Công cụ trực tuyến miễn phí
405+ free online tools for PDF, images, SEO, developers, color, and productivity. Fast, browser-based, and private — no signup, no installs, no limits. Search above or browse by category below.
Total tools405Available free tools
Categories15Active categories
Most usedCSV to ExcelPopular right now
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SQL Formatter
Format and beautify SQL queries with indentation, keyword casing, and readable clause breaks.
Border Radius Generator
Design CSS border-radius values per corner with live preview and copy-ready CSS, inline styles, and Tailwind classes.
Ping Test
Ping a hostname or IP from the server. Check reachability, packet loss, and round-trip latency.
Times Tables Trainer
Free times tables trainer — pick a multiplication table from 2 to 12, practice random prompts, and track your mastery percentage.
Instagram Reels Downloader
Download public Instagram Reels as MP4 — paste a Reel link, preview, and save. Public content only.
CSS Loader Generator
Create animated CSS loading spinners with live preview. Copy HTML, keyframes, and full CSS snippets.
Subnet Calculator
Calculate IPv4 subnet details from CIDR notation or a subnet mask. Get network, broadcast, and host ranges instantly.
React Icon to SVG Converter
Free React icon to SVG converter — paste JSX or pick a Lucide icon, live preview, download SVG or multi-size ICO favicons.
Gamertag Unicode Stylizer
Free gamertag Unicode stylizer — turn your name into bold, italic, bubbled, and other fancy Unicode styles. Copy any variant instantly.
QR Code Generator
Free QR code generator — create custom QR codes for URLs, Wi‑Fi, vCard, and more. Add colors and logo, then download PNG or SVG. No signup.
Molarity Calculator
Molarity calculator free — find M, moles, or volume with M=n/V. Convert mass to molarity using formula lookup. Instant chemistry in your browser.
River Discharge Calculator
Calculate river discharge Q from channel width, depth, and mean velocity (velocity–area method), trapezoidal cross-sections with bank slope, or Manning's equation. Results in m³/s, L/s, and CFS with river size classification. Free, browser-based.