Google SheetsWhere to start
New to Sheets formulas? How formulas work in Google Sheets covers the equals sign, ranges that run to the bottom of the sheet, other tabs, dollar signs, one formula for a whole column, and the locale setting that decides commas or semicolons.
Something shows an error? Errors in Google Sheets explains each code. It gives special attention to #REF!, which in Sheets usually means a spilling formula is blocked, and to #ERROR!, which other spreadsheets do not have.
Going deeper
The QUERY language, clause by clause is the longest guide and the most rewarding. QUERY can replace a whole page of formulas, and this guide walks through select, where, group by, pivot, order by, limit, label and format on one sample table, then covers dates, cell values inside a query, and the things that go wrong.
Cleaning data in Google Sheets is a set of recipes: trimming spaces, fixing capitals, splitting, extracting by pattern, converting text to numbers, and removing duplicates, by menu and by formula.
Moving between programs
Google Sheets and Excel: where formulas differ lists the functions each program has to itself, the ones with the same name and a different shape, and what to check when a file crosses over.
How to get the most from a guide
Open a blank spreadsheet beside the page and type in the small sample table. Then type each formula yourself. When one works, change it: another column, another condition, a deliberate mistake. Sheets keeps every version of a file under File, Version history, so nothing you try can do lasting harm.
This is an independent help site. It is not connected with or approved by Google. Google Sheets is a trademark of Google LLC, named here only to say which program a formula is for. The people and figures in the sample sheets are made up.