Data Tables (What-If) in Excel - Step-by-Step Guide

Introduction

Data Tables in Excel help you see how changing one or two numbers affects your results. This is useful when you want to test different scenarios without changing your formulas manually.

When you want to check how different loan interest rates affect monthly payments.

When you want to see how changing the price and quantity sold affects total revenue.

When you want to analyze how different investment returns impact your savings over time.

When you want to compare outcomes for different sales commission rates.

When you want to quickly test multiple input values to find the best option.

Steps

Step 1: Set up your formula that depends on input values

- Worksheet cells

You have a formula ready that uses one or two input cells for calculation

Step 2: List the input values you want to test

- Cells in a row or column next to your formula

You have a list of different input numbers arranged horizontally or vertically

Step 3: Select the range including the formula cell and the input values

- Worksheet cells covering formula and input values

The range is highlighted for creating the data table

Step 4: Click the Data tab, then click What-If Analysis, and select Data Table

- Excel ribbon on the Data tab

The Data Table dialog box opens

Step 5: Enter the input cell reference for Row input cell or Column input cell depending on your input layout

- Data Table dialog box

Excel knows which cell to change for each input value to recalculate the formula

Step 6: Click OK

- Data Table dialog box

Excel fills the table with results for each input value, showing how the formula output changes

Before vs After

Before

A formula calculates monthly payment based on interest rate in cell B1. Interest rates 3%, 4%, 5% are listed in cells C2, D2, E2.

After

Data Table fills cells C3, D3, E3 with monthly payment results for each interest rate, showing how payment changes.

Settings Reference

Row input cell

📍 Data Table dialog box

Specifies the cell whose value changes across the row input values

Default: None

Column input cell

📍 Data Table dialog box

Specifies the cell whose value changes down the column input values

Default: None

Common Mistakes

Not selecting the entire range including formula and input values before creating the Data Table

Excel needs the full range to fill results correctly; missing cells cause errors or incomplete tables

Always highlight the formula cell plus all input value cells before starting the Data Table

Entering wrong cell reference in Row input cell or Column input cell

If the input cell does not match the formula input, results will be incorrect or unchanged

Make sure to select the exact cell that the formula uses as input for the row or column input

Trying to use Data Tables with formulas that have multiple input cells without setting both row and column input cells

Data Tables can only handle one or two input cells; more inputs require other tools

Use one-variable Data Table for one input cell or two-variable Data Table for two input cells only

Summary

Data Tables let you test how changing inputs affects your formula results quickly.

You set up input values in rows or columns and link them to the formula input cells.

Remember to select the full range and specify correct input cells for accurate results.