MRR waterfalls, unit economics and scenario layers are all downstream of one assumption: that a customer pays the same amount every month. Usage pricing breaks that assumption, and everything built on top of it.

Chargebee's free SaaS financial model template treats usage as a driver rather than a fixed line — four model layers, an MRR waterfall that handles expansion, contraction and consumption separately, and unit economics that hold up against a variable cost base.

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Hey {{first_name}} 👋, I hope you’re having a great week! In the last issue, we discussed about Due Diligence, and now we are moving with the next topic from Reporting content.

Let’s talk about ⬇️

A founder at $11M ARR showed me a magic number of 1.4.

Exceptional. Top-quartile by any benchmark. He was planning to raise on it.

Then I looked at the sales team. Two AEs. Both at full capacity. Pipeline coverage running at 6x forward quota.

Six times. That's not healthy pipeline. That's demand pooling up behind a bottleneck, waiting for somebody to have time to close it.

The 1.4 wasn't measuring efficiency. It was measuring under-resourcing.

I told him to hire two AEs and a sales engineer, and to expect the number to get worse. It did — dropped to 0.9 as the new hires ramped, then came back to 1.1 as they hit partial productivity.

Absolute new ARR at the end of it: 1.6x the prior baseline.

The metric declined. The business got materially bigger.

For every dollar you spent on sales and marketing last quarter, how much annualized new recurring revenue showed up this quarter?

Magic number = (Current Q ARR − Prior Q ARR) × 4 ÷ Prior Q S&M spend

Prior quarter S&M, not current — there's a lag between putting money into pipeline and that pipeline becoming revenue.

Worked through:

Two input decisions that people get wrong constantly:

Recurring revenue only. No professional services, no implementation fees, no one-time usage. Blend those in and the number looks stronger than it is. Investors will find it, and the conversation gets worse when they do rather than when you disclose it.

Customer success stays out of the denominator — unless your CS team carries an expansion quota. If you exclude it, document that and hold it consistent across every period you report.

The thing most teams miss: this is a net metric. It absorbs churn, contraction, expansion, everything. You can have excellent new-logo CAC and a terrible magic number, because churn is eating the net revenue gain before it reaches the numerator.

The slide: magic number, 0.82. Green. Sitting in the "healthy" band, next to a proposed 40% increase in paid acquisition spend.

What wasn't there: the channel split. Pulled it apart — paid acquisition was running at 0.3. Outbound at 0.9. Inbound organic well over 1.

The blended 0.82 was inbound carrying a paid channel that was actively destroying capital. And the recommendation on the slide was to put more money into exactly that channel.

The fix: never present a blended magic number without the channel breakdown underneath it. Three rows instead of one. The conversation stops being about the score and starts being about where the money goes.

Stage adjusts all of it. At Series A, 0.6–0.75 is often fine if you're still refining ICP — trajectory matters more than level. At Series B, the threshold tightens and volatility becomes its own problem, because it suggests the engine isn't systematized. At Series C, sustained above 1.0 is table stakes.

ACV changes how you read it too. Enterprise businesses at $50K+ deals will have volatile quarterly numbers because deal timing dominates — use a trailing four-quarter average. Low-ACV high-velocity businesses should be consistent, so a single deviating quarter is real signal rather than noise.

For reference, IVP's benchmark data puts the average magic number at $15M ARR around 1.2, with the top quartile at 2.1 or higher. By $200M+ ARR the average drops to roughly 0.8 as saturation sets in — still acceptable at that scale.

The standard formula treats every dollar of ARR as equal. It ignores what it costs to deliver that revenue.

Standard number of 0.85 at 62% gross margin becomes 0.53 adjusted. That's not a rounding difference. That's moving from "healthy" to "fix the engine first."

Which brings me to the second story.

Series B process. Headline magic number: 1.1. The investor's diligence team recalculated on a gross-margin-adjusted basis and got 0.78.

Gross margin had compressed from 76% to 71% over four quarters — the company was signing bigger deals with more implementation services attached. The standard formula caught the deal volume. It didn't catch the margin compression.

The investor said it plainly: the headline says efficient, the adjusted number says gross profit per S&M dollar is declining.

Didn't kill the deal. Valuation came in about 15% below the founder's anchor.

If your gross margin is under 70%, run both versions. Present both. The gap between them is the conversation you want to be leading, not defending.

Below 0.5. Stop scaling — CEO and board own that call. Then run a cohort churn analysis to find whether the problem is new-logo performance or retention erosion, because those need completely different fixes. Audit ICP by segmenting the last twelve months of closes by vertical, ACV, and company size. Where win rates and NRR are both strong — that's your real ICP, not the one in the deck.

0.5–0.75. Hold spend flat and work on conversion rate. A 20% improvement in demo-to-close moves the number more than a 20% budget increase at this stage. Then segment by channel and ACV, because that's where the leak is hiding. And model a churn reduction — going from 2.5% to 2.0% monthly often adds more to the numerator than any realistic S&M increase.

Above 1.0. Model a 20–30% S&M increase and calculate what it does to runway. But first, check for the thing at the top of this email: is the number high because you're efficient, or because you're capacity-constrained? Pipeline coverage above 5x forward quota with a small AE team is the tell. If that's the case, add closing capacity before you add marketing spend.

And track the trajectory. A number that went 1.4 → 1.1 → 0.9 over three quarters is deteriorating even though the current reading still looks fine.

Calculating on total revenue. Professional services in the numerator overstates efficiency — different margins, non-recurring, not driven by your S&M motion. If your P&L doesn't cleanly separate recurring from non-recurring, fix that before calculating any unit economics metric.

One blended number to the board. An enterprise motion and a self-serve motion in the same company have completely different magic numbers. The average conceals which one to fund.

Treating it as standalone. 0.8 at 85% gross margin and 110% NRR is a different business than 0.8 at 55% and 88%. Always report it next to gross margin and NRR in the same view.

Reading a quarter as a verdict. One long-cycle enterprise deal slipping distorts a quarter. So does one pulling in early. Track the trailing four-quarter average alongside the current reading; flag deviations over 20%.

Missing what a high number at low ARR means. 1.4 at $3M ARR often means the motion works at a scale that hasn't tested repeatability yet. Valid signal, not generalizable to a bigger investment decision. Pair it with cohort retention when you present it pre-Series B.

If you can't split your ARR change into new, expansion, contraction, and churn, you cannot diagnose what's moving your magic number. You can only report that it moved.

That split is what separates a number driven by genuine acquisition efficiency from one being propped up by upsell into the existing base. Two very different businesses, identical score.

Most companies at $5–20M ARR are still doing this in a spreadsheet with no single source of truth — which means the number in the board deck has assumptions baked into it that nobody owns.

Calculate both versions. Recurring revenue only, prior-quarter S&M in the denominator. Then the gross-margin-adjusted one. If they diverge materially, that gap is the board conversation.

Segment by channel and ACV band. The blended number hides where the efficiency is and where it isn't.

Report it next to NRR and CAC payback. A magic number without those two is a number with no decision attached to it.

The metric is one of the cleanest signals in SaaS finance. It's also one of the most passively reported. It sits in the deck, gets nodded at, and then the room moves on to the pipeline conversation — which is exactly backwards, because this is the number that tells you whether the pipeline conversation should end in more spend or less.

The magic number is one of the cleanest signals in SaaS finance and one of the most passively reported.

It sits in the deck. Gets a nod. Then the room moves to the pipeline conversation — which is backwards, because this is the number that should decide whether the pipeline conversation ends in more spend or less.

Two things to hold onto.

A high number isn't automatically good news. Sometimes it means you're efficient. Sometimes it means you're under-resourced and leaving revenue in the pipeline, which is what was happening to the founder at the top of this email.

And the number you present isn't necessarily the number an investor calculates. If your gross margin is under 70%, run the adjusted version yourself. The gap between the two is a conversation you want to be leading rather than defending.

Calculate both. Segment it. Report it next to NRR and payback.

Then use it to actually decide something — which is the part that almost never happens.

Reply "MAGIC" and I'll send the magic number dashboard — both formulas, the channel and ACV segmentation, trailing four-quarter view, and the ARR-change reconciliation that makes the whole thing diagnosable.

Wrote most of this on a train to Barcelona with terrible wifi and surprisingly good coffee.

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