Free tools that run in your browser

Nothing you type is uploaded, logged or stored. No account, no upload, no server doing the work.

Converters

QR code generator
Links, WiFi details or contact cards, with colors, shaped modules and a center logo.
Hash generator
MD5, SHA-1, SHA-256, SHA-384 and SHA-512, in hex or base64.
Cover image generator
The dark technical-schematic cover this site draws for its own posts -- eyebrow, title, subtitle and a small box-and-arrow diagram.
Barcode label maker
Code 128, EAN-13, UPC-A, ITF-14 and Data Matrix labels as a PDF for Avery sheets, from a pasted list or CSV.
Barcode scanner
Read linear and 2D codes from the camera or a photo, then copy them or save them as CSV.

Unix timestamp converter
Epoch to date and back, in seconds, milliseconds or microseconds.
Broken image checker
Paste a page's HTML or a list of image URLs and every one is loaded to see whether it still resolves - srcset candidates, lazy-loading attributes and CSS backgrounds included.
Symfony and PHP version checker
The minimum PHP for every Symfony version, which are long-term support, and when their fixes end - from symfony.com's own data.
Redirect code generator
One redirect as copyable code for .htaccess, nginx, PHP and Symfony, with 301, 302, 307 or 308.
Image converter
PNG and JPEG to WebP, in batches, without uploading anything.

$The percentage calculator in use$
Percentage calculator
Percentage of, percentage change, and adding or removing a percentage.
Geometry calculator
Area, perimeter, volume and surface area for common shapes.

Serialized PHP repair
Fix plugin and theme settings that vanished after a domain change.
Salt and key generator
The eight wp-config.php security keys, generated in your browser.
.htaccess redirect generator
Escaped, anchored 301 rules from a list of old and new URLs.

Hyperbolic Time Chamber converter
One day outside is one year inside. Work it out in either direction.
BP to BC converter
Radiocarbon and archaeological dates, handling the missing year zero that most converters get wrong.

Every tool here was rebuilt rather than ported. The originals dated from 2015, and each one keeps its original address so an old link still works.