every founder has heard of burn multiple. fewer can define magic number. the ones raising series B can usually quote both, in that order, without prompting.
burn multiple judges the whole company. magic number judges one thing — the sales engine. when a partner at Sequoia asks "why aren't you spending more?", they're not being polite. they're telling you your magic number is loud enough that they did the math before the meeting.
most founders hear that question and add headcount. the better ones hear it and check the ratio first.
what magic number actually is
magic number = net new arr added this quarter ÷ s&m spend in the prior quarter.
the lag matters. sales hires don't generate pipeline the week they start. you spend the money in q1, you measure the bookings in q2, and the ratio tells you whether the s&m engine is paying back. it's a one-quarter test of one thing — does another dollar of sales spend turn into more than a dollar of recurring revenue?
both companies burn the same dollar. both have the same burn multiple. the investor will tell company a to spend more and company b to hold the line. burn multiple is identical and irrelevant to the conversation.
the canonical reading, which has held since scale venture partners coined it in 2009:
- over 1.0: the engine is humming. spend more, immediately. this is the moment to hire.
- 0.5 – 1.0: caution. the funnel works but it's not throwing off enough to justify scaling spend.
- under 0.5: stop. the next AE you hire will not pay back. fix conversion, win rates, or pricing before you add headcount.
why burn multiple isn't enough
burn multiple sums up everything — engineering payroll, the office lease, the AWS bill, the s&m spend, the new head of marketing's salary, all of it. it's a verdict on the whole company.
that's useful. it's also blunt. a company can have a clean 1.8x burn multiple because engineering is small and the founders are still selling, and it can still have a broken s&m engine that nobody has stress-tested yet. the day they hire two AEs, the burn multiple drifts to 2.6x and they don't know whether sales was always broken or the hires haven't ramped yet.
magic number isolates the question. it strips out r&d, g&a, and the office, and asks: of the dollars you spent specifically to acquire revenue, how many came back as arr?
that's the question an investor cares about when they're deciding whether to back the next round. burn multiple tells them you're a real business. magic number tells them the business scales.
the question that hides inside the number
when a partner asks "why aren't you spending more on sales?", it sounds encouraging. it isn't. it's a test.
if your magic number is 1.2x, the right answer is "we're hiring two AEs next month and lifting the ad budget." the answer they don't want to hear: "we're being disciplined." discipline at a 1.2x magic number is leaving compounding on the table — every dollar of s&m you don't spend is a dollar of arr you didn't add.
if your magic number is 0.4x, the same question is a trap. "we're hiring two AEs next month" tells the investor you can't read your own dashboard. the right answer is "we're working on conversion and pricing first. we'll scale spend when the ratio supports it." that answer wins more rounds than the optimistic one, by a wide margin.
the worst answer to "why aren't you spending more?" is the optimistic one — it tells the investor you can't tell the difference between a working funnel and a broken one.
how founders mis-allocate against this
three patterns repeat.
one. the founder reads a16z's annual saas benchmarks, sees the median magic number is 0.7x, and decides their 0.6x is "in range." median is not the bar. companies clearing series B in 2026 are running 0.9x to 1.3x at the time of the raise. 0.6x is the answer to a different question.
two. the founder confuses pipeline coverage with magic number. pipeline at 4x quota looks great until you measure conversion, and conversion has been quietly cratering for two quarters. magic number catches this because it uses booked arr, not pipeline. pipeline is a story. bookings are a number.
three. the founder includes founder-led deals in s&m efficiency math. those deals had a cac of zero. once you hire the AE, cac goes from zero to whatever the AE plus their tooling plus the BDR plus the marketing attribution costs. magic number quietly collapses and the founder thinks the AE is bad. usually the AE is fine — the founder was just under-counting the prior period.
how zift handles this
zift computes magic number alongside burn multiple, mrr, and runway from your stripe + payroll + ad platform data, every fifteen minutes. on the first of the month you see both numbers, the delta from last quarter, and which s&m line drove the change. you'll know whether to hire the AE before the investor asks.
if you're a finance lead at a series A team running this against a real sales plan with multiple segments or geographies, zift handles that too.
investors look at both numbers. founders who only look at one are guessing about the other.