COSTUI
Design better interfaces — UI/UX guides, design-system references, and the free calculators every front-end builder needs.
From checking color contrast and converting px to rem to building type and spacing scales, generating color ramps, and working out aspect ratios, CostUI pairs free hands-on design calculators with practical guides and a browsable museum. Design clearer, build faster.
UI/UX Design Tools & Calculators
Free tools for interface work — color contrast checker, px to rem converter, type scale generator, color shades generator, spacing scale generator, and aspect ratio calculator.
Color Contrast Checker
Check the WCAG 2.1 contrast ratio between a text and background color, with pass/fail for AA and AAA at normal and large text sizes.
PX to REM Converter
Convert pixels to rem or rem to pixels for any root font size, with a reference table of the sizes you reach for most.
Type Scale Generator
Build a modular type scale from a base size and a ratio — minor third, major third, perfect fourth, golden — in px and rem.
Color Shades Generator
Turn one base hex into a full ramp of tints and shades from 10% to 90%, ready to paste into your palette or design tokens.
Spacing Scale Generator
Generate a consistent spacing scale from a base unit — linear or geometric — with every step in px and rem.
Aspect Ratio Calculator
Solve a missing width or height for any ratio, or reduce a pixel size to its simplest ratio.
The Museum
A browsable museum sits alongside the calculators and guides — a set of illustrated collections you can explore when you want a break from the numbers, with every entry drawn from Wikipedia and Wikimedia Commons.
Tour the museum →From the Journal
Guides on color and accessibility, typography and type scales, spacing and layout, design systems, and front-end CSS — practical reading to pair with the calculators above.
Why Budget-Friendly Graphic Templates Are Revolutionizing Visual Content Creation
The Ultimate Resource for Affordable Graphic Design Templates That Deliver Professional Results Without Breaking the Bank In today’s visually driven digital landscape, high-quality graphics are essential across industries—from marketing campaigns and website design to social media branding and print materials. Yet many small businesses, freelancers, and creative professionals face a common challenge: creating professional-grade visuals […]
The Affordable Artistry of Web Design: Mastering Low-Cost Website Themes Without Compromise
The Affordable Artistry of Web Design: Mastering Low-Cost Website Themes Without Compromise In today’s digital marketplace, establishing an online presence is not merely optional—it’s essential. Yet many entrepreneurs, small business owners, and creative professionals find themselves at a crossroads when choosing between premium design solutions and budget-friendly alternatives. This guide explores how low-cost website themes […]
The Power of UX Design Templates: Streamlining Creativity and Consistency in Digital Experiences
The Power of UX Design Templates: Streamlining Creativity and Consistency in Digital Experiences In today’s fast-paced digital landscape, creating user-friendly interfaces demands both speed and precision. UX design templates offer an efficient solution by providing pre-built frameworks that help designers maintain consistency while accelerating project timelines. These templates are invaluable tools for professionals ranging from […]
The Art of Seamless Interaction: Mastering Modern App Interface Design Principles
The Art of Seamless Interaction: Mastering Modern App Interface Design Principles In today’s hyper-connected digital landscape, app interface design has evolved from mere aesthetics to a critical component that defines user satisfaction and business success. As mobile technology continues its relentless march forward, developers and designers must navigate an ever-changing ecosystem where usability, accessibility, and […]
Decoding UI/UX Consulting: What It Truly Means for Modern Enterprises
The Strategic Edge of UI/UX Consulting: Transforming Digital Experiences Through Expert Design Thinking In an era where digital experiences dictate brand loyalty and customer retention, businesses are increasingly turning to specialized expertise to ensure their products stand out in crowded markets. This is where UI/UX consulting emerges as a critical lifeline, offering strategic guidance that […]
The Art of Seamless Interaction: Mastering User Experience Design Principles
The Art of Seamless Interaction: Mastering User Experience Design Principles User experience design is an intricate blend of psychology, aesthetics, and technology that shapes how users interact with digital products. At its core, UX design focuses on creating intuitive interfaces that simplify complex tasks while delighting users through thoughtful interactions. In today’s competitive landscape, exceptional […]
Keep Learning
Plain-language explainers on how contrast ratios, rem units, modular type scales, spacing systems, and aspect ratios actually work — everything you need to design and build interfaces with more confidence.
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