SaaS finance guides

Most writing about SaaS metrics stops at the definition. That is the easy part, and it is rarely where decisions go wrong. What actually costs companies money is the second order: knowing that LTV:CAC and CAC payback describe the same relationship on different timescales, that a healthy-looking ratio can still starve a balance sheet, that a point of monthly churn quietly sets a ceiling on how large the business can ever become, and that the maintenance tail on an internal system outlives every argument made about the build estimate.

These guides are written for the person who has to make the call — a founder deciding whether to raise, an engineering leader defending a build, a finance lead sanity-checking a plan. Every figure in the tables is computed from the same engine that powers the simulator, and the assumptions behind each one are stated rather than hidden, so you can disagree with them precisely.

None of it is financial advice, and none of it is a forecast. A five-year model compounds its own assumptions sixty times; the useful output is not the number at the end but an understanding of which inputs actually move it.

There are 12 guides below, grouped by what they are about. If you want a definition rather than an argument, the metrics glossary covers every measure the model computes, with its formula, and the calculators work out any of them from your own numbers. Everything here is written and maintained by Assaf Schwartz; none of it is sponsored, and no guide recommends a product.