# Excel LET function

## Summary

The Excel LET function allows you to assign names to calculation results, values, or define names within a formula, akin to using variables in programming. This functionality can greatly enhance formula efficiency by reducing the need to calculate the same expression multiple times and improving readability and composition of formulas by giving meaningful context to complex calculations.
##### Syntax
```				```
=LET(name1, value1, [name2, value2, …,] calculation)
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• name1, name2, …: The names you assign to variables or constants within the formula.
• value1, value2, …: The values or calculations assigned to each name.
• calculation: The final calculation that uses the named variables or constants.
##### Return value
The return value of the defined calculation.

## How to use

Define one or more name/value pairs, followed by a calculation that utilizes these pairs. LET supports up to 126 name/value pairs, enabling extensive formula customization and optimization.

## Examples

##### Simple LET
Basic Arithmetic Operation: Demonstrating the simplest use of LET to perform an addition.
```				```
=LET(x, 5, SUM(x, 1))
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Assigns the value 5 to x and then adds 1 to x, returning 6.
##### LET for Sales Data Filtering
Filtering Sales Data with Custom Formatting: Utilizing LET to streamline filtering and formatting sales data.
```				```
=LET(salesData, A2:A100, filteredData, FILTER(salesData, salesData > 500), IF(ISBLANK(filteredData), "-", filteredData))

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This example filters the sales data to show sales greater than 500 and adds a dash to any blank cells in the filtered result, enhancing data presentation and analysis.
##### LET with Multiple Variables
Combining Variables for Complex Calculation: Using LET with multiple variables to simplify a formula.
```				```
=LET(x, 10, y, 5, x + y)

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Declares x as 10 and y as 5, then adds x and y, returning 15.
##### LET for Date Range Filtering
Generating and Filtering Date Ranges: Applying LET to create a list of dates and filter out weekends.
```				```
=LET(dates, SEQUENCE(C5-C4+1, 1, C4, 1), FILTER(dates, WEEKDAY(dates, 2) < 6))

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Creates a sequence of dates between two points and uses FILTER to exclude weekends, demonstrating LET’s power in reducing formula redundancy.
##### LET for Dynamic Calculations
Calculating Compound Interest Using LET: Showcasing how LET can handle more dynamic financial calculations.
```				```
=LET(principal, 1000, rate, 0.05, periods, 10, principal * (1 + rate)^periods)

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Calculates the future value of an investment based on its principal amount, interest rate, and the number of periods, showing LET’s utility in financial modeling.