Clarity · hard · v4.6.1

CLR-03

Use short sentences. Aim for 15-20 words per sentence. Sentences over 25 words should almost always be split.

Pass example

Your order shipped. It should arrive by Friday.

Fail example

We wanted to let you know that the order you placed has been shipped and based on current estimates it should be arriving to you by Friday of this week.

Relevant content types

Weighted in these moments

This standard behaves differently depending on the reader's moment. Moment-aware evaluation picks one of these adjustments when the moment matches.

  • first_encounter — emphasize
    Keep sentences short — cognitive load is highest on first use.
  • task_execution — emphasize
    Keep helper text short — users are mid-task, not reading.
  • confirmation — relax
    Brevity trumps sentence structure rules in success states.
  • destructive_action Destructive — relax
    Longer sentences are fine when explaining irreversible consequences.
  • interruption — emphasize
    Interruptions must justify themselves in as few words as possible.
  • wayfinding — suppress
    Navigation labels are fragments, not sentences. Length rules don't apply.

Example pairs

Concrete before/after pairs observed in public style guides, each with inline attribution. See /sources for the full source list and licensing.

  • browsing_discovery · long_form_copyOGL-3.0

    Not this. When you change your password you will be signed out of all devices and will need to sign back in on each one using your new password within the next 24 hours.

    But this. Changing your password signs you out everywhere. Sign back in with the new password within 24 hours.

    GOV.UK target: ≤25 words per sentence. Split at natural consequence boundaries. — GOV.UK Style Guide · Sentence length

Sources

Style guides that shaped this standard. Each is listed on /sources with its license and opt-out path.

  • GOV.UK Style Guide
  • Microsoft Writing Style Guide

Version history

  1. v4.6.1 · 2026-04-23

    Per-standard version tracking introduced. Every standard starts at the library version current at introduction; bump per-standard when the rule text, examples, or content_type_notes change.

Related standards

Other standards in the Clarity category.

  • CLR-01 — Use plain language. Avoid jargon, technical terms, or insider language unless the audience requires it.
  • CLR-02 — Lead with the most important information. Put the action or outcome first.
  • CLR-04 — One idea per sentence. Don't chain multiple concepts together.
  • CLR-05 — Avoid confusing double negatives that make the reader work to parse the meaning. Constructions like 'not irreversible' or 'not uncommon' should be rewritten as direct statements. Natural phrasing like 'can't proceed without' is acceptable when it reads clearly.

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