How many euros of new revenue does each euro you spend on sales and marketing bring you? The SaaS Magic Number answers with a single number: it measures how efficiently your commercial machine turns spend into growth. It is one of the most used metrics by investors and funds to decide whether a SaaS company can scale marketing safely. This calculator determines it, together with the gross-margin version, the quarterly growth and the implied CAC payback — the numbers that tell you whether to press the accelerator or optimize first.

What the SaaS Magic Number is

The Magic Number measures how many euros of new annual recurring revenue each euro spent on sales and marketing generates. It is calculated by dividing the new quarterly revenue, annualized, by the prior quarter's sales and marketing spend. A Magic Number of 1 means every euro invested in S&M produces one euro of new recurring per year: the cost is recovered in about a year. The higher the value, the more efficient the growth; a low value signals that acquiring customers costs too much.

What it measures: sales and marketing efficiency

Unlike metrics that look at growth or profitability, the Magic Number looks at acquisition efficiency: the ratio between what you spend to grow and what you get. It is fundamental because a SaaS's growth depends on how much it can invest in sales and marketing without destroying value. If every euro spent generates many of new revenue, it makes sense to invest more and scale; if it generates few, scaling would amplify the inefficiency. The Magic Number indicates which of the two scenarios you are in.

The formula and the spend lag

The formula is: new quarterly revenue (current revenue minus prior) multiplied by four to annualize it, divided by the S&M spend. A crucial detail: you use the prior quarter's spend, not the current. The reason is the lag between investment and result: marketing spent today generates revenue in the following months. Relating the new revenue to the spend that actually produced it — the prior quarter's — makes the measure correct and comparable.

The standard thresholds

The Magic Number is read with established thresholds. Under 0.5: the commercial machine is inefficient, better to rethink the go-to-market before investing more. Between 0.5 and 0.75: caution, there is room for optimization. Between 0.75 and 1.0: good, it makes sense to keep investing. Over 1.0: excellent, you can invest aggressively to accelerate growth. These thresholds guide the most important decision for a SaaS: how much to push on acquisition spend.

How the calculator works

Enter the current and prior quarter revenue, the prior quarter's sales and marketing spend and the gross margin. The calculator determines the annualized new revenue, the Magic Number, its gross-margin version, the quarterly growth and the implied CAC payback. The verdict places the Magic Number relative to the standard thresholds, telling you whether to scale aggressively, keep investing, optimize or rethink the strategy.

The values you need

The current and prior quarter revenue are the turnover of two consecutive quarters: their difference is the new revenue generated. The prior quarter's S&M spend is how much you invested in sales and marketing in the quarter before (because of the lag). The gross margin is used for the more conservative version of the Magic Number and for the CAC payback. Use consistent quarterly data for a correct result.

The annualized new revenue

The annualized new revenue is the first result: the difference between the two quarters' revenue, multiplied by four. It represents the annual recurring revenue added, the one the marketing spend produced. If you go from €1,000,000 to €1,100,000 of quarterly revenue, you added €100,000 per quarter, that is €400,000 on an annual basis. It is the numerator of the Magic Number: what you get, to be compared with what you spent to get it.

The Magic Number (result)

The Magic Number is the key ratio: annualized new revenue divided by S&M spend. A value of 1.0 indicates solid efficiency; above 1.0 acquisition is very efficient and scaling makes sense; below 0.5 it is inefficient. It is the number investors look at first when assessing whether a SaaS can grow by investing: a high Magic Number is the green signal to press the accelerator, a low one an invitation to stop and optimize first.

The gross-margin version

The gross-margin Magic Number multiplies the new revenue by the gross margin before dividing it by the spend. It is stricter, because not all revenue translates into profit: part covers the service delivery costs. With an 80% margin, every euro of revenue is worth only €0.80 of margin, so the "true" Magic Number is lower. This version brings the metric closer to the real economic value of acquisition, and is particularly useful for SaaS with not very high margins.

The implied CAC payback

The implied CAC payback estimates in how many months you recover the acquisition spend through the gross margin of the new recurring revenue. It is closely linked to the Magic Number: a high Magic Number corresponds to a short payback, a low one to a long payback. A payback of 12-18 months is considered healthy for many SaaS; over 24 months signals costly acquisition. The calculator derives it from the entered data, giving you a second lens on commercial efficiency.

The Magic Number thresholds

How to interpret the Magic Number:

The 1.0 threshold separates good efficiency from excellent: above it, every euro invested returns a lot.

Magic Number vs other SaaS metrics

Each SaaS metric measures a different dimension:

They are complementary: the Magic Number should be read together with these for a complete picture of the SaaS's health.

Magic Number and CAC payback

The relationship between the two efficiency measures:

The higher the Magic Number, the faster you recover the acquisition cost: the two metrics tell the same story.

How to improve the Magic Number

To raise the Magic Number you can act on the numerator or the denominator. On the new revenue: improve conversion, reduce churn (net growth rises), expand existing customers, raise prices. On the spend: make acquisition more efficient, focus on the best-returning channels, reduce cost per lead. The most powerful lever is often retention: retaining revenue costs less than acquiring new and directly improves the net new revenue on which the Magic Number is calculated.

The limits of the metric

The Magic Number is powerful but has limits. It does not distinguish between revenue from new customers and expansion revenue from existing ones, which have different acquisition costs. It is sensitive to seasonality: a weak or strong quarter distorts the result. It assumes the new revenue is recurring, but part could be one-off. And the lag between spend and revenue is not always exactly one quarter. It should be read over several quarters and together with other metrics, not as the only criterion.

Common mistakes

• Using the current quarter's S&M spend instead of the prior one.
• Forgetting to annualize the new revenue (multiply by four).
• Assessing a single, maybe seasonal, quarter instead of an average.
• Confusing expansion revenue with new-customer revenue.
• Scaling marketing with a low Magic Number, amplifying the inefficiency.

How to use the calculator

Enter the two quarters' revenue, the prior quarter's S&M spend and the gross margin. Read the annualized new revenue, the Magic Number in both versions, the growth and the CAC payback. Compare the Magic Number with the thresholds to decide whether to scale or optimize. Try different spend levels to see how the efficiency changes. It is the quickest way to assess whether your commercial machine is ready to invest more, with the right numbers.

Practical example

Your revenue goes from €1,000,000 to €1,100,000 between two quarters, and in the prior quarter you spent €400,000 on sales and marketing, with a 75% gross margin. The result: an annualized new revenue of €400,000, a Magic Number of 1.0, a gross-margin Magic Number of 0.75, a quarterly growth of 10% and an implied CAC payback of 16 months, with the verdict "excellent: invest aggressively, every euro in S&M returns a lot". With a Magic Number of 1.0, your acquisition is efficient and you can scale. Enter your numbers for your real situation. The calculation uses annualized quarterly revenue and the prior quarter's S&M spend; it does not distinguish new from expansion, ignores seasonality and churn; the CAC payback is an implied estimate. It is an informational estimate.

Frequently asked questions

What is the SaaS Magic Number?

It is a sales and marketing efficiency metric: it measures how many euros of new annual recurring revenue each euro spent on sales and marketing generates. A value of 1 means every euro spent produces one of new recurring.

How is the Magic Number calculated?

You multiply by four the difference between the current and prior quarter revenue (to annualize it), and divide by the prior quarter's sales and marketing spend. With +€100,000 per quarter and €400,000 of spend, the Magic Number is 1.0.

Why use the prior quarter's spend?

Because of the lag between investment and result: marketing spent today generates revenue in the following months. Relating the new revenue to the spend that produced it — the prior quarter's — makes the measure correct.

What is a good Magic Number?

Under 0.5 is inefficient; between 0.5 and 0.75 to optimize; between 0.75 and 1.0 good; over 1.0 excellent, scaling aggressively makes sense. The 1.0 threshold separates good efficiency from excellent.

What does a high Magic Number mean?

That your commercial machine is very efficient: every euro spent on sales and marketing generates a lot of new revenue. It is the green signal to invest more and accelerate growth, because acquisition returns.

What is the gross-margin Magic Number?

It is a stricter version: it multiplies the new revenue by the gross margin before dividing it by the spend. It accounts for the fact that not all revenue is profit, because part covers the service delivery costs.

What is the relationship with CAC payback?

They are two lenses on the same efficiency: a high Magic Number corresponds to a short CAC payback, a low one to a long payback. A payback of 12-18 months is healthy; over 24 months signals costly acquisition.

Should I annualize the new revenue?

Yes. The formula multiplies by four the difference between the quarterly revenues, to get the new revenue on an annual basis. Forgetting to annualize is a common mistake that gives a Magic Number four times lower.

Does the Magic Number distinguish new from expansion?

No. It combines revenue from new customers and expansion from existing ones, which have very different acquisition costs (expanding costs less). It is a limit to keep in mind in the interpretation.

How do you improve the Magic Number?

By increasing the new revenue (more conversion, less churn, expansion, higher prices) or reducing the acquisition spend (more efficient channels, less cost per lead). Retention is often the most powerful lever.

Is the Magic Number enough to value a SaaS?

No. It measures only sales and marketing efficiency. It should be read together with other metrics — net revenue retention, Rule of 40, Burn Multiple — for a complete picture of the company's health and scalability.

Does it work for any country and currency?

Yes, the Magic Number is an international metric and the calculation is currency-independent: it is a ratio between revenue and spend in the same currency. The 0.5/0.75/1.0 thresholds apply everywhere.

Updated July 2026