How to use LET to write readable formulas in Excel and Google Sheets

Step by step

1. 1Identify the sub-expressions in your formula that are repeated or hard to read. For example, a discount formula: base price array * (1 - discount rate array).
2. 2Open LET: =LET(name1, expr1, name2, expr2, ..., result_expression).
3. 3Assign base = A2:A6 (price column) and adj = B2:B6 (discount rate column).
4. 4Define discounted = base*(1-adj) — this is the intermediate array, named for clarity.
5. 5The final expression SUM(discounted) returns the total revenue after discount without repeating the multiplication formula.

Tips

• Keep variable names short but descriptive (base, adj, net, ratio). Avoid generic names like x or v1.
• LET evaluates each name once in sequence, so later names can reference earlier names. Use this to chain steps logically.
• When debugging, temporarily change the last LET expression to one of the intermediate names (e.g., replace SUM(discounted) with discounted) to inspect that intermediate value.

Frequently asked