Design & Multimedia
Font Size Calculator
Calculate responsive font sizes
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Frequently asked questions
What does the Font Size Calculator do?
It helps you calculate responsive font sizes.
What inputs do I need?
Enter Minimum font size, Maximum font size, Minimum viewport, and Maximum viewport.
Are decimals supported?
Yes, you can use decimal values where appropriate.
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About this tool
Inputs
- Minimum font size
- Maximum font size
- Minimum viewport
- Maximum viewport
Results
- Slope
- Intercept
Numbers tell a story, and the Font Size Calculator helps you read it. Plug in your data to see what the math reveals. The required inputs are minimum font size, maximum font size, minimum viewport and maximum viewport. Once provided, the result — slope and intercept — appears instantly. Responsive design requires translating between physical units (inches, pt) and digital units (px, em, rem).
Font size in pixels = font size in pt × DPI / 72. People frequently need to calculate responsive font sizes but lack a quick way to do it — this tool fills that gap. WCAG AA requires a contrast ratio of at least 4.5:1 for normal text and 3:1 for large text. Accessibility standards (WCAG) set minimum contrast ratios to ensure text is readable for people with visual impairments. Run the calculation with your best-case and worst-case assumptions to bracket the likely outcome.