The Only Growth Model That Actually Explains Why You’re Growing (or Not)

The ultimate financial model that translates user behavior into real, measurable growth.

The Growth Accounting & Virality Model

You’re reporting 20% month-on-month growth. Investors approve. The team celebrates. But deep down, you have no idea what’s really driving this growth.

Is it paid? Organic? Word-of-mouth? Luck? If you turned off spending tomorrow, would the growth hold, or collapse?

Most founders can’t answer that. Yes, they might be tracking metrics, but what’s the point if you’re tracking the wrong ones? Top-line Monthly Recurring Revenue (MRR) or active users can mask weak retention. Customer acquisition costs (CAC) can look fine even when acquisition is decaying.

“Growth” becomes a story you hope is true. It’s not an active system that you know is working.

And this model changes that.

We built a framework that decomposes growth into its real drivers, like acquisition, retention, resurrection, churn, and virality, and ties each back to unit economics. The goal is to have a live instrument panel. You can run scenarios, spot fragility, and see where growth is compounding and where it’s leaking.

Think of it as growth accounting and sanity check at the same time. One part cohort model, one part revenue engine, one part.. BS detector.

If you want to know whether your growth is sustainable, or just subsidized, this is the model that finally tells you the truth.

Do you know what drives your growth?

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Table of Contents

1. Why This Model Matters

2. Inside the Model - Section by Section

3. Who Should Use It

4. Download the Model

5. How It Works

6. FAQ: Your Growth Model Questions, Answered

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1. Why This Model Matters

Growth can look great on paper. Most trackable metrics will tell you the story you need to hear. Active users are up, acquisition costs are steady, and your MRR curve bends in the right direction.

But underneath, something’s off, and you can’t quite tell what. That’s the trap most dashboards set. They measure surface-level motion instead of underlying momentum.

How can you keep growing if you don’t know the real story?

This model forces you to look under the hood.

Most dashboards hide what’s really driving your growth. A proper growth accounting model reveals the problems you don’t see on the surface.

Most Growth Metrics Lie

Traditional dashboards tell you what happened, but not why. They’re full of metrics that sound useful like CAC, LTV, Net New MRR and so on. But those metrics rarely isolate what’s driving those changes.

You can be acquiring more users and still be shrinking. You can hit your MRR goal and be leaking value through churn. You can post a killer retention chart but miss the fact that it’s only true for one high-converting cohort.

Growth without decomposition is just storytelling. And when capital is tight, that kind of storytelling gets founders in trouble.

Growth Accounting Exposes What’s Real

This model starts with a deceptively simple equation:

Activeₜ = Activeₜ₋₁ + Newₜ + Resurrectedₜ − Churnₜ

Churned users who were active in the previous period but did not return in the current period. Resurrected are the users who were previously churned (inactive) but became active again in the current period.

Resurrected users—those who return after churning—are one of the most overlooked but powerful drivers of sustainable growth.

By separating new users, resurrected users, and churned users, you can see which levers are actually creating net growth. If “New” is entirely paid and retention is cratering, you’re essentially buying a leaky bucket. If “Resurrected” is spiking after a product nudge, you’ve found a free win. Every driver becomes inspectable, testable, and ultimately, optimizable.

The model’s cover sheet gives operators a clear map of the core building blocks—inputs, cohorts, growth accounting, unit economics, and output dashboards.

A Model That Ties Marketing, Product, and Finance Together

Most teams stare at different sides of the same mountain.

For example, marketing obsesses over CAC and channel efficiency. The product team focuses on activation and retention, while finance is trying to model out LTV:CAC and payback periods.

This model is the shared language across all three. It doesn’t just describe growth, it also explains how product inputs turn into financial outputs, and where acquisition strategy either compounds or stalls.

If you’re tired of team debates that sound like different languages, this is the unifying framework.

It Protects You From Vanity Growth

Here’s the litmus test: If you stop running ads tomorrow, do you still grow next month?

If the answer is no, then you’re not growing. The truth is that you’re simply spending to show vanity metrics. A mirage.

This model makes that truth visible. It separates paid acquisition from organic growth, isolates virality, and tracks resurrection trends, all zero-CAC sources of compounding.

• If your viral coefficient is >0.2, you’ve got healthy word-of-mouth.

• If resurrection is >10% of churn, users want to come back.

• If retention is flattening after month 2, the product is earning its keep.

None of that shows up in a standard growth chart, but it shows up here.

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2. Inside the Model - Section by Section

Most models either show you what already happened or let you dream up what could. This one does both, and tells you how.

It’s designed to be fully interactive, so you can test assumptions, watch dynamics unfold over time, and see the connection between user behavior and financial outcomes.

Here’s how the architecture works, one tab at a time.

Inputs & Assumptions

Everything starts here. The model asks for a few baseline truths, like your starting month, how long you want to project forward, and your core growth drivers.

You’ll define the mix of paid vs. organic acquisition, set a virality multiplier (K-factor), specify monthly retention and resurrection curves, and input unit economics like Average Revenue Per Account (ARPA) and gross margin.

The best part is that this sheet is dynamic. If you change any input, the entire model responds. If, for instance, virality drops from 0.4 to 0.1, or if churn after Month 2 improves by 10%, you’ll see it ripple instantly through your cohorts, your revenue, your payback period.

All growth projections start with realistic assumptions—acquisition mix, virality parameters, activation, monetization, and retention. Change an input here and see the entire model react.

Cohorts

Rather than lumping users together, the model treats each signup month as its own cohort. Every group of users is tracked over time, month by month, so you can see how long they stick around, and how much value they generate.

The cohort view shows real product truths. For instance, if retention flattens early, you’ve likely nailed activation. If one month performs drastically better, maybe a feature change or campaign worked, and you can double down.

The survival curve doesn’t lie. When you track cohorts instead of just counting active users, you are measuring growth and understanding it too.

Cohort tracking reveals the truth about retention, churn, and product stickiness—insights you never get from aggregate user metrics.

Growth Accounting

Here’s where it all comes together. This tab runs the full user P&L. For each month, it tracks:

• New users broken down into paid, organic, and viral

• Churned users, who leave the product

• Resurrected users, who come back after churn

Then it ties those together:

Activeₜ = Activeₜ₋₁ + Newₜ + Resurrectedₜ − Churnₜ

This formula gives you a true diagnostic of momentum. If net active users are growing but churn is creeping up, you’ll see the tension. If virality or resurrection is silently boosting you, the model will catch it. If growth vanishes the moment you pause paid spend, you’ll know exactly why.

Growth accounting decomposes growth into its real drivers: new users, churn, resurrection, and virality—your startup’s actual growth engine.

Unit Economics

Users are great, but they don’t pay salaries. Revenue does. This section converts the user flows into financial outcomes.

Using ARPA, CAC, and gross margin assumptions, the model calculates monthly revenue, CAC payback periods, LTV, and your LTV:CAC ratio. These aren’t fixed numbers you calculate once. They change over time as your acquisition mix, retention curve, and resurrection behavior evolve.

What you get is a running view of financial health; whether each new user cohort pays back efficiently, whether virality lowers your blended CAC, and whether retention makes your customer lifetime profitable, or expensive. This is where growth gets priced.

The unit economics view connects user behavior to financial outcomes—ARPU, CAC, payback, and LTV—to validate whether growth is sustainable.

Output Dashboard

Finally, this is the front-end that pulls it all together. This tab offers a visual snapshot of what’s happening, with clear charts and operator-ready KPIs including:

• Net active user growth over time

• Viral coefficient (K) trends

• Churn and resurrection patterns

• CAC payback curve

• LTV:CAC trajectory

Each graph updates as you tweak the model. It’s designed so you don’t need to open five tabs to understand one outcome.

Here’s what the monthly KPIs look like:

A single dashboard visualizes net growth, churn, revenue, virality, and CAC efficiency—your startup’s real-time control tower.

Your “Active Users” chart:

Active user growth visualized month-by-month, reflecting the combined impact of acquisition, retention, virality, and resurrection.

And most importantly, a diagnostic chart that lets you know what your users look like at any time:

A breakdown of user sources highlights what’s driving growth—and what’s silently draining it—across paid, organic, referral, and resurrected segments.

This is what a startup “control tower” looks like. A tidy, professional model that any founder can use.

Whether you’re preparing for a fundraising round, or a board meeting, if you are just testing retention strategies, or modeling a price increase, this is where the story sharpens. And if your growth is fragile, you’ll see that too, before the bank account does.

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3. Who Should Use It

This model isn’t built for finance nerds or growth hackers. It’s built for operators, for people who need to understand what’s actually driving their startup forward, and what happens when the fuel runs out.

It’s designed for optimal “user friendliness”, or even better, “founder friendliness.”

Founders / CEOs

If you’re steering the company, you need to know whether your growth is earned or borrowed. This model lets you pressure-test your metrics and ask: “If we paused spend, does anything still grow?”

Growth & Marketing Leads

Use the model to separate channel performance from actual user behavior. Are your campaigns acquiring quality users? Is virality compounding or just a one-off spike?

This is where you find out.

Product Teams

Features that improve retention, activation, or resurrection often take time to show results. The cohort view and survival curves in this model give you clear evidence, month over month, of whether those bets are working.

Finance / Investors

LTV and CAC mean nothing if retention is falling apart. This model connects user behavior to unit economics, so you can validate whether growth is profitable, or just temporarily impressive.

Ultimately, this isn’t just a tool for one department. It’s designed to be a cross-functional alignment layer designed to give marketing, product, and finance one shared source of truth.

When everyone’s working from the same assumptions, decisions get faster, meetings get shorter, and the business moves forward with clarity.

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4. Download the Model

This model gives you both the numbers and the narrative: what’s driving growth, what’s stalling it, and what happens if spending stops.

Download the Growth Accounting & Virality Model 👇