The "Under 10 Rule" for Bold

Applying the Under 10 Rule for Bold is a simple way to make sure you don’t use bold too much. The two parts of the rule are:

  • Never bold more than 10% of your total text
  • Avoid bolding more than 10 words in a row

So, if you’ve got an e-mail/article of 500 words, no more than 50 words should be in bold – and no more than 10 words in a row, such as an entire sentence.

Why do we need the rule?

Bold tends to be a tool that is misused. People either don’t use it at all, or they use it too much. Very few people know how to get the balance right.

Why do we use bold at all?

Whenever we see a block of text, we tend not to read every single word unless it is a novel. Instead, we skim over looking for key information. In the absence of any additional formatting, we look for interesting words and phrases, to try and understand the key message.

The English Language (and most major languages) are constructed in a way that the more frequent words that we use are shorter (of, and, I, we, the) whereas the words we use less often tend to be longer (reservation, procrastinate, interoperability). This means that we already tend to focus on longer words, because they are more likely to contain meaning.

Text in bold (and other formatting techniques) forces you to stop skimming, due to the change in text style. However, if you bold too much, it loses its attention-grabbing ability.

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