Free & private, in your browser
Kelvido
Free tools that never leave your browser.
No sign-up. Nothing to install. Nothing ever leaves your device.
Most popular
YouTube Thumbnail Checker
Upload a thumbnail and check its format, size, and 16:9 aspect ratio against YouTube's official requirements before you upload it.
Word Counter & Character Counter
Instant word, character, sentence and paragraph counts, reading time, text insights, and length references for X/Twitter, SMS, and more.
Markdown → HTML
Paste Markdown to see it rendered live and get the HTML source to copy — CommonMark + GFM tables/strikethrough, raw HTML always shown as text, never executed.
Browse by category
8 categories today — more are added as the collection grows.
YouTube Creator Tools
Free tools to help you publish faster and avoid silent mistakes.
3 tools →
Text Tools
Fast, general-purpose text analysis — no platform required.
6 tools →
Web & Developer Tools
Small utilities for building and securing things online.
19 tools →
Converters
Convert between formats — Markdown, HTML, JSON, YAML.
12 tools →
Image Tools
Resize, compress, and convert images — processed locally.
5 tools →
Calculators
Loans, mortgages, health, dates — calculated locally.
12 tools →
Color Tools
Convert, check, and generate colors and palettes.
3 tools →
PDF Tools
Merge, split, rotate, and build PDFs — processed locally.
5 tools →
Why Kelvido?
Privacy first
Everything runs in your browser. Nothing is ever uploaded or stored.
Instant results
No loading spinners, no server round-trips. Results update as you type.
Works everywhere
No install, no account. Works in any modern browser, on any device.
More tools are added regularly.