Ratio

The ratio helper keeps a box at a fixed aspect ratio whatever its width, which is perfect for media placeholders, thumbnails, galleries and banners. Pick ratio-1x1, ratio-4x3, ratio-16x9 or ratio-21x9, or set any ratio with the --ui-aspect-ratio variable.

1The four built-in ratios

ratio-1x1, ratio-4x3, ratio-16x9 and ratio-21x9 next to each other, filled with a plain div.

1:1

4:3

16:9

21:9

<div class="row g-3">
  <div class="col-6 col-md-3">
    <div class="ratio ratio-1x1">
      <div class="flex items-center justify-center bg-primary-subtle text-primary-emphasis border border-primary/30 rounded-md font-semibold">
        1:1
      </div>
    </div>
  </div>
  <div class="col-6 col-md-3">
    <div class="ratio ratio-4x3">
      <div class="flex items-center justify-center bg-primary-subtle text-primary-emphasis border border-primary/30 rounded-md font-semibold">
        4:3
      </div>
    </div>
  </div>
  <div class="col-6 col-md-3">
    <div class="ratio ratio-16x9">
      <div class="flex items-center justify-center bg-primary-subtle text-primary-emphasis border border-primary/30 rounded-md font-semibold">
        16:9
      </div>
    </div>
  </div>
  <div class="col-6 col-md-3">
    <div class="ratio ratio-21x9">
      <div class="flex items-center justify-center bg-primary-subtle text-primary-emphasis border border-primary/30 rounded-md font-semibold">
        21:9
      </div>
    </div>
  </div>
</div>

2Video placeholder

A 16:9 poster image with a centred play button, ready for a video player of your choice.

<div class="ratio ratio-16x9 rounded-md overflow-hidden" style="max-width:36rem">
  <div>
    <img src="../assets/img/wide-2.svg" alt="Video poster" class="w-full h-full object-cover">
    <button type="button" class="btn btn-light rounded-full absolute top-1/2 start-1/2 -translate-x-1/2 -translate-y-1/2 shadow-md" aria-label="Play video"><i class="bi bi-play-fill" aria-hidden="true"></i></button>
  </div>
</div>

3Square product thumbnails

ratio-1x1 with object-fit-cover gives every product the same tile, whatever the photo size.

Starter plan

Automation pack

Enterprise suite

Priority support

Business plan

Analytics add-on

<div class="row g-2">
  <div class="col-4 col-md-2">
    <div class="ratio ratio-1x1 rounded-md overflow-hidden border">
      <img src="../assets/img/product-1.svg" alt="Starter plan" class="object-cover">
    </div>
    <p class="small truncate mt-1 mb-0">Starter plan</p>
  </div>
  <div class="col-4 col-md-2">
    <div class="ratio ratio-1x1 rounded-md overflow-hidden border">
      <img src="../assets/img/product-6.svg" alt="Automation pack" class="object-cover">
    </div>
    <p class="small truncate mt-1 mb-0">Automation pack</p>
  </div>
  <div class="col-4 col-md-2">
    <div class="ratio ratio-1x1 rounded-md overflow-hidden border">
      <img src="../assets/img/product-4.svg" alt="Enterprise suite" class="object-cover">
    </div>
    <p class="small truncate mt-1 mb-0">Enterprise suite</p>
  </div>
  <div class="col-4 col-md-2">
    <div class="ratio ratio-1x1 rounded-md overflow-hidden border">
      <img src="../assets/img/product-7.svg" alt="Priority support" class="object-cover">
    </div>
    <p class="small truncate mt-1 mb-0">Priority support</p>
  </div>
  <div class="col-4 col-md-2">
    <div class="ratio ratio-1x1 rounded-md overflow-hidden border">
      <img src="../assets/img/product-3.svg" alt="Business plan" class="object-cover">
    </div>
    <p class="small truncate mt-1 mb-0">Business plan</p>
  </div>
  <div class="col-4 col-md-2">
    <div class="ratio ratio-1x1 rounded-md overflow-hidden border">
      <img src="../assets/img/product-5.svg" alt="Analytics add-on" class="object-cover">
    </div>
    <p class="small truncate mt-1 mb-0">Analytics add-on</p>
  </div>
</div>

4Cinematic hero banner

ratio-21x9 for a wide banner with a headline overlay.

Fewer meetings, more finished work

Start free, upgrade when you grow and cancel any time with one click.

<div class="ratio ratio-21x9 rounded-lg overflow-hidden">
  <div>
    <img src="https://images.unsplash.com/photo-1690264351371-b75a9a9bdbdd?auto=format&fit=crop&w=1600&h=700&q=70" alt="" class="w-full h-full object-cover">
    <div class="absolute bottom-0 start-0 p-4 md:p-6 text-white" style="background:rgba(0,0,0,.45)">
      <h3 class="h4 mb-1">Fewer meetings, more finished work</h3>
      <p class="small mb-0 hidden sm:block">Start free, upgrade when you grow and cancel any time with one click.</p>
    </div>
  </div>
</div>

5Map placeholder

A 4:3 box reserved for a map, showing the address until the map loads.

Aeroora Flow398 Hillcrest Road, Singapore

<div class="ratio ratio-4x3" style="max-width:24rem">
  <div class="flex flex-col items-center justify-center bg-surface-3 border rounded-md text-center p-4">
    <span class="text-4xl text-primary-ink"><i class="bi bi-geo-alt-fill" aria-hidden="true"></i></span><strong>Aeroora Flow</strong><span class="small text-muted">398 Hillcrest Road, Singapore</span>
  </div>
</div>

6Custom 3:2 photo

Any ratio works with the --ui-aspect-ratio variable: 2 / 3 = 66.67% for classic photo prints.

Looking back at a busy season — 3:2 · Seven automations every team should set up

<figure class="mb-0" style="max-width:28rem">
  <div class="ratio rounded-md overflow-hidden" style="--ui-aspect-ratio:66.67%">
    <img src="https://images.unsplash.com/photo-1702301266409-ed1bfe210971?auto=format&fit=crop&w=1200&h=800&q=70" alt="Looking back at a busy season" class="object-cover">
  </div>
  <figcaption class="small text-muted mt-1">3:2 &middot; Seven automations every team should set up</figcaption>
</figure>

7Portrait team cards

A 3:4 portrait ratio (133.33%) for team photos in cards.

Samir Carter

Customer Success

Mateo Alvarez

Frontend Engineer

Sofia Brennan

Customer Success

<div class="row g-3">
  <div class="col-6 col-md-4">
    <div class="card h-full">
      <div class="ratio card-img-top overflow-hidden" style="--ui-aspect-ratio:133.33%">
        <img src="https://images.unsplash.com/photo-1690264351371-b75a9a9bdbdd?auto=format&fit=crop&w=1200&h=800&q=70" alt="Samir Carter" class="object-cover">
      </div>
      <div class="card-body py-2">
        <h3 class="h6 mb-0">Samir Carter</h3>
        <p class="small text-muted mb-0">Customer Success</p>
      </div>
    </div>
  </div>
  <div class="col-6 col-md-4">
    <div class="card h-full">
      <div class="ratio card-img-top overflow-hidden" style="--ui-aspect-ratio:133.33%">
        <img src="https://images.unsplash.com/photo-1702301266409-ed1bfe210971?auto=format&fit=crop&w=1200&h=800&q=70" alt="Mateo Alvarez" class="object-cover">
      </div>
      <div class="card-body py-2">
        <h3 class="h6 mb-0">Mateo Alvarez</h3>
        <p class="small text-muted mb-0">Frontend Engineer</p>
      </div>
    </div>
  </div>
  <div class="col-6 col-md-4">
    <div class="card h-full">
      <div class="ratio card-img-top overflow-hidden" style="--ui-aspect-ratio:133.33%">
        <img src="https://images.unsplash.com/photo-1758691737124-05c5bffe46f0?auto=format&fit=crop&w=1200&h=800&q=70" alt="Sofia Brennan" class="object-cover">
      </div>
      <div class="card-body py-2">
        <h3 class="h6 mb-0">Sofia Brennan</h3>
        <p class="small text-muted mb-0">Customer Success</p>
      </div>
    </div>
  </div>
</div>

8Vertical stories

A 9:16 ratio (177.78%) for phone sized stories or short clips in a scrolling row.

Noah

Theo

Ruby

Kenji

<div class="flex gap-2 overflow-auto pb-1">
  <div class="shrink-0" style="width:7rem">
    <div class="ratio rounded-lg overflow-hidden" style="--ui-aspect-ratio:177.78%">
      <div>
        <img src="https://images.unsplash.com/photo-1742440710136-1976b1cad864?auto=format&fit=crop&w=1200&h=800&q=70" alt="Story by Noah Rossi" class="w-full h-full object-cover"><span class="absolute bottom-0 start-0 m-1 badge text-bg-dark">Noah</span>
      </div>
    </div>
  </div>
  <div class="shrink-0" style="width:7rem">
    <div class="ratio rounded-lg overflow-hidden" style="--ui-aspect-ratio:177.78%">
      <div>
        <img src="https://images.unsplash.com/photo-1690264351371-b75a9a9bdbdd?auto=format&fit=crop&w=1200&h=800&q=70" alt="Story by Theo Ashford" class="w-full h-full object-cover"><span class="absolute bottom-0 start-0 m-1 badge text-bg-dark">Theo</span>
      </div>
    </div>
  </div>
  <div class="shrink-0" style="width:7rem">
    <div class="ratio rounded-lg overflow-hidden" style="--ui-aspect-ratio:177.78%">
      <div>
        <img src="https://images.unsplash.com/photo-1531545514256-b1400bc00f31?auto=format&fit=crop&w=1200&h=800&q=70" alt="Story by Ruby Silva" class="w-full h-full object-cover"><span class="absolute bottom-0 start-0 m-1 badge text-bg-dark">Ruby</span>
      </div>
    </div>
  </div>
  <div class="shrink-0" style="width:7rem">
    <div class="ratio rounded-lg overflow-hidden" style="--ui-aspect-ratio:177.78%">
      <div>
        <img src="https://images.unsplash.com/photo-1690264421892-46e3af5c3455?auto=format&fit=crop&w=1200&h=800&q=70" alt="Story by Kenji Sato" class="w-full h-full object-cover"><span class="absolute bottom-0 start-0 m-1 badge text-bg-dark">Kenji</span>
      </div>
    </div>
  </div>
</div>

9Chart area

A 16:9 box that keeps a simple bar chart in proportion on every screen.

Monthly bookings

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

<div class="card" style="max-width:36rem">
  <div class="card-header small font-semibold">
    Monthly bookings
  </div>
  <div class="card-body">
    <div class="ratio ratio-16x9">
      <div class="flex items-end gap-2" role="img" aria-label="Bar chart of monthly bookings">
        <div class="flex-auto flex flex-col justify-end items-center h-full">
          <div class="w-full bg-primary rounded-t-md" style="height:49%">
          </div>
          <span class="small text-muted">Jan</span>
        </div>
        <div class="flex-auto flex flex-col justify-end items-center h-full">
          <div class="w-full bg-primary rounded-t-md" style="height:71%">
          </div>
          <span class="small text-muted">Feb</span>
        </div>
        <div class="flex-auto flex flex-col justify-end items-center h-full">
          <div class="w-full bg-primary rounded-t-md" style="height:39%">
          </div>
          <span class="small text-muted">Mar</span>
        </div>
        <div class="flex-auto flex flex-col justify-end items-center h-full">
          <div class="w-full bg-primary rounded-t-md" style="height:24%">
          </div>
          <span class="small text-muted">Apr</span>
        </div>
        <div class="flex-auto flex flex-col justify-end items-center h-full">
          <div class="w-full bg-primary rounded-t-md" style="height:81%">
          </div>
          <span class="small text-muted">May</span>
        </div>
        <div class="flex-auto flex flex-col justify-end items-center h-full">
          <div class="w-full bg-primary rounded-t-md" style="height:76%">
          </div>
          <span class="small text-muted">Jun</span>
        </div>
        <div class="flex-auto flex flex-col justify-end items-center h-full">
          <div class="w-full bg-primary rounded-t-md" style="height:52%">
          </div>
          <span class="small text-muted">Jul</span>
        </div>
        <div class="flex-auto flex flex-col justify-end items-center h-full">
          <div class="w-full bg-primary rounded-t-md" style="height:29%">
          </div>
          <span class="small text-muted">Aug</span>
        </div>
      </div>
    </div>
  </div>
</div>

10Blog card cover

ratio-16x9 as a card image keeps every post card in a grid the same height.

tips

How remote teams keep projects on track

Oct 4, 2026

<div class="card" style="max-width:22rem">
  <div class="ratio ratio-16x9 card-img-top overflow-hidden">
    <img src="https://images.unsplash.com/photo-1690264351371-b75a9a9bdbdd?auto=format&fit=crop&w=1200&h=800&q=70" alt="A practical guide to async work" class="object-cover">
  </div>
  <div class="card-body">
    <span class="badge text-bg-light border mb-2">tips</span>
    <h3 class="h6">How remote teams keep projects on track</h3>
    <p class="small text-muted mb-0">Oct 4, 2026</p>
  </div>
</div>

11Caption over a gradient

A 4:3 image with a gradient overlay so white caption text stays readable.

ValenciaTeam analytics

<div class="ratio ratio-4x3 rounded-lg overflow-hidden" style="max-width:24rem">
  <div>
    <img src="https://images.unsplash.com/photo-1690264421892-46e3af5c3455?auto=format&fit=crop&w=1200&h=800&q=70" alt="" class="w-full h-full object-cover">
    <div class="absolute bottom-0 w-full p-4 text-white" style="background:linear-gradient(transparent,rgba(0,0,0,.7))">
      <strong class="block">Valencia</strong><span class="small">Team analytics</span>
    </div>
  </div>
</div>

12Mixed ratio gallery

Combining 1:1, 4:3 and 16:9 tiles in one responsive grid.

<div class="row g-2">
  <div class="col-md-6">
    <div class="ratio ratio-4x3 rounded-md overflow-hidden">
      <img src="https://images.unsplash.com/photo-1758691737124-05c5bffe46f0?auto=format&fit=crop&w=1200&h=800&q=70" alt="Gallery photo 1" class="object-cover">
    </div>
  </div>
  <div class="col-md-6">
    <div class="row g-2">
      <div class="col-6">
        <div class="ratio ratio-1x1 rounded-md overflow-hidden">
          <img src="https://images.unsplash.com/photo-1522202176988-66273c2fd55f?auto=format&fit=crop&w=800&h=800&q=70" alt="Gallery photo 2" class="object-cover">
        </div>
      </div>
      <div class="col-6">
        <div class="ratio ratio-1x1 rounded-md overflow-hidden">
          <img src="https://images.unsplash.com/photo-1690264459911-6d68c747d8a7?auto=format&fit=crop&w=800&h=800&q=70" alt="Gallery photo 3" class="object-cover">
        </div>
      </div>
      <div class="col-12">
        <div class="ratio ratio-21x9 rounded-md overflow-hidden">
          <img src="https://images.unsplash.com/photo-1690264421892-46e3af5c3455?auto=format&fit=crop&w=1600&h=700&q=70" alt="Gallery photo 4" class="object-cover">
        </div>
      </div>
    </div>
  </div>
</div>

13Thumbnails in table cells

A small ratio-1x1 box keeps order line images square inside a table.

Image	Item	Price
	Analytics add-on	$12.00
	Priority support	$26.99
	Sales pipeline add-on	$20.00

<table class="table align-middle mb-0">
  <thead>
    <tr>
      <th scope="col"><span class="sr-only">Image</span></th>
      <th scope="col">Item</th>
      <th scope="col" class="text-end">Price</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td style="width:4rem"><div class="ratio ratio-1x1 rounded-md overflow-hidden"><img src="../assets/img/product-5.svg" alt="Analytics add-on" class="object-cover"></div></td>
      <td class="align-middle">Analytics add-on</td>
      <td class="align-middle text-end">$12.00</td>
    </tr>
    <tr>
      <td style="width:4rem"><div class="ratio ratio-1x1 rounded-md overflow-hidden"><img src="../assets/img/product-7.svg" alt="Priority support" class="object-cover"></div></td>
      <td class="align-middle">Priority support</td>
      <td class="align-middle text-end">$26.99</td>
    </tr>
    <tr>
      <td style="width:4rem"><div class="ratio ratio-1x1 rounded-md overflow-hidden"><img src="../assets/img/product-10.svg" alt="Sales pipeline add-on" class="object-cover"></div></td>
      <td class="align-middle">Sales pipeline add-on</td>
      <td class="align-middle text-end">$20.00</td>
    </tr>
  </tbody>
</table>

14Empty cover placeholder

A dashed 4:3 area that reserves space for an image that has not been chosen yet.

No cover image yet

<div class="ratio ratio-4x3" style="max-width:20rem">
  <div class="flex flex-col items-center justify-center border border-2 border-secondary/30 rounded-lg text-muted wt-border-dashed">
    <span class="text-3xl"><i class="bi bi-image-fill" aria-hidden="true"></i></span><span class="small">No cover image yet</span>
  </div>
</div>

15Colour swatches

Empty square ratios make perfect colour swatches for a style guide.

primary

secondary

success

info

warning

danger

<div class="row g-2">
  <div class="col-4 col-md-2">
    <div class="ratio ratio-1x1 rounded-lg bg-primary">
      <span class="sr-only">primary</span>
    </div>
    <p class="small text-center mt-1 mb-0">primary</p>
  </div>
  <div class="col-4 col-md-2">
    <div class="ratio ratio-1x1 rounded-lg bg-secondary">
      <span class="sr-only">secondary</span>
    </div>
    <p class="small text-center mt-1 mb-0">secondary</p>
  </div>
  <div class="col-4 col-md-2">
    <div class="ratio ratio-1x1 rounded-lg bg-success">
      <span class="sr-only">success</span>
    </div>
    <p class="small text-center mt-1 mb-0">success</p>
  </div>
  <div class="col-4 col-md-2">
    <div class="ratio ratio-1x1 rounded-lg bg-info">
      <span class="sr-only">info</span>
    </div>
    <p class="small text-center mt-1 mb-0">info</p>
  </div>
  <div class="col-4 col-md-2">
    <div class="ratio ratio-1x1 rounded-lg bg-warning">
      <span class="sr-only">warning</span>
    </div>
    <p class="small text-center mt-1 mb-0">warning</p>
  </div>
  <div class="col-4 col-md-2">
    <div class="ratio ratio-1x1 rounded-lg bg-danger">
      <span class="sr-only">danger</span>
    </div>
    <p class="small text-center mt-1 mb-0">danger</p>
  </div>
</div>

16Video thumbnails with badges

Duration and status badges positioned over 16:9 thumbnails.

2:39New

The real cost of switching between tools

14:47

Five things we learned this year

3:14

Writing status updates people actually read

<div class="row g-3">
  <div class="col-md-4">
    <div class="ratio ratio-16x9 rounded-md overflow-hidden">
      <div>
        <img src="https://images.unsplash.com/photo-1554902843-260acd0993f8?auto=format&fit=crop&w=1200&h=800&q=70" alt="" class="w-full h-full object-cover"><span class="absolute bottom-0 end-0 m-2 badge text-bg-dark">2:39</span><span class="absolute top-0 start-0 m-2 badge text-bg-danger">New</span>
      </div>
    </div>
    <p class="small font-semibold mt-1 mb-0">The real cost of switching between tools</p>
  </div>
  <div class="col-md-4">
    <div class="ratio ratio-16x9 rounded-md overflow-hidden">
      <div>
        <img src="https://images.unsplash.com/photo-1690264350953-79ef8acbd562?auto=format&fit=crop&w=1200&h=800&q=70" alt="" class="w-full h-full object-cover"><span class="absolute bottom-0 end-0 m-2 badge text-bg-dark">14:47</span>
      </div>
    </div>
    <p class="small font-semibold mt-1 mb-0">Five things we learned this year</p>
  </div>
  <div class="col-md-4">
    <div class="ratio ratio-16x9 rounded-md overflow-hidden">
      <div>
        <img src="https://images.unsplash.com/photo-1742440710136-1976b1cad864?auto=format&fit=crop&w=1200&h=800&q=70" alt="" class="w-full h-full object-cover"><span class="absolute bottom-0 end-0 m-2 badge text-bg-dark">3:14</span>
      </div>
    </div>
    <p class="small font-semibold mt-1 mb-0">Writing status updates people actually read</p>
  </div>
</div>

17Media list

Fixed width 4:3 thumbnails beside article titles in a reading list.

What our customers asked us most
Jun 19, 2026 · 4 min read
Our favourite tips for busy weeks
Aug 3, 2026 · 3 min read
What we learned shipping 200 releases
Dec 7, 2025 · 6 min read

<ul class="list-unstyled mb-0 vstack gap-4">
  <li class="flex gap-4"><div class="shrink-0" style="width:6rem"><div class="ratio ratio-4x3 rounded-md overflow-hidden"><img src="https://images.unsplash.com/photo-1531545514256-b1400bc00f31?auto=format&fit=crop&w=1200&h=800&q=70" alt="" class="object-cover"></div></div><div><h3 class="h6 mb-1">What our customers asked us most</h3><p class="small text-muted mb-0">Jun 19, 2026 &middot; 4 min read</p></div></li>
  <li class="flex gap-4"><div class="shrink-0" style="width:6rem"><div class="ratio ratio-4x3 rounded-md overflow-hidden"><img src="https://images.unsplash.com/photo-1690264421892-46e3af5c3455?auto=format&fit=crop&w=1200&h=800&q=70" alt="" class="object-cover"></div></div><div><h3 class="h6 mb-1">Our favourite tips for busy weeks</h3><p class="small text-muted mb-0">Aug 3, 2026 &middot; 3 min read</p></div></li>
  <li class="flex gap-4"><div class="shrink-0" style="width:6rem"><div class="ratio ratio-4x3 rounded-md overflow-hidden"><img src="https://images.unsplash.com/photo-1522202176988-66273c2fd55f?auto=format&fit=crop&w=1200&h=800&q=70" alt="" class="object-cover"></div></div><div><h3 class="h6 mb-1">What we learned shipping 200 releases</h3><p class="small text-muted mb-0">Dec 7, 2025 &middot; 6 min read</p></div></li>
</ul>

18Responsive ratio

A small custom class changes --ui-aspect-ratio per breakpoint: square on phones, 21:9 on tablets and up.

<div class="ratio hp-ratio-resp rounded-lg overflow-hidden">
  <img src="https://images.unsplash.com/photo-1690264459911-6d68c747d8a7?auto=format&fit=crop&w=1600&h=700&q=70" alt="Plan, build and launch in one place" class="object-cover">
</div>

19Round avatars

ratio-1x1 with rounded-circle keeps profile pictures perfectly round even when the source is not square.

Freya

Mia

Arjun

Finn

<div class="flex flex-wrap gap-4">
  <div class="text-center" style="width:5rem">
    <div class="ratio ratio-1x1 rounded-full overflow-hidden border border-2 border-primary">
      <img src="../assets/img/avatar-11.svg" alt="Freya Harlow" class="object-cover">
    </div>
    <span class="small block truncate mt-1">Freya</span>
  </div>
  <div class="text-center" style="width:5rem">
    <div class="ratio ratio-1x1 rounded-full overflow-hidden border border-2 border-primary">
      <img src="../assets/img/avatar-11.svg" alt="Mia Moreau" class="object-cover">
    </div>
    <span class="small block truncate mt-1">Mia</span>
  </div>
  <div class="text-center" style="width:5rem">
    <div class="ratio ratio-1x1 rounded-full overflow-hidden border border-2 border-primary">
      <img src="../assets/img/avatar-1.svg" alt="Arjun Larsen" class="object-cover">
    </div>
    <span class="small block truncate mt-1">Arjun</span>
  </div>
  <div class="text-center" style="width:5rem">
    <div class="ratio ratio-1x1 rounded-full overflow-hidden border border-2 border-primary">
      <img src="../assets/img/avatar-7.svg" alt="Finn Brennan" class="object-cover">
    </div>
    <span class="small block truncate mt-1">Finn</span>
  </div>
</div>

20Loading skeleton

A 16:9 placeholder block with placeholder-glow while the real image and text load.

The skeleton reserves the exact space, so the page does not jump when content arrives.

<div class="card" style="max-width:22rem" aria-hidden="true">
  <div class="ratio ratio-16x9 placeholder-glow">
    <span class="placeholder"></span>
  </div>
  <div class="card-body placeholder-glow">
    <span class="placeholder col-7 mb-2"></span><span class="placeholder col-4"></span>
  </div>
</div>
<p class="small text-muted mt-2 mb-0">The skeleton reserves the exact space, so the page does not jump when content arrives.</p>