---
title: "Numbers, percentages, and dates"
source: 18F Guides
source_url: https://github.com/18F/guides
licence: CC0-1.0
domain: engineering
subdomain: 18f-guides
date_added: 2026-04-25
---

## Numbers

Generally speaking, we follow the guidelines outlined in the [AP Stylebook](https://www.apstylebook.com/). In body copy, we prefer to spell out numbers *one* through *nine*, and use numerals for numbers 10 and greater. This is true of ordinal numbers, as well. Spell out *first* to *ninth*, and capture *10th* or greater with numerals.

Sometimes the government writes about very large numbers: millions, billions, even trillions. We express these numbers with a numeral and a word. For example, *1.6 million people*. When referring to amounts of money in cents or greater than $1 million, we use numerals followed by words: *5 cents* or *$2.7 million*. For amounts of money less than $1 million, we use the dollar sign: *$17*.

In titles, subheadings, and interface labels, we use numerals instead of spelling out numbers. For example, *10 digital tech leaders you should know now* or *6 ways to incorporate plain-language strategies*. We do this to promote ease of reading and scannability — in titles and headings, it’s easier for readers to scan numerals than it is for them to scan written-out numbers.

### Ranges

For ranges of numbers, see [Punctuation > Dashes]({{ "/content-guide/our-style/punctuation/#dashes" | url }}).

## Percentages

In keeping with AP style, we spell out *percent* in most cases, with a few exceptions. We use the percent sign (%) in these circumstances:

* **Tables and in technical or scientific writing**. For example: *60% of participants reported experiencing negative side effects*.
* **Headings and subheadings**. For example: *Candidate Woof takes 7% lead in the election for best dog*.
* **Interface labels**
* **Captions and infographics**

We choose to use the percent sign in these cases to improve content’s scannability, allowing readers to digest the content more quickly.


## Dates

To avoid confusion, we spell out specific dates such as "October 22, 2005," rather than abbreviating the month or using numbers as in "10/22/2005." Use the full, four-digit year. For informal writing, it's okay to use an abbreviated form. For example, *We're thankful web design isn't stuck in the '90s.*
