How to Use Goal Seek in Excel: Step-by-Step Guide

In Excel, use Goal Seek to find the input value needed to reach a specific result in a formula. Access it via Data > What-If Analysis > Goal Seek, then set the cell to the target value by changing another cell.

Syntax

The Goal Seek tool does not use a formula but works through a dialog box with three key inputs:

• Set cell: The cell containing the formula you want to reach a target value.
• To value: The number you want the formula result to become.
• By changing cell: The cell Excel will change to reach the target.

Goal Seek adjusts the 'By changing cell' value until the 'Set cell' formula equals the 'To value'.

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Goal Seek Dialog Inputs:
Set cell: B3
To value: 100
By changing cell: B1

Example

Suppose you want to find the sales needed to reach $100 profit. You have:

• Cell B1: Sales (input)
• Cell B2: Cost (fixed at 50)
• Cell B3: Profit formula =B1 - B2

Use Goal Seek to find the sales value that makes profit $100.

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A1: Sales
B1: 0
A2: Cost
B2: 50
A3: Profit
B3: =B1 - B2

Steps:
1. Select Data > What-If Analysis > Goal Seek
2. Set cell: B3
3. To value: 100
4. By changing cell: B1
5. Click OK

Output

After Goal Seek runs, B1 will show 150, making B3 (Profit) equal 100.

Common Pitfalls

• Wrong set cell: The 'Set cell' must contain a formula; otherwise, Goal Seek won't work.
• Changing cell must be input: The 'By changing cell' should be a cell that can be changed, not a formula.
• Goal Seek finds one solution: It may not find a solution if none exists or if multiple solutions exist.
• Static values: If cells are locked or protected, Goal Seek cannot change them.

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Wrong way:
Set cell: B1 (input cell, no formula)
To value: 100
By changing cell: B2

Right way:
Set cell: B3 (formula cell)
To value: 100
By changing cell: B1 (input cell)

Quick Reference

Step	Action
1	Go to Data tab > What-If Analysis > Goal Seek
2	Set 'Set cell' to the formula cell you want to target
3	Enter the desired result in 'To value'
4	Choose the input cell to change in 'By changing cell'
5	Click OK and wait for Excel to find the solution

Key Takeaways

Goal Seek adjusts one input cell to make a formula cell reach a target value.

Always set the 'Set cell' to a formula cell, not a static value.

The 'By changing cell' must be an input cell that Excel can change.

Goal Seek works best for simple one-variable problems.

If no solution exists, Goal Seek will notify you or stop without changes.