What is legacy array in Google Sheets?
Array formulas compute across many cells at once. Google Sheets now spills results automatically; older CSE array habits still appear in legacy tutorials.
When to use it
Use this concept when building formulas that must scale, spill correctly, or stay readable for teammates.
When to skip it
Skip advanced mechanics when a single built-in function or pivot already returns the answer with less setup.
Better Sheets resources
Related Tutorials
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Related blog posts
Guides that explain legacy array in more depth.
Related terms
Google Sheets formulas
A formula is an instruction in a cell that calculates a result from other cells, ranges, or built-in functions. Every formula begins with =. When inputs change, the sheet recalculates so dashboards and models stay live without manual copy-paste. Formulas are the default automation layer inside the grid before Apps Script or add-ons.
Read guide →ARRAYFORMULA
ARRAYFORMULA tells Google Sheets to treat a formula as an array operation so one expression fills many cells at once. It is common with IF, VLOOKUP, and math on full columns before dynamic arrays made many patterns automatic. It still matters for legacy sheets and explicit control.
Read guide →#SPILL! error
#SPILL! means a dynamic array formula tried to fill multiple cells but something blocked the spill range. Another value, merged cells, or a table in the way stops the output. Clear the obstruction or move the formula to open space.
Read guide →Recalculation
Recalculation is when Google Sheets recomputes formula results after something changes. Most functions update when their input cells change. Volatile functions like NOW, RAND, and OFFSET recalculate more often. Large workbooks may feel slow when thousands of formulas refresh at once.
Read guide →Done reading about legacy array?
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