What is the difference between REDUCE and SCAN in Google Sheets?

REDUCE gives only the last accumulated value. SCAN returns every intermediate value as an array that spills into neighbouring cells.

Google Sheets function

REDUCE in Google Sheets

REDUCE is a built-in helper in Google Sheets, and it returns a single value from the whole range.

REDUCE(initial_value, array, LAMBDA(total, x))

For the running values rather than the final one, use SCAN; MAP returns one result per element.

For a fuller explanation of the arguments and common errors, see the REDUCE Excel guide.

Formula: C2: =REDUCE(1,A2:A4,LAMBDA(a,x,a*x))

Result: 6

The accumulator starts at 1 and is multiplied by 1, 2 and 3.

Formula: C2: =REDUCE("",A2:A4,LAMBDA(a,x,a&LEFT(x,1)))

Result: ABC

The first letter of each name is appended to an initially empty text.

Formula: C2: =REDUCE(0,A2:A4,LAMBDA(a,x,IF(x>10,a+x,a)))

Only values above 10 are added, so 5 is skipped and 20 + 12 remain.

A tiny spreadsheet with example data. Edit the formula or any number and see the result.

Formula in F2: =REDUCE(0,C2:C7,LAMBDA(a,x,a+x))

Result in F2: 350

What is the difference between REDUCE and SCAN in Google Sheets?: REDUCE gives only the last accumulated value. SCAN returns every intermediate value as an array that spills into neighbouring cells.

Google Sheets is used here only as a descriptive product name. FormulaCamp is not affiliated with Google.