Goal Seek is a handy tool in Excel that helps you work backward from a desired outcome to find the input value needed to achieve it.

Here's how to use it:

Scenario: Imagine you run a bakery and want to know how many cupcakes you need to sell to reach a specific revenue target.

Steps:

1. Set Up Your Spreadsheet:

- In one cell (e.g., B1), enter the price per cupcake (let's say $2).
- In another cell (e.g., C1), enter the desired revenue target (e.g., $100).
- In a third cell (e.g., A1), use a formula to calculate total revenue based on price and number of cupcakes sold (e.g., =B1D1, where D1 is the cell where you'll enter the number of cupcakes).

2. Access Goal Seek:

- Go to the "Data" tab on the Excel ribbon.
- In the "What-If Analysis" group, click "Goal Seek."

3. Define Your Goal:

- Set cell: Enter the cell reference containing your desired outcome formula (e.g., C1, the total revenue cell).
- To value: Type the specific revenue target you want to achieve (e.g., 100).

4. Define the Input Variable:

- By changing cell: Enter the cell reference where you'll input the number of cupcakes (e.g., D1). This is the variable you'll adjust to reach your goal.

5. Click OK: Excel will perform calculations and automatically adjust the value in the "By changing cell" (number of cupcakes) until the formula in the "Set cell" (total revenue) reaches your desired "To value" (revenue target).

Result: In this example, Excel might show you that you need to sell 50 cupcakes (displayed in cell D1) to reach your $100 revenue target (in cell C1).

Key Points:

- Goal Seek works best with single variable problems. For more complex scenarios, consider using Solver, another What-If Analysis tool.
- Ensure your formula in the "Set cell" is set up correctly to reflect the relationship between the input variable and the desired outcome.
- Goal Seek only finds one solution. If there are multiple ways to reach your target, you might need to adjust other variables or use a different approach.

By using Goal Seek effectively, you can save time and effort by working backward from your desired results to determine the necessary input values.