Formulas & functions

Type = in any cell and you’re writing a formula. The engine follows the conventions you know from Google Sheets and Excel — same reference style, same function names, same error values.

Writing a formula

1. Select a cell and type =.
2. Reference other cells by their coordinates: =A1*B1.
3. Press Enter — the cell shows the result; the formula bar shows the formula whenever the cell is selected.

• Ranges use the A1:B10 form: =SUM(A1:A10) totals a column segment.
• Absolute references use $ to pin an axis: =$A$1 never moves when copied; =A$1 pins just the row. This matters when copying formulas.
• Formulas recalculate instantly as their inputs change — including inputs edited by someone else in the sheet.

Tip

References follow the data, not the coordinates. Insert a row above your table and every formula pointing into it keeps pointing at the right cells — no silent off-by-one.

The function library

Over 270 functions are implemented across math, text, date, logical, lookup, statistical, financial, engineering, and array categories. Click the ƒx button to browse and search the catalog — choosing an entry inserts NAME( into your formula so you can fill in the arguments.

The everyday dozen:

Function	What it does	Example
SUM	Adds numbers or ranges	=SUM(B2:B20)
AVERAGE	Arithmetic mean	=AVERAGE(B2:B20)
IF	Value based on a condition	=IF(C2>100, "over", "under")
COUNTIF	Count cells matching a condition	=COUNTIF(D2:D50, "done")
SUMIF	Sum cells whose neighbors match	=SUMIF(A2:A50, "widgets", B2:B50)
VLOOKUP	Find a row by its first-column key	=VLOOKUP("acme", A2:D50, 3, FALSE)
INDEX	Value at a position in a range	=INDEX(B2:B50, 7)
MATCH	Position of a value in a range	=MATCH("acme", A2:A50, 0)
TEXTJOIN	Join text with a separator	=TEXTJOIN(", ", TRUE, A2:A10)
TODAY	Today’s date	=TODAY()
DATE	Build a date from parts	=DATE(2026, 7, 16)
ROUND	Round to N decimal places	=ROUND(B2, 2)

INDEX + MATCH together make a flexible lookup: =INDEX(C2:C50, MATCH("acme", A2:A50, 0)). CONCATENATE also exists for joining text, but TEXTJOIN (with its separator and skip-blanks arguments) is usually what you want.

When a formula goes wrong

Errors are explicit, never silent:

Error	Meaning
#DIV/0!	Division by zero
#N/A	Lookup found no match
#NAME?	Unknown function or name
#NUM!	Invalid numeric argument
#REF!	Reference to a deleted cell
#VALUE!	Wrong argument type
#ERROR!	The formula couldn’t be parsed
#UNSUPPORTED!	The function exists in the catalog but isn’t available — hover for why

#UNSUPPORTED! is the honesty signal: a few cataloged functions aren’t implemented yet, and a cell using one says so rather than guessing. Google-proprietary functions (like GOOGLEFINANCE or IMPORTRANGE) aren’t in the catalog at all and return #NAME?.

Details worth knowing

• Dates are spreadsheet serial numbers under the hood — date functions and arithmetic (=B2-A2 for days between) work the standard way.
• NOW, TODAY, RAND, and RANDBETWEEN are volatile — they refresh on recalculation.
• REGEXMATCH / REGEXEXTRACT / REGEXREPLACE use the same regex dialect Google Sheets documents.
• Argument separators are commas; decimals use a dot (US conventions).