This article looks at the optimal line length for your body copy, the best unit for setting the width, and how many characters should be presented per line.
The optimal line length for body copy is considered to be 50-70 characters per line.
But how could we convert 50-75 characters into a measurement that could be used to define container widths?
This is hard to answer, as different content can affect how many characters appear per line.
I decided to do an experiment with four well-known texts:
- Source 1: "De Finibus Bonorum et Malorum" by Cicero
- Source 2: "Emma" by Jane Austen
- Source 3: "Metamorphosis" Franz Kafka
- Source 4: Lorem Ipsum
I took ten lines of text from each of these different examples, and then measured how many characters appeared per line at a range of different "em" widths.
Below is a table of the results, including an overall average across all five example texts.
| Width | Source 1 | Source 2 | Source 3 | Source 4 | Av |
|---|---|---|---|---|---|
| 35 em | 794 | 765 | 777 | 766 | 77.6 |
| 34 em | 757 | 739 | 745 | 741 | 74.6 |
| 33 em | 720 | 712 | 745 | 723 | 72.5 |
| 32 em | 720 | 692 | 708 | 710 | 70.8 |
| 31 em | 692 | 672 | 676 | 674 | 67.9 |
| 30 em | 682 | 664 | 651 | 637 | 65.9 |
| 29 em | 629 | 611 | 651 | 637 | 63.2 |
| 28 em | 603 | 600 | 601 | 605 | 60.2 |
| 27 em | 587 | 585 | 591 | 568 | 58.3 |
| 26 em | 572 | 546 | 573 | 561 | 56.3 |
| 25 em | 525 | 536 | 558 | 551 | 54.3 |
| 24 em | 510 | 518 | 513 | 511 | 51.3 |
| 23 em | 500 | 480 | 498 | 511 | 49.7 |
As you can see, the averages suggest that your container should be:
- A minimun of
23em- which has an average of 49.7 characters per line - A maximum of
35em- which has an average of 77.6 characters per line