Aspect Ratio Calculator — Change Image & Video Aspect Ratio Online

Instagram Aspect Ratio — Posts, Reels & Stories

The Instagram aspect ratio varies by format. The key insight: Instagram crops any image or video that doesn't match the expected ratio — so getting it right before upload avoids unintentional cropping of your subject. Use the calculator above with Instagram presets to verify dimensions instantly.

What aspect ratio is Instagram? The Instagram post aspect ratio for the feed ranges from 1.91:1 (landscape) to 4:5 (portrait). Instagram Stories and Reels both use 9:16 vertical. The 4:5 portrait ratio (1080×1350) is the best choice for feed posts — it occupies more vertical space, reducing scroll speed and increasing engagement. The Instagram Reels aspect ratio is 9:16 at 1080×1920px; always keep important UI elements within the central safe zone to avoid overlap with buttons.

YouTube Aspect Ratio — Videos, Shorts & Banners

The YouTube aspect ratio for standard videos is 16:9, which matches all modern widescreen monitors and TVs. YouTube will add black "pillarboxes" to any video that doesn't match 16:9, so always export at the correct ratio.

What is the aspect ratio of YouTube Shorts? YouTube Shorts uses 9:16 vertical format at 1080×1920 pixels. Shorts filmed in 16:9 (horizontal) will appear with black bars on mobile. The YouTube banner is 2560×1440 — a 16:9 ratio — with a "safe area" of 1546×423px in the center that displays across all devices.

TikTok Aspect Ratio — Videos & Ads

The TikTok aspect ratio is 9:16 vertical (1080×1920px) for standard videos. TikTok is designed for full-screen vertical viewing on mobile, so 9:16 is the only format that fills the entire screen without cropping or black bars.

• TikTok Feed Video: 9:16 at 1080×1920px (recommended); can also upload 1:1 and 16:9
• TikTok TopView / Brand Takeover Ads: 9:16 at 1080×1920px, max 60 seconds
• TikTok In-Feed Ads: 9:16, 1:1, or 16:9; 9:16 performs best
• Safe Zone: Keep text and branding between y=268px and y=1794px to avoid overlap with like/comment buttons and bottom username area

What aspect ratio is TikTok? TikTok's native ratio is 9:16. Unlike YouTube which pads any ratio to 16:9, TikTok will pan-and-scan horizontal 16:9 videos on the "For You" page — this crops out much of the original frame. Always film or export in 9:16 for TikTok.

16:9 vs 4:3 Aspect Ratio — Which to Use?

The 16:9 aspect ratio and the 4:3 aspect ratio are the two most historically important display standards. Today, 16:9 dominates digital media, but 4:3 remains relevant for certain presentations, legacy displays, and video on classic TV.

In practice: use 16:9 for any modern video destined for YouTube, Vimeo, or TV. Use 4:3 only if your content archivally matches that era (old footage, presentation slides) or if the platform specifically recommends it. PowerPoint and Google Slides default to either 16:9 or 4:3 — verify your export format before creating 50 slides.

Tire Aspect Ratio — What It Means on Your Car

The tire aspect ratio is the numeric component of a tire's size code that indicates the cross-section profile of the tire. This is a completely different definition from image or video aspect ratio — in automotive engineering, it means the height-to-width percentage of the tire sidewall.

How to read a tire code: 205/55 R16

• 205 — tread width in millimetres (how wide the tire is)
• 55 — aspect ratio (sidewall height = 55% of 205mm = 112.75mm)
• R16 — rim diameter in inches

What is aspect ratio on a tire? A lower tire aspect ratio (e.g., 35 or 40) means a shorter, stiffer sidewall — this improves handling responsiveness and cornering precision at the cost of a harsher ride. A higher aspect ratio (e.g., 65 or 70) gives a taller sidewall that absorbs more road shock, improving ride comfort but reducing cornering sharpness. Most performance cars use 35–50 series tires; family sedans typically use 55–65 series.

How to Change Aspect Ratio in Premiere Pro

Changing the aspect ratio in Premiere Pro affects the entire sequence — all clips will be re-framed. There are two methods:

1. Sequence Settings method (recommended): Go to Sequence → Sequence Settings → change Frame Size width and height to your target dimensions (e.g., 1080×1920 for 9:16 vertical). Premiere will auto-crop or letterbox clips that don't match.
2. New Sequence method: Create a new sequence with your target settings, then copy-paste your clips into it. This preserves the original sequence untouched.
3. Export-only method: Keep your timeline dimensions, but in File → Export → Media, set a custom output resolution under Video → Width/Height. This crops the output without modifying the timeline — useful for repurposing one 16:9 edit as a 9:16 short.

How to change aspect ratio in Premiere Pro for social media: The fastest workflow for repurposing is the Premiere Pro "Reframe" auto-reframe feature (under Sequence → Auto Reframe Sequence). For 9:16 TikTok/Reels export, choose the 9:16 preset and set motion tracking to "Slower" for talking-head videos. Always preview the auto-reframe before exporting.

What is Aspect Ratio? — Complete Guide

Aspect ratio is the proportional relationship between the width and height of a two-dimensional shape — most commonly an image, screen, or video frame. It is always expressed as two numbers separated by a colon: width:height.

The simplified ratio for any set of pixel dimensions is found by dividing both values by their Greatest Common Divisor (GCD). For example: 1920×1080 → GCD(1920, 1080) = 120 → 1920/120 : 1080/120 = 16:9.

Aspect ratio in computer graphics: In digital design, aspect ratio determines how an image scales and displays across different screen sizes. A fixed aspect ratio ensures that an image appears correctly proportioned on any device — from a 375px phone to a 4K monitor. CSS developers use the aspect-ratio property (e.g., aspect-ratio: 16 / 9) to enforce consistent proportions in responsive layouts.

Why aspect ratio matters more than resolution: Two images can have different resolutions but the same aspect ratio — 1280×720 and 1920×1080 are both 16:9. The ratio defines the shape; the resolution defines the quality. Always define both when specifying media formats.

Aspect Ratio of Standard ISO Paper Sizes

The aspect ratio of standard ISO paper sizes (A0, A1, A2, A3, A4, A5) is always 1:√2 ≈ 1:1.4142. This elegant design means that when you fold any A-size sheet in half along its longer edge, you get the next smaller A-size — and the aspect ratio stays identical.

The US Letter format (8.5×11 in / 216×279mm) has an aspect ratio of approximately 1:1.294, which does not share the √2 property — meaning US Letter cannot be halved to produce a proportionally identical smaller sheet. This is why PDFs formatted for A4 often have white bars when printed on US Letter.

Common Aspect Ratios — Reference Guide