How to Add Error Bars in Excel – Step-by-Step Guide

Do you want to visualize the variability and uncertainty in your Excel chart data? Error bars are an excellent way to quantify and display the potential error or range of confidence in your data points. This comprehensive guide will teach you everything you need to know about inserting and customizing error bars for your Excel charts.

Introduction to Using Error Bars

Error bars (also called uncertainty bars) indicate the degree of uncertainty or potential error in measurement data on a chart. They provide a graphical representation of the variability or precision in your data by showing a range rather than just a single data point.

Key reasons to use error bars include:

• Quantifying the amount of uncertainty, variability, noise, or potential error in your measurements
• Graphically representing the confidence intervals or potential spread of data points
• Visually comparing variability between different data sets more easily
• Assessing significance when looking at whether data point differences are within expected error margins
• Communicating measurement precision and accuracy more clearly

In Excel, adding error bars is straightforward for both standard and customized options. This guide will walk you through all the key steps including:

• Inserting standard error bars
• Creating custom error bar values
• Adding error bars for individual data points
• Using horizontal and secondary axis error bars
• Customizing error bar styles and display
• Modifying and deleting error bars
• Comparing error bars vs other options like data tables and trendlines

Follow along below and you’ll have beautifully formatted, informative error bars enhancing your Excel charts in no time!

Inserting Standard Error Bars

The fastest way to add error bars is to use Excel’s default options that automatically calculate error bar values based on your data. Here are the steps:

1. Select the data series in your chart that you want to add error bars to
2. Go to the Layout tab and click the Error Bars button
3. Choose one of the default error bar options:
   • Standard Error: displays error amount based on standard error of the mean
   • Standard Deviation: uses one standard deviation as the error value
   • Percentage: sets error bars at a percent of each data point value
   • Custom: specify your own +/- error amounts
4. The corresponding vertical error bars will now show on your data points!

The exact error values are automatically calculated by Excel based on your data set. Standard error and standard deviation are common statistical representations for variability ranges, while percentage allows you to indicate potential percentage-based variability.

For example, 5% error bars on a data point of 100 would display bars of +/- 5 indicating a potential range of 95 to 105 containing the true mean.

Custom allows fully manual error amounts if you know specific potential high/low ranges for your data points, while the other options dynamically update if your data changes.

Pro Tip: Right click on your chart and use the “Select Data” option to edit your data range and watch the error bar values recalculate automatically!

Creating Custom Error Bars

While Excel’s standard options cover many use cases, you may want to create custom error bars that meet specific needs. A few options for custom error bars include:

Error Bar Formulas

Use formulas that combine cell references and functions like MIN(), MAX() and STDEV() to fully customize error bar amounts dynamically based on your data set.

For example if your data was in cells A2:A100, your upper and lower error bar formulas could be:

Lower error = AVERAGE(A2:A100) - STDEV(A2:A100)
Upper error = AVERAGE(A2:A100) + STDEV(A2:A100)

This would calculate dynamic error amounts by taking the average (mean) and adding/subtracting the standard deviation range based on your actual data distribution.

High-Low Lines

If you have data with definitive ranges or confidence intervals, consider using high-low lines instead of error bars. These work just like error bars, but without bar caps or width customization options.

For example, adding high-low lines from a data low of 5 to a high of 10 would indicate your range of expectation for that measurement’s true value.

Individual Data Point Bars

You can also add larger or smaller error bars for certain data points by adjusting the error value formulas or custom inputs accordingly. This lets you indicate relative confidence between measurements on the same chart.

For example, data point 1 could have small +/- 5 error bars while data point 2 has wider +/- 50 bars on the same chart indicating lower measurement precision.

Adding Horizontal & Secondary Axis Error Bars

The examples above focus on vertical error bars, which are likely appropriate for most single-axis column, bar and scatter charts. However, there are options for horizontal and secondary axis error bars as well.

Horizontal Error Bars

Best practice is to use horizontal error bars ONLY for horizontal/column bar charts, where the independent variable axis and data point bars are horizontal rather than vertical.

The process is the same, just choose the Layout > Error Bars dropdown and select your desired option. This will overlay horizontal error bars on your existing horizontal columns or bars.

Secondary Axis

For more advanced “combo” charts with two vertical axes, you can add a second set of error bars tied to the secondary axis measurements. After adding the first set per the steps above, right click on the secondary data series and choose “Format Data Series”. Go to “Y error bars” to insert bars for just that axis.

This lets you include error bars for two totally different data types, scaled independently on left vs right axes. For example temperature on the left axis and humidity on the right, each with their own error bars.

Customizing Your Error Bars

One benefit of error bars in Excel is extensive formatting options to tailor their exact look and display to your needs. Follow the guidelines below to stylize your charts just the way you want them.

Formatting Error Bars

Once inserted, you can format error bars independently from the data series itself. Right click, choose “Format Error Bars” and use the options to set:

• Line Color & Style: Make bars black, matching data color, dotted lines, etc.
• Line Width: Thicker or thinner based on chart size & granularity
• End Style Cap: Choose rounded, square or no caps on bar ends
• Direction: Flip between vertical and horizontal as needed
• Positive/Negative Error Amounts: Show both ends symmetric or just high/low

Display & Layout Options

More visual customizations are available on the “Format Data Series” pane including:

• Percentage vs Fixed Value Display: Show static error amounts or dynamic % based on values
• Error Bar Position: Overlap, gap distance, offset and anchor points to data vs axis
• Error Bar Border: Add border color and weight for further distinction

Don’t be afraid to experiment with different visual styles, including hiding then unhiding bars to instantly compare view with and without error visualization!

Modifying & Deleting Error Bars

As the last piece of working with error bars, you need options for editing and removing them as data changes occur over time after initial insertion.

Modifying Error Bars

Easy options for modifying error bar values and styles include:

• Edit Values Directly: Click on the error bar in your chart and type in new custom amounts
• Change Cell Referenced Ranges: Expand your data rows/cols to include new points
• Alter Formulas: Tweak cell references, functions, operators to recalculate amounts
• Standard Error Bar Updates: Data changes automatically update amounts

Deleting Error Bars

Delete unneeded error bars using:

• Layout Tab > Error Bars > No Error Bars
• Right click the error bars > Clear
• OR Delete after clicking the error bars

This will cleanly remove the bars themselves without deleting or modifying any chart data.

Error Bars vs Other Options

While error bars are perfect for quantifying variability, other options like data tables and trendlines may work better depending on your analysis needs.

Error Bars vs Data Tables

Data tables display the actual numeric data values, while error bars illustrate their degree of variability visually. Use both in tandem for the clearest statistical reporting!

Error Bands vs Bars

Error bands are similar to error bars but shade an entire range/confidence interval for your data rather than just showing discrete low-high amounts. Useful when you have a suspected range but lack precise variance data.

Trendlines Instead

If assessing the overall trend rather than variability for each data point, consider using trendlines connecting the means rather than cluttering your chart with too many error bars.

Evaluate how audiences will use your Excel charts when deciding between bars, tables, lines, bands, to clearly communicate insights!

Helpful Error Bar Tips & Tricks

These tips will help you work with error bars more quickly and efficiently:

• Show/Hide Error Bars: Instantly toggle on and off under the Layout tab to compare views
• Freeze First Bar: Keep the first series’ error bars static while others change for reference comparison
• Add Reference Annotations: Use text boxes with arrows to explain specific error bars
• Troubleshooting Checks: If a series is missing error bars, check data/formula inputs and chart type best practices

Expand Your Error Bar Skills

You should now have a strong grasp of inserting, customizing, formatting, and modifying error bars within your Excel charts!

To practice and build confidence, download the bonus Error Bars Workbook PDF guide with sample data and use cases by clicking here (link to workbook PDF).

Check out more tips for visualizing data with Excel charts including:

• Formatting Data Points for Focus & Emphasis
• Choosing the Best Excel Chart Type
• Trendlines & Forecasting
• Heatmaps, Histograms & Multivariate Analysis

Now put your error bar skills to work in enhancing your own data analysis reports and dashboards in Excel!