A data table is a range of cells in which you can change values in some in some of the cells and come up with different answers to a problem. A good example of a data table employs the PMT function with different loan amounts and interest rates to calculate the affordable amount on a home mortgage loan. Experimenting with different values to observe the corresponding variation in results is a common task in data analysis.
Overview
In Microsoft Excel, data tables are part of a suite of commands known as WhatIf analysis tools. When you construct and analyze data tables, you are doing whatif analysis.
Whatif analysis is the process of changing the values in cells to see how those changes will affect the outcome of formulas on the worksheet. For example, you can use a data table to vary the interest rate and term length for a loan—to evaluate potential monthly payment amounts.
Types of whatif analysis
There are three types of whatif analysis tools in Excel: scenarios, data tables, and goalseek. Scenarios and data tables use sets of input values to calculates possible results. Goalseek is distinctly different, it uses a single result and calculates possible input values that would produce that result.
Like scenarios, data tables help you explore a set of possible outcomes. Unlike scenarios, data tables show you all the outcomes in one table on one worksheet. Using data tables makes it easy to examine a range of possibilities at a glance. Because you focus on only one or two variables, results are easy to read and share in tabular form.
A data table cannot accommodate more than two variables. If you want to analyze more than two variables, you should instead use scenarios. Although it is limited to only one or two variables (one for the row input cell and one for the column input cell), a data table can include as many different variable values as you want. A scenario can have a maximum of 32 different values, but you can create as many scenarios as you want.
Learn more in the article, Introduction to WhatIf Analysis.
Data table basics
Create either onevariable or twovariable data tables, depending on the number of variables and formulas that you need to test.
Onevariable data tables
Use a onevariable data table if you want to see how different values of one variable in one or more formulas will change the results of those formulas. For example, you can use a onevariable data table to see how different interest rates affect a monthly mortgage payment by using the PMT function. You enter the variable values in one column or row, and the outcomes are displayed in an adjacent column or row.
In the following illustration, cell D2 contains the payment formula, =PMT(B3/12,B4,B5), which refers to the input cell B3.
Twovariable data tables
Use a twovariable data table to see how different values of two variables in one formula will change the results of that formula. For example, you can use a twovariable data table to see how different combinations of interest rates and loan terms will affect a monthly mortgage payment.
In the following illustration, cell C2 contains the payment formula, =PMT(B3/12,B4,B5), which uses two input cells, B3 and B4.
Data table calculations
Whenever a worksheet recalculates, any data tables will also recalculate—even if there has been no change to the data. To speed up calculation of a worksheet that contains a data table, you can change the Calculation options to automatically recalculate the worksheet but not the data tables. To learn more, see the section Speed up calculation in a worksheet that contains data tables.
Create a onevariable data table
A onevariable data table contain its input values either in a single column (columnoriented), or across a row (roworiented). Any formula in a onevariable data table must refer to only one input cell.
Follow these steps:

Type the list of values that you want to substitute in the input cell—either down one column or across one row. Leave a few empty rows and columns on either side of the values.

Do one of the following:

If the data table is columnoriented (your variable values are in a column), type the formula in the cell one row above and one cell to the right of the column of values. This onevariable data table is columnoriented, and the formula is contained in cell D2.
If you want to examine the effects of various values on other formulas, enter the additional formulas in cells to the right of the first formula. 
If the data table is roworiented (your variable values are in a row), type the formula in the cell one column to the left of the first value and one cell below the row of values.
If you want to examine the effects of various values on other formulas, enter the additional formulas in cells below the first formula.


Select the range of cells that contains the formulas and values that you want to substitute. In the figure above, this range is C2:D5.

On the Data tab, click WhatIf Analysis > Data Table (in the Data Tools group or Forecast group of Excel 2016).

Do one of the following:

If the data table is columnoriented, enter the cell reference for the input cell in the Column input cell field. In the figure above, the input cell is B3.

If the data table is roworiented, enter the cell reference for the input cell in the Row input cell field.
Note: After you create your data table, you might want to change the format of the result cells. In the figure, the result cells are formatted as currency.

Add a formula to a onevariable data table
Formulas that are used in a onevariable data table must refer to the same input cell.
Follow these steps

Do either of these:

If the data table is columnoriented, enter the new formula in a blank cell to the right of an existing formula in the top row of the data table.

If the data table is roworiented, enter the new formula in a empty cell below an existing formula in the first column of the data table.


Select the range of cells that contains the data table and the new formula.

On the Data tab, click WhatIf Analysis > Data Table (in the Data Tools group or Forecast group of Excel 2016).

Do either of the following:

If the data table is columnoriented, enter the cell reference for the input cell in the Column input cell box.

If the data table is roworiented, enter the cell reference for the input cell in the Row input cell box.

Create a twovariable data table
A twovariable data table uses a formula that contains two lists of input values. The formula must refer to two different input cells.
Follow these steps:

In a cell on the worksheet, enter the formula that refers to the two input cells.
In the following example—in which the formula starting values are entered in cells B3, B4, and B5, you type the formula =PMT(B3/12,B4,B5) in cell C2.

Type one list of input values in the same column, below the formula.
In this case, type the different interest rates in cells C3, C4, and C5.

Enter the second list in the same row as the formula—to its right.
Type the loan terms (in months) in cells D2 and E2.

Select the range of cells that contains the formula (C2), both the row and column of values (C3:C5 and D2:E2), and the cells in which you want the calculated values (D3:E5).
In this case, select the range C2:E5.

On the Data tab, in the Data Tools group or Forecast group (in Excel 2016), click WhatIf Analysis > Data Table (in the Data Tools group or Forecast group of Excel 2016).

In the Row input cell field, enter the reference to the input cell for the input values in the row.
Type cell B4 in the Row input cell box. 
In the Column input cell field, enter the reference to the input cell for the input values in the column.
Type B3 in the Column input cell box. 
Click OK.
Example of a twovariable data table
A twovariable data table can show how different combinations of interest rates and loan terms will affect a monthly mortgage payment. In the figure here, cell C2 contains the payment formula, =PMT(B3/12,B4,B5), which uses two input cells, B3 and B4.
Speed up calculation on a worksheet that contains data tables
When you set this calculation option, no datatable calculations occur when a recalculation is done on the entire workbook. To manually recalculate your data table, select its formulas and then press F9.
Follow these steps to improve calculation performance:

Do either of the following:

In Excel 2007, click the Microsoft Office Button , click Excel Options, and then click the Formulas category.

In all other versions, click File > Options > Formulas.


In the Calculation options section, under Calculate, click Automatic except for data tables.
Tip: Optionally, on the Formulas tab, click the arrow on Calculation Options, then click Automatic Except Data Tables (in the Calculation group).
What next?
You can use a few other Excel tools to perform whatif analysis if you have specific goals or larger sets of variable data.
Goal Seek
If you know the result to expect from a formula, but don't know precisely what input value the formula needs to get that result, use the GoalSeek feature. See the article Use Goal Seek to find the result you want by adjusting an input value.
Excel Solver
You can use the Excel Solver addin to find the optimal value for a set of input variables. Solver works with a group of cells (called decision variables, or simply variable cells) that are used in computing the formulas in the objective and constraint cells. Solver adjusts the values in the decision variable cells to satisfy the limits on constraint cells and produce the result you want for the objective cell. Learn more in this article: Define and solve a problem by using Solver.
Need more help?
You can always ask an expert in the Excel Tech Community, get support in the Answers community, or suggest a new feature or improvement on Excel User Voice.