Keep headers as short as possible; the design of the data table should be focused around the data itself, and long header labels can occupy a lot of visual space.

Headers

The most common label used in tables is the unit of measurement for the data; often, it’s repeated along with every single data point. Instead of repeating the label, only include it with the first data point in each column.

Units

It might sound like conventional wisdom, but giving your data table a clear and succinct title is as important as any other design decision you make. With a good title, tables are portable: they can be used in a number of different contexts, as well as cited from external sources.

Title

Using colors to provide organizational context or added meaning increases the likelihood of misinterpretation or error. Tables should be Monochromatic, with graphical elements like , and .

Backgrounds

When deciding how to style the graphic elements of a table, the goal should always be to reduce the table’s footprint without losing structural fidelity. One of the ways you can accomplish this is by using as little “ink” as possible — that is, whenever possible, choose not to style an element.

As little ink as possible

Oldstyle and lining figures look nice in sentences, where they better match the size and spacing of Lower-Case letters. Lining figures are more uniform, and reinforce the Grid-Like structure of the table. Tabular figures, on the other hand, are all Identically-Sized, so that columns of numbers line up properly.

Know your numerals

Horizontal rules allow you to significantly reduce the vertical space occupied by long tables. Rules should be extremely light to not interfere with quick scanning. One Unsubstantiated opinion is that zebra Striping is bad.

Rules

Fivethirtyeight set their numerical data in a Typeface called Decima Mono. The Typeface is specifically designed to fit lots of data in a small space. Special thanks to Edward Tutte for his Insightful writing on design.

A technical note on using tabular lining figures

One easy way to keep your tables properly aligned is to keep the same number of significant figures — usually the number of digits after the decimal — consistent within each column. Significant figures is a whole rabbit hole of a topic, so I’ll keep my advice here brief: the fewer sig figs you can get by with, the better.

Consistent Significant Figures = Better alignment

Providing labels to accompany your data is crucial. These pieces of accompanying context allow a data table to be read by a wider audience, in a broader set of circumstances.

Fewer, Clearer Labels

Numerical data is read Right-To-Left; that is, we compare numbers by looking at their ones digit, then their tens, then their hundreds. Tables should keep numerical data Right-Aligned; textual data is read from Left-To-Right. If two entries start with the same letter, the second letter is used, and so on. Headers, generally, should carry whatever alignment their data has.

Alignment Matters

After being the bread and butter of the web for most of its early history, tables were cast aside by many designers for newer, trendier layouts. But while they might be making fewer appearances on…