Free Online Tools

Calculate air density from temperature, pressure, and humidity, or from altitude. Shows kg/m³, virtual temperature, speed of sound, and comparison to sea-level standard. Free, browser-based.

Calculate bolt tightening torque, clamp preload, and nut factor K. Modes: torque from preload (T = KDF), preload from torque, recommended torque from proof load and bolt grade, and nut-factor solver. Metric (mm, kN, N·m) and imperial (in, lbf, lbf·ft) with M6–M24 and Grade 5/8 presets. Free, browser-based.

Graph mathematical functions y = f(x) instantly. Enter expressions like sin(x), x^2, exp(x), or multiple functions — get an SVG plot with axes, grid, and auto-scaling. Free, browser-based.

Convert PDF pages to JPG images in your browser with adjustable quality and resolution.

Combine multiple PDF files into one document in your browser, with drag-free reordering and instant download.

Add password protection and permission restrictions to PDF files entirely in your browser.

Upload a PDF and generate an AI summary using your own OpenAI, Anthropic, Google, or Groq API key.

Draft professional emails with AI using your own OpenAI, Anthropic, Google, or Groq API key.

Generate SEO-friendly blog posts with title, meta description, and markdown content using your own AI API key.

Resize images in your browser with custom dimensions, aspect-ratio lock, and format export.

Convert images between PNG, JPG, WebP, AVIF, and BMP right in your browser, with quality control and transparency handling.

Compress images in your browser by adjusting quality, output format, and max dimensions to reduce file size.