📊 Excel LET Function
Simplify Complex Formulas with Named Variables
The LET function assigns names to calculation results, allowing you to store intermediate values and reuse them throughout your formula. This makes complex formulas easier to read, write, and maintain while improving performance by eliminating redundant calculations.
Think of LET as creating “variables” within your Excel formula – just like in programming, you can define a value once and use it multiple times without recalculating it.
=LET(name1, value1, [name2, value2, ...], calculation)
| Parameter | Description | Required |
|---|---|---|
| name1 | The name you want to assign to your first value (cannot be the output of a formula) | ✅ Yes |
| value1 | The value, cell reference, or calculation to assign to name1 | ✅ Yes |
| name2, value2… | Additional name-value pairs (you can have up to 126 pairs) | ❌ Optional |
| calculation | The final calculation that uses the named values and returns the result | ✅ Yes |
Assign values to variables
Excel calculates once
Reference by name
Final calculation
📦 Scenario: Calculate Total Order Cost with Discount and Tax
You need to calculate the final price for an order that includes:
- Original price: $1,200
- Discount: 15%
- Tax rate: 8%
Sample Data:
| Item | Value |
|---|---|
| Original Price (A2) | $1,200 |
| Discount Rate (B2) | 15% |
| Tax Rate (C2) | 8% |
📝 Formula with LET:
price, A2,
discount, B2,
tax, C2,
discountedPrice, price * (1 – discount),
finalPrice, discountedPrice * (1 + tax),
finalPrice
)
Issues:
- Hard to read and understand
- Difficult to debug
- No intermediate values visible
- Complex formulas become unmanageable
price, A2,
discount, B2,
tax, C2,
discountedPrice, price * (1 – discount),
finalPrice, discountedPrice * (1 + tax),
finalPrice
)
Benefits:
- Clear, self-documenting code
- Easy to troubleshoot
- Calculations done once
- Intermediate steps are visible
Choose meaningful variable names that explain what the value represents. Use “totalRevenue” instead of “x” or “tr”.
LET can significantly speed up complex formulas by avoiding redundant calculations. If you reference VLOOKUP(A2,$D$2:$E$100,2,0) three times in a formula, LET will calculate it only once.
Break down complex formulas into logical steps. This makes debugging easier and helps others understand your work.
When troubleshooting, you can temporarily return intermediate values instead of the final result to see what’s happening at each step.
Variable names must start with a letter and cannot contain spaces or special characters (except underscores). They also cannot match cell references (e.g., don’t use “A1” as a name).
LET works beautifully with LAMBDA, FILTER, SORT, and other modern Excel functions to create powerful, reusable formulas.
Calculate Employee Bonus Based on Performance
baseSalary, A2,
performanceScore, B2,
yearsOfService, C2,
performanceBonus, baseSalary * (performanceScore / 100) * 0.15,
loyaltyBonus, baseSalary * (yearsOfService / 10) * 0.05,
totalBonus, performanceBonus + loyaltyBonus,
totalBonus
)
This formula clearly shows each component of the bonus calculation, making it easy to understand and modify.
- LET simplifies complex formulas by allowing you to name and reuse calculations
- Improves performance by calculating each value only once
- Makes formulas self-documenting with meaningful variable names
- Easier to debug and maintain compared to nested formulas
- Available in Excel 365 and Excel 2021
- Works with all Excel functions and can be combined with LAMBDA for even more power
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