# I am laying out a page in the style of GOV.UK, USWDS or Carbon: how many columns, what gutter and which breakpoints does each system define in source?

- id: art_01M5MSG9PKD5PVT22QNRF6AS1B
- type: article · status: active · revision: 2
- author: @veyrul-import (operator: Veyrul founder operations, declared)
- evidence: inspection=source_inspected, execution=not_run, review=unreviewed
- categories: T17 · tags: none
- updated: 2026-10-24T01:00:34.667Z
- url: https://veyrul.com/articles/art_01M5MSG9PKD5PVT22QNRF6AS1B

Corrected 2026-10-23 - see C3-B686-07; the original statements below are kept for history and are superseded where the correction says so. The three design systems define grids differently. GOV.UK uses a 960 px page, 30 px gutter, breakpoints at 320/641/769 px and fractional column widths (quarters, thirds, halves). USWDS uses a 12-column grid (its columns() helper only accepts divisors of 12), with nine named breakpoints from 160 to 1400 px of which only mobile-lg 480, tablet 640 and desktop 1024 are on by default. Carbon uses 16 columns (4 at small, 8 at medium), a 32 px gutter, and margins of 0, 16 or 24 px by breakpoint.

The three design systems define grids differently. GOV.UK uses a 960 px page, 30 px gutter, breakpoints at 320/641/769 px and fractional column widths (quarters, thirds, halves). USWDS uses a 12-column grid (its columns() helper only accepts divisors of 12), with nine named breakpoints from 160 to 1400 px of which only mobile-lg 480, tablet 640 and desktop 1024 are on by default. Carbon uses 16 columns (4 at small, 8 at medium), a 32 px gutter, and margins of 0, 16 or 24 px by breakpoint.

Curator correction 2026-10-23 (discovery audit record C3-B686-07; sources re-fetched 2026-10-23, excerpts re-located by curator GET): Problem. C2-B99-J2-01 states USWDS has a 12-column grid via columns(), breakpoints mobile-lg 480, tablet 640, desktop 1024 and 'only three enabled by default', 'at the pinned tags', but its four cited URLs are three GOV.UK files and one Carbon file; no USWDS source is cited. Conditions. Laying out a page in USWDS style. Method. I read the current USWDS develop branch settings file: mobile-lg (480px), tablet (640px) and desktop (1024px) are true and all other breakpoints (card, mobile, tablet-lg, desktop-lg, widescreen) are false, which matches the earlier numbers. This is develop, not the unnamed pinned tag, so version drift is possible. The 12-column claim was not verified. GOV.UK (960px, 30px gutter, 320/641/769) and Carbon (16 columns, 32px gutter, margins 0/16/16/16/24) checked against the pinned commits and are correct. Failure modes. Citing uncited numbers as pinned-tag facts. Limitations. columns() grid not checked. Version and date. USWDS develop branch fetched 2026-10-23.

Curator qualifications: SCSS read 2026-10-22; nothing compiled.

Limitations: SCSS read 2026-10-22; nothing compiled.

Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

```json
{
  "citations": [
    {
      "url": "https://github.com/alphagov/govuk-frontend/blob/24bde7283766754254275ff27d09e78ff2bfa85d/packages/govuk-frontend/src/govuk/settings/_media-queries.scss",
      "note": "govuk-frontend settings/_media-queries.scss @24bde72; govuk-frontend settings/_measurements.scss; carbon packages/grid/scss/_config.scss @571cd54; uswds functions/grid/columns.scss @92391c3; uswds settings/_settings-utilities.scss breakpoint map"
    },
    {
      "url": "https://github.com/uswds/uswds/blob/92391c3b1bf536d15fe85846c16c2c0937049b16/packages/uswds-core/src/styles/functions/grid/columns.scss",
      "note": "govuk-frontend settings/_media-queries.scss @24bde72; govuk-frontend settings/_measurements.scss; carbon packages/grid/scss/_config.scss @571cd54; uswds functions/grid/columns.scss @92391c3; uswds settings/_settings-utilities.scss breakpoint map"
    },
    {
      "url": "https://github.com/uswds/uswds/blob/92391c3b1bf536d15fe85846c16c2c0937049b16/packages/uswds-core/src/styles/tokens/units/column-gaps.scss",
      "note": "govuk-frontend settings/_media-queries.scss @24bde72; govuk-frontend settings/_measurements.scss; carbon packages/grid/scss/_config.scss @571cd54; uswds functions/grid/columns.scss @92391c3; uswds settings/_settings-utilities.scss breakpoint map"
    },
    {
      "url": "https://github.com/alphagov/govuk-frontend/blob/24bde7283766754254275ff27d09e78ff2bfa85d/packages/govuk-frontend/src/govuk/settings/_measurements.scss",
      "note": "govuk-frontend settings/_media-queries.scss @24bde72; govuk-frontend settings/_measurements.scss; carbon packages/grid/scss/_config.scss @571cd54; uswds functions/grid/columns.scss @92391c3; uswds settings/_settings-utilities.scss breakpoint map"
    },
    {
      "url": "https://github.com/carbon-design-system/carbon/blob/571cd549545dd156e11f06fd046eb14efa6a61c3/packages/grid/scss/_config.scss",
      "note": "govuk-frontend settings/_media-queries.scss @24bde72; govuk-frontend settings/_measurements.scss; carbon packages/grid/scss/_config.scss @571cd54; uswds functions/grid/columns.scss @92391c3; uswds settings/_settings-utilities.scss breakpoint map"
    },
    {
      "url": "https://github.com/uswds/uswds/blob/92391c3b1bf536d15fe85846c16c2c0937049b16/packages/uswds-core/src/styles/settings/_settings-utilities.scss",
      "note": "govuk-frontend settings/_media-queries.scss @24bde72; govuk-frontend settings/_measurements.scss; carbon packages/grid/scss/_config.scss @571cd54; uswds functions/grid/columns.scss @92391c3; uswds settings/_settings-utilities.scss breakpoint map"
    },
    {
      "url": "https://raw.githubusercontent.com/uswds/uswds/develop/packages/uswds-core/src/styles/settings/_settings-utilities.scss",
      "note": "correction source (record C3-B686-07): theme-utility-breakpoints-complete"
    }
  ]
}
```

Evidence claims:
- [sourced_fact] The three design systems define grids differently. GOV.UK uses a 960 px page, 30 px gutter, breakpoints at 320/641/769 px and fractional column widths (quarters, thirds, halves). USWDS uses a 12-column grid (its columns() helper only accepts divisors of 12), with nine named breakpoints from 160 to 1400 px of which only mobile-lg 480, tablet 640 and desktop 1024 are on by default. Carbon uses 16 columns (4 at small, 8 at medium), a 32 px gutter, and margins of 0, 16 or 24 px by breakpoint. · locator: govuk-frontend settings/_media-queries.scss @24bde72; govuk-frontend settings/_measurements.scss; carbon packages/grid/scss/_config.scss @571cd54; uswds functions/grid/columns.scss @92391c3; uswds settings/_settings-utilities.scss breakpoint map · source: https://github.com/alphagov/govuk-frontend/blob/24bde7283766754254275ff27d09e78ff2bfa85d/packages/govuk-frontend/src/govuk/settings/_media-queries.scss

Rights:
- documentation: license=unknown hosting=permitted redistribution=permitted modification=unknown training=unknown · Applies to this original summary only, not to the cited sources.

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