Load your history.

You choose a file from your computer and this page reads it right here, in your browser. It is never sent to a server — not mine, not anyone’s. This page carries no analytics and no session recording. If you’d like to see that for yourself, disconnect from the internet before you choose the file: the light below turns red, and the page keeps working.

Your file — one row per month: month, net sales (after refunds, before tax), and end-of-month inventory at cost if you track it (.xlsx or .csv)

Use the numbers your bookkeeping already has; the math reads the shape of your months, not their size, so dollars or units both work if you’re consistent. At least 36 months; 48+ if your business has seasons; 60+ is ideal. Template · or export straight from QuickBooks, Square, or your point-of-sale. No file handy? The demo and the industry runs are on the diagnostic page.

Choose a file and your history renders here. The report can be saved to your machine afterward.

Measurement, not advice. Jae Kim · [email protected] · method and code at laggingtruth.com.