The 7 Best Aspect Ratio Calculator Tools Compared

The "best" aspect ratio calculator depends on what you are doing: quick lookups, social media production, design-tool integration, video editing, or batch operations. This guide ranks seven of the most useful aspect ratio calculator tools — browser-based, designer-friendly, and built into other apps — and identifies which is best for which use case, with explicit strengths, weaknesses, and pricing.

Quick rankings

1. Screen Ruler aspect ratio calculator — best default for any quick aspect ratio question.
2. Figma's Frame Resizer — best when you are already in Figma.
3. Calculator.net Aspect Ratio Calculator — solid alternative with a clean form interface.
4. Andrew Hedges Aspect Ratio Calculator — long-running, minimal, popular among developers.
5. Adobe Premiere Pro / Final Cut presets — best for video projects you are already editing.
6. Custom JavaScript snippets — best when integrating into your own tool or website.
7. Generic proportion calculator — backup option when dedicated tools are unavailable.

1. Screen Ruler aspect ratio calculator

The Screen Ruler ARC is part of the broader Screen Ruler toolkit (which also includes a calibrated screen ruler, a protractor, a dead pixel test, and a device specs database). It supports width-and-height → ratio, ratio-and-dimension → missing dimension, and common preset shortcuts.

Strengths:

• Free, no install, no account.
• Common presets: 16:9, 9:16, 4:5, 1:1, 21:9, 4:3, 2.39:1.
• Bidirectional: pixels ↔ ratio.
• Auto-simplification: 1920 × 1080 → 16:9.
• 20-language interface.
• Mobile-optimized.
• Cross-tool integration with Screen Ruler's other utilities.

Weaknesses:

• Does not export images. It computes; you apply elsewhere.
• No batch processing. One ratio at a time.

Best for: any quick aspect ratio question. The default tool.

Cost: free.

2. Figma's Frame Resizer

Figma has built-in aspect ratio handling: shift-drag a frame's corner to maintain proportions, or set explicit dimensions in the right-side properties panel. Figma also has community plugins (e.g. "Aspect Ratio Lock") that add explicit ratio-locking with degree-by-degree control.

Strengths:

• Already inside the design tool. No app switching.
• Visual feedback: see how the resize affects layout in real time.
• Plugins extend the basic functionality.

Weaknesses:

• Does not display the ratio explicitly. A 1920 × 1200 frame stays 1920 × 1200; the tool does not say "this is 16:10."
• Requires a Figma account.
• Limited to design contexts.

Best for: designers who are already in Figma and want to maintain frame proportions during editing.

Cost: Figma is free for individuals; team plans $12/editor/month.

3. Calculator.net Aspect Ratio Calculator

Calculator.net's aspect ratio calculator is a long-standing form-based tool. Enter width and height, get the simplified ratio.

Strengths:

• Free, no install, no account.
• Established and widely cited.
• Form-based interface that is friendly to non-technical users.

Weaknesses:

• Heavier ad load than minimal alternatives.
• Limited preset support.
• English-only.
• Older UI. Functional but not as polished as modern tools.

Best for: a backup if your default ARC is unavailable.

Cost: free (ad-supported).

4. Andrew Hedges Aspect Ratio Calculator

Andrew Hedges' aspect ratio calculator is a developer-leaning minimalist tool, popular in graphics and video communities since the 2000s.

Strengths:

• Minimal interface. Nothing but the inputs and the result.
• Loads instantly. Very small page.
• Free.
• No tracking or ads.

Weaknesses:

• Only does pixel-to-pixel calculation (e.g. "I have 1920 × 1080, what is W if H is 720?").
• No simplification or preset menu.
• No mobile-specific UI.

Best for: developers and video professionals who know exactly what calculation they need and want a clean, minimal tool.

Cost: free.

5. Adobe Premiere Pro / Final Cut Pro / DaVinci Resolve presets

Video editors all have aspect ratio presets in their project settings. Premiere Pro: File → Project Settings → General → Display Format. Final Cut Pro: File → Project Properties → Format. DaVinci Resolve: Project Settings → Master Settings.

Strengths:

• Already inside the editor.
• Sets the project's frame size to match.
• Common ratios are one click.

Weaknesses:

• Limited to the preset list. Custom ratios require manual frame size entry.
• Editor required. Premiere $20.99/month; FCP $300 one-time; DaVinci Resolve free with paid Studio version.
• Only useful inside that editor.

Best for: video editors setting up a project with a standard ratio.

Cost: Premiere $20.99/month, FCP $300 one-time, DaVinci Resolve free.

6. Custom JavaScript snippets

For developers integrating aspect ratio calculation into a custom tool or website:

function gcd(a, b) {
  return b === 0 ? a : gcd(b, a % b);
}

function aspectRatio(width, height) {
  const divisor = gcd(width, height);
  return `${width / divisor}:${height / divisor}`;
}

aspectRatio(1920, 1080); // "16:9"

This 5-line function does what every ARC does internally.

Strengths:

• Full control. Embed in your own UI.
• No external dependencies.
• Free.
• Customizable. Add weighted ratios, special handling, presets specific to your domain.

Weaknesses:

• Requires coding knowledge. Not a casual-user solution.
• No visual UI without additional work.
• Maintenance burden.

Best for: developers building branded calculator tools or in-app aspect ratio handling.

Cost: free (your own dev time).

7. Generic proportion calculator

Generic proportion calculators ("a/b = c/?") work for aspect ratios when treating them as a ratio. Many free ones exist online.

Strengths:

• Free, no install.
• Works for any proportion question, not just aspect ratios.

Weaknesses:

• Does not simplify ratios.
• No preset menu.
• Less aspect-ratio-specific functionality.

Best for: a backup when dedicated ARC tools are unavailable.

Cost: free.

Comparison table

Tool	Presets	Auto-simplify	Mobile UI	Design integration	Cost
Screen Ruler ARC	Yes	Yes	Yes	No	Free
Figma Frame Resizer	Implicit	No	OK	Yes	Free / paid
Calculator.net	Limited	Yes	OK	No	Free
Andrew Hedges	No	No	OK	No	Free
Premiere/FCP/Resolve	Yes	No	No	Yes (video)	Editor cost
Custom JS	Customizable	Customizable	Custom	Custom	Free (dev time)
Generic proportion calc	No	No	OK	No	Free

Choosing by scenario

Situation	Best tool
Quick aspect ratio question	Screen Ruler ARC
Resizing in Figma	Figma's frame resizer
Setting up a Premiere project	Premiere preset
Building a calculator into your own site	Custom JS
Need a backup tool	Calculator.net or Andrew Hedges

For most users, the Screen Ruler ARC handles 90% of cases. The other rows are specialists.

How to combine tools

• ARC for the math, editor for the application. Compute the ratio in the calculator, set up the project in Premiere/FCP using the calculated frame size.
• ARC for the math, Figma for the design. Compute the dimensions, create a frame at that size in Figma, design within.
• Custom JS for repeated calculations. If you do dozens of aspect ratio calculations daily for your work, a custom snippet saves clicks.

Common mistakes when choosing

• Picking the most full-featured tool by default. Custom JS is powerful but slower than a click-to-use calculator for casual users.
• Trusting an editor preset for non-standard ratios. If you need 22:9 (uncommon ultrawide), the preset menu may not have it.
• Overlooking mobile compatibility. If you do production work on a phone or tablet, mobile-optimized tools matter.
• Not bookmarking the tool. A bookmarked ARC is one click away; an unsavored one means you re-google "aspect ratio calculator" every time.

What about app-store ARC apps?

Both iOS and Android have aspect ratio calculator apps. Most replicate the same web functionality without adding much. The exceptions are AR-camera-overlay apps that show frame guides over a live camera feed (useful for filming with specific aspect ratios in mind).

For everyday use, browser-based ARC has the same functionality without install overhead.

Summary

Seven aspect ratio calculator tools, each with a specific best-fit niche. The Screen Ruler ARC is the recommended default — free, mobile-optimized, with presets and auto-simplification. Figma is best when you are already in Figma. Premiere/FCP presets when in those editors. Custom JS for developers building integrations. The others are specialists or backups.

For background, see the aspect ratio pillar guide. For the calculation procedure in detail, see how to calculate aspect ratio from pixels.

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This article supports the Screen Ruler aspect ratio calculator tool.