Reuse lookup
=LET(id, A2, rate, XLOOKUP(id, Keys, Rates), qty, B2, rate*qty) names id and rate before multiply.
What is LET in Google Sheets?
LET assigns names to calculated values inside one formula, then uses those names in the final expression. Repeated VLOOKUP keys, tax rates, or date bounds appear once, which shrinks formulas and can reduce recalc work on heavy sheets.
When to use it
Use LET when the same subexpression repeats many times in one formula or when naming clarifies multi-step financial or lookup logic.
When to skip it
Skip LET for trivial one-reference formulas. Helper columns may teach better for beginners.
How it works
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Alternate name1, value1, name2, value2 pairs after LET(.
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Put the final calculation last using the names you defined.
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Names are local to that formula only, not workbook-wide.
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Define names before you use them; order matters.
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Combine LET with LAMBDA for readable advanced array formulas.
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Compare recalc time before and after on slow sheets with repeated lookups.
Examples in Google Sheets
Tax calc
=LET(gross, C2, exempt, D2, (gross-exempt)*0.22) clarifies taxable base.
Long IF chain
=LET(score, E2, IFS(score>=90, "A", score>=80, "B", TRUE, "C")) names score once for readability.
Build this without starting from a blank cell
Use a Better Sheets tool for LET, then watch a walkthrough when you want the full pattern.
Better Sheets resources
Common mistakes
- Using a name before its value pair is defined.
- LET name colliding mentally with named ranges on the sheet.
- Over-LETting simple formulas that were clearer before.
- Expecting LET variables to persist across cells; they do not.
- Circular reference by naming something that depends on itself.
Frequently asked questions
- LET vs named range?
- Named ranges are workbook-level. LET names exist only inside one formula.
- Does LET speed up sheets?
- It can when the same expensive subexpression repeated many times is computed once.
- LET vs LAMBDA?
- LET names values in one formula. LAMBDA defines reusable functions.
- How many names in LET?
- Multiple pairs allowed before the final expression.
- LET with arrays?
- Named values can be arrays used in later steps of the same formula.
- Why #NAME? on LET?
- Typo in LET or unsupported in very old Sheets clients.
- LET readability tips?
- Pick short meaningful names like rate, qty, and base.
Related Tutorials
Watch how LET works
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Related blog posts
Guides that explain LET in more depth.
What's Better Than Google Sheets?
Nothing is better than Google Sheets. You just need to learn more about the unlimited power of Google Sheets. Functions, Formulas, Apps Script and more.
Read post →The Most Popular Google Sheet Tutorial on the IF() Formula
The IF() formula is a logical function that makes it easy for users to compare a certain value and an expected value. It takes a look at a value to see if basic conditions are met.
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Users can also customize the appearance of their spreadsheets with different fonts, colors, and themes.
Read post →Related glossary terms
LAMBDA
LAMBDA defines an anonymous function inside a formula. You name parameters, write the calculation, then pass arguments when you call it. Combined with MAP, BYROW, or a named LAMBDA in the Name manager, it replaces fragile copy-paste logic across big tables.
Read guide →IFS
IFS runs several condition-result pairs in order and returns the result for the first condition that is TRUE. It replaces long nested IF trees for tiered scoring, bonus bands, and SLA buckets where each step tests a comparison.
Read guide →SWITCH
SWITCH evaluates an expression against a list of case values and returns the result for the first match. A default value catches everything else. It cleans up nested IF chains when you compare one cell to many constants like status codes.
Read guide →MAP
MAP walks aligned arrays element by element and applies a LAMBDA to each position. Pass one array for unary transforms or several arrays for element-wise combinations. It is the modern replacement for many ARRAYFORMULA column operations.
Read guide →Done reading about LET?
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