Font Size Calculator

Generate a typographic scale for consistent font sizes
No font sizes generated yet
Click "Generate Font Sizes" to see the results
Pro tip: Press "/" to focus on base font size input • Use scale factors like 1.25 or 1.618 for harmonious typography

Introduction

Typography is the backbone of design. Whether you’re building a website, designing a mobile app, or preparing print materials, the way your text looks determines readability, hierarchy, and overall user experience. But finding the perfect font size across different screen sizes can be tricky. That’s where the Font Size Calculator comes in.

This tool helps designers, developers, and content creators establish consistent, harmonious typography. From calculating the perfect base font size to scaling heading levels, it makes your text both readable and visually appealing. The calculator also incorporates the Golden Ratio Typography (GRT) method, responsive type scaling, and modular scales to give you professional-grade results.

With the Font Size Calculator, you can:

  • Generate balanced typography using golden ratio principles.

  • Calculate responsive font sizes that adapt across devices.

  • Build a full type scale (H1–H6, body, captions).

  • Ensure readability and accessibility for users.

How to Use Font Size Calculator

Here’s a step-by-step guide to using the tool:

  1. Set Base Font Size
    Choose a starting size (commonly 16px for body text in web design).

  2. Select Scaling Method
    Options include:

    • Golden Ratio (1.618) for visually pleasing proportions.

    • Perfect Fourth, Fifth, or Octave Scales for modular typography.

    • Custom Ratio if you want to fine-tune the scaling.

  3. Generate Typography Scale
    The calculator instantly produces a hierarchy of font sizes for H1, H2, H3, and so on, relative to your chosen base size.

  4. View Responsive Suggestions
    Get recommendations for mobile, tablet, and desktop breakpoints to maintain legibility across devices.

  5. Copy & Apply
    Copy the generated CSS or values into your project.

Why Font Size Matters in Design

Font size isn’t just aesthetics—it directly impacts:

  • Readability: Large enough to read comfortably without straining.

  • Hierarchy: Establishes visual order (headings vs. body text).

  • Accessibility: Ensures inclusivity for users with vision impairments.

  • Responsiveness: Adapts to different screen sizes for consistent UX.

  • Brand Personality: Typography reflects the voice and feel of your brand.

Golden Ratio Typography (GRT)

The Golden Ratio (1.618) is a mathematical principle that creates balance and harmony. Applied to typography, it means scaling your text sizes proportionally for natural readability.

For example:

  • Base font size = 16px

  • H1 = 16px × 1.618 ≈ 26px

  • H2 = 26px ÷ 1.618 ≈ 16px (body)

  • H3 = 16px ÷ 1.618 ≈ 10px (caption/small text)

This ratio produces type that feels visually pleasing, balanced, and natural.

Responsive Font Size Calculator

Today’s users read content on everything from smartphones to ultra-wide monitors. A Responsive Font Size Calculator ensures text looks great everywhere.

Key approaches include:

  • Fluid Typography: Sizes scale automatically between viewport widths.

  • Breakpoint-Based Scaling: Adjust sizes at mobile, tablet, and desktop breakpoints.

  • Relative Units (em/rem): Maintain consistency while allowing flexibility.

Example:

  • Body: 16px (mobile), 18px (tablet), 20px (desktop)

  • H1: 32px (mobile), 40px (tablet), 48px (desktop)

Type Scale Generator

The Type Scale Generator creates a hierarchy of font sizes based on a ratio. This ensures all your text elements look consistent and proportional.

Common modular scale ratios:

  • Minor Second (1.067)

  • Major Second (1.125)

  • Minor Third (1.2)

  • Major Third (1.25)

  • Perfect Fourth (1.333)

  • Perfect Fifth (1.5)

  • Golden Ratio (1.618)

Sample Scale (Base = 16px, Ratio = 1.333):

  • Body: 16px

  • H6: 21px

  • H5: 28px

  • H4: 37px

  • H3: 49px

  • H2: 65px

  • H1: 87px

Conversion Table: px to em/rem

px size em (base 16px) rem (base 16px)
12px 0.75em 0.75rem
14px 0.875em 0.875rem
16px 1em 1rem
18px 1.125em 1.125rem
20px 1.25em 1.25rem
24px 1.5em 1.5rem
32px 2em 2rem
48px 3em 3rem

This table helps web designers shift easily between absolute (px) and relative (em/rem) units for responsive design.

Benefits of Using Font Size Calculator

  • Consistency: Keeps font sizes proportional across design elements.

  • Time-Saving: Automates calculations that would take hours manually.

  • Accessibility: Helps set minimum sizes for readability.

  • Professional Look: Aligns typography with design principles.

  • Scalability: Easy to adapt across different screen sizes.

  • Supports Multiple Methods: Golden ratio, modular scales, and responsive scaling.

Tips & Best Practices

  1. Start with Body Text First
    Establish a base size that’s comfortable for reading.

  2. Use Relative Units
    Stick to rem or em units for scalable, accessible typography.

  3. Check Readability
    Test on actual devices—what looks good on desktop may be too small on mobile.

  4. Maintain Contrast
    Pair font sizes with appropriate line height and color contrast.

  5. Don’t Overuse Ratios
    While mathematical ratios are useful, trust your eye for balance.

  6. Pair with Line Height Calculator
    Good typography needs balanced line spacing, not just font size.

Faqs

It helps designers and developers calculate consistent, proportional font sizes across devices and platforms.

It applies the 1.618 ratio to font sizes to create visually harmonious text scaling.

Use relative units like em/rem, fluid scaling (clamp()), or breakpoints for different devices.

Yes, the calculator generates H1–H6, body text, captions, and more based on modular ratios.

For web design, 16px is the most common and accessible starting point.

No, it’s also useful for print, UI design, and mobile app typography.

It ensures headings and body text are proportional, improving readability and aesthetics.

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