---
source: https://iinventedlight.com/library/notes/plain-language-must-not-shall.md
title: "Use must for requirements instead of shall"
license: CC-BY-4.0
license_url: https://creativecommons.org/licenses/by/4.0/
source_license: "US government work, public domain; original synthesis in our own words"
attribution: "Summary by iinventedlight (AI-assisted). Sources: GSA / PlainLanguage.gov archive, Use “must” to indicate requirements; GSA / PlainLanguage.gov archive, Shall and must."
author: "iinventedlight (synthesis of cited sources); text drafted with AI assistance"
date: 2026-11-05
status: published
checked_on: 2026-11-05
as_of: 2026-11-05
confidence: high
untested: "Editorial checklist only; not tested with readers. Sources fetched and evidence checked."
category: coverage-gaps
topic_area: "write-comm: requirement wording for official correspondence"
tags: writing, plain-language, communication, must-not-shall
sources:
  - id: S1
    title: "Use “must” to indicate requirements"
    publisher: "GSA / PlainLanguage.gov archive"
    url: https://raw.githubusercontent.com/GSA/plainlanguage.gov/main/_pages/guidelines/conversational/use-must-to-indicate-requirements.md
    accessed: 2026-11-05
    license: "US government work, public domain"
  - id: S2
    title: "Shall and must"
    publisher: "GSA / PlainLanguage.gov archive"
    url: https://raw.githubusercontent.com/GSA/plainlanguage.gov/main/_pages/guidelines/conversational/shall-and-must.md
    accessed: 2026-11-05
    license: "US government work, public domain"
---
# Use must for requirements instead of shall

Use must not shall to impose requirements. [S2]
Besides being outdated, shall is imprecise. [S1]
It can indicate either an obligation or a prediction. [S1]
Dropping shall is a major step in making your writing more user-friendly. [S1]
Many agencies already use the word must to convey obligations. [S1]

## Checklist
1. [ ] Use must to convey obligations. [S1]
2. [ ] Do not use shall to impose requirements. [S2]
3. [ ] Remember that shall can indicate either an obligation or a prediction. [S1]
4. [ ] Nobody uses shall in common speech. [S2]
5. [ ] Dropping shall makes your writing more user-friendly. [S1]

**Done when:** must conveys obligations. [S1] Dropping shall makes your writing more user-friendly. [S1]

## Claims
- id: C1
  claim: Use must rather than shall for requirements.
  source: S2
  evidence: "Use \"must\" not \"shall\" to impose requirements."
- id: C2
  claim: Shall is imprecise as well as outdated.
  source: S1
  evidence: "Besides being outdated, \"shall\" is imprecise."
- id: C3
  claim: Shall can mean obligation or prediction.
  source: S1
  evidence: "It can indicate either an obligation or a prediction."
- id: C4
  claim: Many agencies already use must for obligations.
  source: S1
  evidence: "Many agencies already use the word \"must\" to convey obligations."
- id: C5
  claim: Nobody uses shall in common speech.
  source: S2
  evidence: "Third, nobody uses \"shall\" in common speech."

## Sources
- [S1] Use “must” to indicate requirements. GSA / PlainLanguage.gov archive. https://raw.githubusercontent.com/GSA/plainlanguage.gov/main/_pages/guidelines/conversational/use-must-to-indicate-requirements.md . License: US government work, public domain. Accessed 2026-11-05.
- [S2] Shall and must. GSA / PlainLanguage.gov archive. https://raw.githubusercontent.com/GSA/plainlanguage.gov/main/_pages/guidelines/conversational/shall-and-must.md . License: US government work, public domain. Accessed 2026-11-05.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted).