Someone Sent You a Google Sheets Model. Do This Before You Touch a Number.

A junior sends you their revenue build. A banker shares a 3 statement model. The FP&A book gets handed to you because someone left. Now its your model, and you have no idea whats a formula, whats typed over, or what breaks if you touch it. Here is the five minute check I run before I change a single number.

Minute 1: Auto Color the Tab You Care About

In Excel you would eyeball the colors. Blue means input, black means formula, green means it came from another sheet. In Sheets nobody colors anything, so you cant trust your eyes. Select the whole tab and press Ctrl + Shift + S (Cmd + Shift + S on Mac). Auto Color classifies every cell and colors it: hardcodes blue, formulas black, same sheet references purple, cross sheet links green.

You are looking for one thing: blue cells sitting in the middle of formula rows. That is where someone typed over a formula to force a number. A banker sent me a revenue build a while back where the growth rate row looked clean. Auto color showed three months in the middle were hardcoded. The totals tied out, but the model was not doing what the labels said it was doing.

Minutes 2 and 3: Trace What Feeds the Number

Pick the output that actually matters. Ending cash, EBITDA, the headline growth number. Select it and run Trace Precedents: press Ctrl + Shift + [. Every cell that feeds it lights up, including cells on other tabs. Two hops in and you know whether the number is really built up or wired to some tab called Scratch v3.

Then flip it. Before you change any input, select it and press Ctrl + Shift + ]. Trace Dependents highlights every formula that uses that cell, on any tab. If you are about to overwrite an assumption, this is how you find out what breaks before it breaks.

Minutes 4 and 5: Scan the Whole Book

If the book is big or already feels slow, press Alt, then A, W, P (Option on Mac). The Performance Audit scans every formula in the workbook and ranks the usual suspects: volatile functions like NOW and TODAY, full column lookups, IMPORTRANGE chains, INDIRECT and OFFSET. Each finding links to sample cells so you can jump straight to the offender. In a 20 tab book, the top handful of findings are usually the whole problem.

That is the whole audit. Color it, trace it, scan it. If everything comes back clean, go ahead and change your number. If it does not, at least you found out before your version went to the boss. Everything here is XLKeys Pro, 30 day free trial, no card.

Next time someone sends you a model, run this before you touch it. Get XLKeys on the Chrome Web Store and press Ctrl + Shift + S.