It is the cleanest read on go-to-market efficiency in a single figure. A magic number of 1.0 means every dollar of sales and marketing brought back a dollar of new ARR within the year. Above 0.75 you can spend more with confidence. Under 0.5 the engine is leaking and adding budget just burns faster.
The free SaaS magic number calculator works it out and shows which efficiency zone you land in.
Above 0.75 is the common benchmark for efficient growth and 1.0 or higher is strong. In that range, spending more on sales and marketing is justified because the spend pays back inside a year. Below 0.75 the model is shaky and below 0.5 you are paying far too much for each dollar of new ARR.
A very high magic number is not a trophy. Above 1.5 usually means you are underinvesting in growth and could safely spend more to capture market while it is open. The goal is an efficient number with the budget cranked as high as it stays efficient, not the highest possible figure.
Faster deals convert spend to ARR inside the measurement window. Tightening the sales process lifts the number without cutting budget.
Channels that do not convert drag the number down. Reallocating from weak channels to proven ones raises efficiency directly.
Expansion revenue costs almost nothing to win, so it improves the magic number on the ARR side. High net revenue retention quietly lifts the figure.
It is a measure of how efficiently your sales and marketing spend turns into new recurring revenue. A magic number of 1.0 means a dollar of GTM spend produced a dollar of new ARR within a year. Above 0.75 you are efficient enough to keep spending, below it you are paying too much to grow.
Take net new ARR added in a quarter, multiply by 4 to annualise it, then divide by the previous quarter sales and marketing spend. The one-quarter lag matters because spend rarely converts to revenue in the same period. The result tells you how many dollars of new ARR each GTM dollar bought.
Above 0.75 is the usual benchmark and 1.0 or higher is strong. In that range it pays to spend more on growth because the spend returns inside a year. Below 0.75 the economics are weak and below 0.5 you are burning money for every dollar of new ARR, so the funnel needs work before the budget does.
Because it usually means you are underspending. A magic number above 1.5 says you could pour far more into growth and still be efficient, so a slower-but-safer stance is leaving market share on the table. The aim is to push spend as high as it stays above the efficiency line, not to maximise the ratio.
CAC measures the cost to win one customer, while the magic number measures the efficiency of total GTM spend against total new ARR. CAC is a per-customer view and the magic number is a whole-engine view. They tell the same story from different heights and a rising CAC usually shows up as a falling magic number.
If your magic number is under the line, the fix is funnel efficiency, not more budget. Book a 30-minute audit and we will find where GTM leaks. No sales sequence.
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