Excel like a finance pro.
LET
Dynamic arrays (Microsoft 365)Name a value or calculation once, then reuse it — faster formulas that read like plain English.
Difficulty
1What is it?
LET assigns names to values or sub-calculations and then uses those names in a final formula. You define each name once — a cell, a number, or a whole expression — and refer to it as many times as you like; Excel computes each one a single time, so a long formula that repeated the same lookup or expression becomes both quicker and far easier to read. Microsoft 365 / Excel 2021+.
2What it looks like
LET(name1, value1, [name2, value2, …], calculation)- name1
- A name for the first value, like a variable — letters and numbers, no spaces.
- value1
- What that name stands for: a cell, a number, or a formula.
- [name2, value2, …]
- More name/value pairs. Each one can use the names defined before it.
- calculation
- The final result, written using the names — this is what the cell returns.
3When you use it
- Compute something once (a lookup, a date, a rate) and reuse it several times in one formula.
- Make a gnarly nested formula readable by naming its parts.
- Speed up a slow sheet where the same expensive expression repeats.
4See it in action
Change the inputs — the formula and result update live. Prefer the real thing? Download the Excel file and open it in Excel.
Name revenue and COGS, derive gross profit from them, then return the margin — all in one readable formula. Edit B2 or B3.
=LET(rev, B2, cogs, B3, gp, rev - cogs, gp / rev)60.0%| A | B | C | |
|---|---|---|---|
| 1 | Field | Value | Result |
| 2 | Revenue | 60.0% | |
| 3 | COGS |
The lime cell holds the formula — click it (or any cell) to see its contents in the bar above, just like Excel. Edit the blue cells to watch it recompute.
5Common errors
#NAME?A name is misspelled — or you're on a version without LET.Fix: Check each name matches its definition; LET needs Microsoft 365 or Excel 2021+.
Name isn't recognizedA name is used before it's defined.Fix: Define each name earlier in the LET than the point where you use it.
Too few argumentsThe formula doesn't end with a final calculation, or a pair is incomplete.Fix: Always finish with the result formula, and give every name a value.
6Better functions & alternatives
- Named ranges — Workbook-wide names, versus LET's names that live inside a single formula.
- LAMBDA — Turn a LET-style calculation into your own reusable, named function.
- Helper cells — The old way — break the steps into extra cells instead of naming them inline.
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