Churn crisis: SaaS ROI & cash runway model

How a company that looks fine dies

Everything on the acquisition side of this business works. Seven percent monthly growth is genuinely strong, the sales motion is clearly functioning, and a board deck built on new-logo counts would read well for several quarters in a row. The company still fails, and it fails in a specific and instructive way: at eight and a half percent monthly revenue churn against seven percent growth, the installed base shrinks every single month. Revenue is lower in year two than in year one, lower again in year three, and lower every year after that. The company ends the five years materially smaller than it started, having sold hard the entire time.

The unit economics explain it in one line. The average account here lasts a shade under twelve months, and it takes very nearly that long for the account to repay its own acquisition cost out of gross profit. The typical customer pays back what they cost to win in roughly the month they cancel. The LTV:CAC ratio lands a hair above one — technically not inverted, practically indistinguishable from it. There is no margin for a bad cohort, a pricing mistake or a competitor discount, because there is no margin at all. Every customer is a break-even trade, and the business is running that trade at volume.

This next part is the most useful thing on the page and it takes ten seconds to check. The re-investment rate is set at fifty-five percent, and it does absolutely nothing. Across all sixty months the model spends nothing on paid acquisition, because it only re-invests positive operating profit and this profile never has any — not once, in five years. Move the control from zero to ninety and every output is identical to the last decimal. The same applies to CAC: lowering it improves the printed ratio and changes neither the runway nor the ending cash, for exactly the same reason. Any growth plan that funds itself from operating profit is not a plan here. It is a description of a company that does not exist.

Retention is the right lever, and on this balance sheet it is not sufficient on its own. Take churn from eight and a half to three percent and the business becomes fundamentally sound — it breaks even inside the third year and finishes the fifth with real cash. It still runs through zero on the way there, because the fix takes time to compound and the cost base does not pause while it does. Retention alone would need to get all the way down near one and a half percent to keep the cash balance positive throughout, which is not a realistic ask of a company currently at eight and a half. What the model is saying is that this needs two moves, not one, and most teams in this position spend a year looking for the single one.

The second move is the cost base, and the combination is what works. Hold churn at three percent and take the team from fourteen engineers to ten, and the company stays solvent the whole way through and breaks even in the second year. Cutting headcount by itself is not a fix — halving the team roughly doubles the runway and the model still never reaches a single profitable month across sixty of them — but it buys the quarters that the retention work needs in order to land. Cuts alone extend the failure. Retention alone arrives too late. Together they are a company.

Outrunning the problem with acquisition is the option most teams reach for, and the model prices it honestly: organic growth would have to roughly double, to something over fourteen percent a month sustained for five years, before growth alone keeps this business solvent. That is not a plan, it is a hope with a spreadsheet attached. And there is a final indignity worth noticing on this profile. The strategy is set to Hybrid, which means it carries both a licence bill and an internal platform to maintain — and across five years that software decision costs roughly a fifth of every dollar the business collects. On a healthy company that is a line item. On this one it is a meaningful share of the total, because the denominator has been shrinking the whole time. When retention goes, everything else stops being a rounding error.

What to move, and what happens when you do

Monthly revenue churn

The only input that changes the outcome. At three percent the business becomes viable but still passes through zero; it would need to reach roughly one and a half percent to stay cash-positive on retention alone.

Engineering headcount

Buys time and nothing else. Halving the team roughly doubles the runway and the model still never records a profitable month. Paired with churn at three percent, though, it is the difference between solvent and not.

Re-investment rate

Completely inert here. There is never a month of positive operating profit to re-invest, so every value from zero to ninety produces identical results. Check it yourself — it is the fastest way to see how deep the problem goes.

CAC

Same story. Lowering it improves the LTV:CAC reading on the tiles above and moves neither the runway nor the ending cash, because no acquisition spend ever happens on this profile.

Organic MRR growth

Would need to roughly double and stay there for five years for growth alone to save this. Worth setting once, to price what "we will grow through it" is actually asking for.

Churn crisis: five years at the default inputs