Excel has many tools that help you do complex math. One of these tools is called What-If Analysis. It helps you test different situations using your data. You can even use it when some data is missing. In this lesson, you will learn how to use a tool called Goal Seek.

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What Is Goal Seek?

Usually in Excel, you enter numbers and formulas to get a result. Goal Seek works the other way around. You start with the result you want, and Excel figures out the number you need to get that result.

Let’s look at two examples to understand how Goal Seek works.

Example 1: Passing a Class

Imagine you're taking a class. Your current grade is 65, but you need at least 70 to pass. You have one more assignment left. You can use Goal Seek to find out what grade you need on the final assignment.

Here are your grades so far: 58, 70, 72, and 60. You don’t know the fifth grade yet, but you can still write a formula to find your average. In this case, all assignments are worth the same. So, you type =AVERAGE(B2:B6) to calculate the average in cell B7.


Now use Goal Seek:

  1. Click on cell B7 (this is where the average is).

  2. Go to the Data tab.
  3. Click What-If Analysis, then choose Goal Seek.

  4. In the dialog box:

    Set cell: B7

    • To value: 70 (the grade you need)
    • By changing cell: B6 (the unknown grade)
  5. Click OK.

Excel will show the result. In this case, you need a 90 on the final assignment to pass.

Example 2: Planning an Event

Now let’s say you're planning an event. You have a budget of $500. You want to invite as many people as possible without going over budget.

Here’s how your cost is set up:

  • Room cost: in cell B2
  • Cost per person: in cell B3
  • Number of people: in cell B4
  • Total cost: in cell B5, with formula =B2+B3*B4

To use Goal Seek:

  1. Click on cell B5 (this is where the total cost is).

  2. Go to the Data tab.

  3. Click What-If Analysis, then choose Goal Seek.

  4. In the dialog box:

    Set cell: B5

    • To value: 500
    • By changing cell: B4 (number of people)

  5. Click OK.

Excel will give you a number. Let’s say the answer is 18.62. Since you can’t invite part of a person, you round down to 18 guests to stay within your budget.

Other What-If Tools in Excel

Excel also has other What-If tools:

  • Scenarios: These let you test different values in several cells at once. You can compare many situations without changing your original data.


  • Data Tables: These are useful when you want to test many values. You can see all the results at the same time. For example, you can use a data table to see different car loan payments.