The Universal Calculation Engine
The Universal Calculation Engine
Tech Tools

Use these tools for display, color, encoding, and web utilities. Display & Viewport covers screen resolution, browser info, user agent parsing, safe areas, WebP support, PPI, aspect ratio, typography, CSS units, font pairing, file size, and favicon validation. Color Tools helps with color conversion, nearest color names, picker, palettes, gradients, and image-to-palette. Encode & Decode handles Base64, URL, HTML, and Unicode. QR & Barcode generates QR and barcode images. Network includes subnet calculator and bandwidth. Networking / Web Tools offers DNS lookup (A, AAAA, TXT, MX) and CDN checker. AI & LLM offers token counter, AI cost calculator, prompt token simulator, context visualizer, and embedding cost calculator. All tools run in the browser. Search or pick a category below to start.

Tools by category

Screen Resolution Checker
Your current display resolution and pixel density (read-only)
Browser Info
Detected browser, platform, and capabilities
User Agent Parser
Decode a user agent string into browser, OS, engine, and device details
Viewport Size
Current browser window size (updates on resize)
Safe Area Checker
Measure viewport safe-area insets and the usable content zone for notches and rounded corners
WebP Support Checker
Check current browser compatibility for WebP and get fallback / conversion hints
Screen Size / PPI Calculator
Compute PPI from resolution and diagonal, or size from PPI
Aspect Ratio Calculator
Width and height → simplified ratio, decimal, and common name. Or pick a ratio and one dimension to get the other.
From target ratio
File Size Calculator
Estimate uncompressed image or video size from resolution, bit depth, and (for video) FPS and duration.
Favicon Size Checker
Validate favicon and app icon sizes against common browser, Apple touch, and PWA recommendations
Responsive Viewport Tester
Test a URL at preset or custom viewport widths in an iframe
Many sites block being embedded (CSP / X-Frame-Options). Use your own site, localhost, or a URL that allows framing (e.g. example.com).
Favicon Generator
Create favicons from an image (resized) or from text; download common sizes
Pixel Ruler
On-screen ruler to measure pixels. Toggle horizontal/vertical and drag to position.
Click "Show ruler" to display a draggable ruler overlay. Use it to measure elements on the page.
Grid Overlay Generator
Generate a column grid (CSS or visual overlay) with configurable columns, gutter, and margin
Typography Converter
Convert between px, pt, and em (16px base)
Result
—
CSS Unit Converter
Convert between px, rem, em, vw, and vh using custom base font size and viewport dimensions
Font Pairing Suggestions
Suggest popular heading + body font combinations for product, editorial, elegant, or technical layouts

Get fonts: Google Fonts. Search by name to add to your project.

IP Subnet Calculator
IPv4 & IPv6 subnet analysis: network, broadcast, host range, and binary breakdown
Color Code Converter
Paste any color format to get HEX, RGB, HSL, HSV, CMYK with copy and live preview
Recent colors
Palette
Contrast (WCAG)
Color Namer
Convert a HEX or CSS color to the nearest named color match
Contrast Checker
Check WCAG contrast ratio between foreground and background colors
Accessible Color Palette
Generate WCAG-compliant color palettes from a base color
Color Temperature
Convert between Kelvin and RGB (black-body style approximation)
Color Blindness Simulator
Preview how a color appears under common color-vision deficiencies
Color Picker (Eyedropper)
Pick a color from your screen using the browser eyedropper
Color Palette Generator
Generate full palettes from a base color or random: complementary, triadic, analogous, or monochromatic
Base Color
#3B82F6
Gradient Generator
Build linear or radial CSS gradients with color stops, then copy CSS
Gradient to CSS / Tailwind / SVG
Export a gradient as CSS, Tailwind arbitrary value, or SVG linearGradient

Use the SVG block inside <defs> and reference with url(#id).

Image → Color Palette
Upload an image to extract dominant colors (palette). Max 5 MB.
Encoders & Decoders
Encode and decode text instantly. All processing happens locally.
QR Code Generator
Enter text or URL to generate a QR code image
Barcode Generator
Generate Code 128 barcode from text or numbers
Bandwidth Calculator
Data size and speed → time to download; or size and time → required speed
DNS Lookup
View DNS records (A, AAAA, TXT, MX) via DNS over HTTPS
CDN Checker
Check which CDN a site uses (from response headers)
Token Counter (OpenAI, Claude)
Estimate token counts for OpenAI and Claude from text (character/word-based approximation)
AI Cost Calculator
Estimate API cost from input/output token counts for OpenAI and Anthropic models
Prompt Token Simulator
Simulate prompt + completion token cost for a single request
LLM Context Visualizer
Show token distribution and counts for prompt text
Embedding Cost Calculator
Estimate cost for text embedding API by token count

Hundreds of fast, free calculators, converters, and practical tools for work and everyday life

A universe of useful calculators and tools

Explore hundreds of free calculators, converters, and practical utilities for finance, real estate, business, math, engineering, text, and development — all in one clean experience.

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Free to use

No paywall to access core tools

Clean by design

Fast, focused, distraction-light interface

Broad coverage

Math, money, property, text, code, and more

Always growing

New tools are added regularly

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