Guides

LET Function in Excel: Name the Parts of a Long Formula

By Ravindra Bagale, Excel & Data Analytics trainer · LinkedIn · Published: 6 October 2026 · Last updated: 6 October 2026

Raja's bonus formula repeats B2/C2 three times: once to check if the target is met, once for the 120% slab and once inside the result. When the rule changes, he has to edit all three places. With LET he names B2/C2 as ach once and uses the name everywhere.

LET lets you create names inside a formula: =LET(name1, value1, [name2, value2, ...], calculation). Each value is worked out once, and the last argument is the result. It needs Microsoft 365 or Excel 2021 and later.

Download the practice file (let-function.xlsx)

Excel file, 7 KB. It has the sample data used below. All numbers in this workbook are fictional teaching data, not real company figures.

=LET(ach,B2/C2,rate,IF(ach>=1.2,5%,2%),IF(ach<1,0,ROUND(B2*rate,0)))

Before and after

The bonus rule: no bonus below 100% of target, 2% of sales from 100%, and 5% of sales from 120%.

Without LET:
=IF(B2/C2<1,0,ROUND(B2*IF(B2/C2>=1.2,5%,2%),0))

With LET:
=LET(ach,B2/C2,rate,IF(ach>=1.2,5%,2%),IF(ach<1,0,ROUND(B2*rate,0)))

Both formulas give the same answers; the LET version says what it means. To change the 120% slab you edit one place.

Example 2: clean a name once, use it twice

=LET(t,TRIM(A2),PROPER(t)&" ("&LEN(t)&" letters)")

TRIM(A2) runs once and is used twice. For " zoya " the result is Zoya (4 letters).

Rules for names

• Names must start with a letter and cannot look like a cell address (ab1 is not allowed; ach is fine).
• A name can use the names defined before it.
• Names exist only inside that one formula; they do not appear in Name Manager.
• Use Alt + Enter inside the formula bar to put each pair on its own line for readability.