Free online tech tools calculators and tools. Browse and use all Tech Tools tools on Calciverse.
Generate WCAG-compliant color palettes from a base color
Estimate API cost from input/output token counts for OpenAI and Anthropic models
Width and height → simplified ratio, decimal, and common name. Or pick a ratio and one dimension to get the other.
Data size and speed → time to download; or size and time → required speed
Generate Code 128 barcode from text or numbers
Detected browser, platform, and capabilities
Check which CDN a site uses (from response headers)
Preview how a color appears under common color-vision deficiencies
Paste any color format — get HEX, RGB, HSL, HSV, CMYK with copy and live preview
Convert a HEX or CSS color to the nearest named color match
Generate full palettes from a base color or random: complementary, triadic, analogous, or monochromatic
Pick a color from your screen using the browser eyedropper
Convert between Kelvin and RGB (black-body style approximation)
Check WCAG contrast ratio between foreground and background colors
Convert between px, rem, em, vw, and vh using custom base font size and viewport dimensions
View DNS records (A, AAAA, TXT, MX) via DNS over HTTPS
Estimate cost for text embedding API by token count
Encode and decode text instantly. All processing happens locally.
Validate favicon and app icon sizes against common browser, Apple touch, and PWA recommendations
Create favicons from an image (resized) or from text; download common sizes
Estimate uncompressed image or video size from resolution, bit depth, and (for video) FPS and duration.
Suggest popular heading + body font combinations for product, editorial, elegant, or technical layouts
Export a gradient as CSS, Tailwind arbitrary value, or SVG linearGradient
Build linear or radial CSS gradients with color stops — copy CSS
Generate a column grid (CSS or visual overlay) with configurable columns, gutter, and margin
Upload an image to extract dominant colors (palette). Max 5 MB.
Show token distribution and counts for prompt text
On-screen ruler to measure pixels. Toggle horizontal/vertical and drag to position.
Compute PPI from resolution and diagonal, or size from PPI
Simulate prompt + completion token cost for a single request
Enter text or URL to generate a QR code image
Your current display resolution and pixel density (read-only)
Measure viewport safe-area insets and the usable content zone for notches and rounded corners
IPv4 & IPv6 subnet analysis — network, broadcast, host range, and binary breakdown
Estimate token counts for OpenAI and Claude from text (character/word-based approximation)
Convert between px, pt, and em (16px base)
Decode a user agent string into browser, OS, engine, and device details
Current browser window size (updates on resize)
Test a URL at preset or custom viewport widths in an iframe
Check current browser compatibility for WebP and get fallback / conversion hints