1.20. You can adjust any input and the result updates as you type — no submit button, no reload. That's the real power here: seeing how sensitive the output is to one or two assumptions.
What moves the number most
The result responds to Current Quarter MRR, Previous Quarter MRR, and Previous Quarter S&M Spend. Not every input has equal weight. Adjusting one input at a time toward extreme values shows which ones move the result most.
The formula behind this
Magic Number = (MRR growth × 12) ÷ previous quarter S&M spend. Everything the calculator does is shown in the formula box below, so you can check the math against your own spreadsheet if you want.
Using this as a check-in
Re-run this every three months. A single reading tells you where you stand; four readings tell you whether things are improving. The trend matters more than any individual snapshot.
What this doesn't capture
The score is a composite of the inputs you provide. Life context — job security, family obligations, health, housing — doesn't appear in the math but shapes the real picture. Use the number as a prompt, not a verdict.
(££120,000 - ££100,000) × 12 ÷ ££200,000 = 1.20.
Inputs
This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.
Sources & Methodology
Methodology
The calculator computes the Magic Number by measuring sales and marketing efficiency over a one-quarter period. It takes the difference between current-quarter monthly recurring revenue and previous-quarter monthly recurring revenue, multiplies that quarterly growth by 12 to annualize it, then divides the result by the previous quarter's sales and marketing spend. The output represents the revenue generated per unit of sales and marketing investment. The model assumes a linear, constant growth rate and does not account for seasonal variation, time lag between spending and revenue recognition, customer acquisition cost distribution, churn, or changes in pricing. Results reflect historical efficiency only and should not be interpreted as predictive of future performance.
References
Frequently Asked Questions
What's the interpretation?
Why the 1-quarter lag?
Magic Number vs CAC payback?
Does this work for early-stage?
Related Calculators
CAC Payback Period Calculator
Calculate CAC payback period in months from customer acquisition cost, MRR per customer, and gross margin on the contract.
SaaS LTV:CAC Ratio Calculator
Calculate SaaS LTV-to-CAC ratio from MRR, gross margin, monthly churn, and customer acquisition cost, plus the implied payback months.
Cost Per Acquisition Calculator
Calculate cost per acquisition and LTV:CPA ratio for marketing efficiency. Enter marketing spend and new customers to see cpa and ltv:cpa ratio.
More SaaS & Subscription Calculators
SaaS & Subscription
Annual Recurring Revenue Growth Calculator
Calculate your annual recurring revenue growth rate year-over-year and track absolute ARR added — the core SaaS metric investors review first.
SaaS & Subscription
ARPU Calculator
Calculate ARPU by entering total revenue and active user count to see average revenue per user monthly and annualised instantly.
SaaS & Subscription
ARR Calculator
Calculate current ARR and forecast future ARR using your MRR and monthly growth rate over a 12 to 24 month projection horizon.
SaaS & Subscription
ARR Payback Period Calculator
Calculate ARR payback period using total CAC spend, new ARR added, and gross margin to estimate months until acquisition costs are recovered.
SaaS & Subscription
CAC Payback Period Calculator
Calculate CAC payback period in months from customer acquisition cost, MRR per customer, and gross margin on the contract.
SaaS & Subscription
Churn Rate Calculator
Calculate churn rate and net growth rate from starting customers, customers churned, and customers gained during the period.
Explore Other Financial Tools
Money Insights
Money Mistakes Compound Cost Calculator
Calculate the compound cost of past money mistakes. See the combined opportunity cost of up to three financial errors at today's value.
Investing
ETF Expense Ratio Drag Calculator
Calculate ETF expense ratio drag impact on long-term returns — a small percentage compounded over decades costs real wealth.
Psychology & Behavioral
Decision Fatigue Cost Tool
Estimate the financial impact of decision fatigue across spending choices, time management, and the mental-energy budget it quietly consumes.