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Unreasonably Useful
Sites that quietly do a job you would otherwise pay for or install software for. Included because being this good for free is genuinely strange.
15 sites
Type the name of any app and get a crowd-ranked list of alternatives, filtered by platform, price and whether the project is open source.
Type any web feature and see which browsers support it, version by version, alongside how many people actually use each one.
- <1 min
- Desktop
Translates a cron expression into plain English as you type it, then tells you when it will next fire. Ends a very specific argument.
- <1 min
- Desktop
Paste two blocks of text and get a colour-coded diff back immediately. Also handles PDFs, images and spreadsheets.
- <1 min
- Desktop
Paste a website address and learn whether it is down for the whole world or only for you. Settles the argument with your router in seconds.
- <1 min
Full flowchart, floorplan and network-diagram editor that saves to your own drive and has never once asked anyone for money.
- 10 min
- Desktop
Slide across a stack of time zones and see the hour for everyone at once. The quickest way to find a meeting slot that spans continents.
- <1 min
Hand-drawn-looking diagrams that somehow stay legible, with live collaboration and no account. The whiteboard for people who hate whiteboards.
- 10 min
- Desktop
Paste a terrifying shell command and it pulls the whole thing apart, annotating every flag from the relevant man page.
- <1 min
- Desktop
An internet speed test that starts the moment the page opens and shows one big number. Tap for upload speed and latency if you want more.
- <1 min
Merge, split, compress, rotate, sign and convert PDFs from a single page. Covers nearly everything Acrobat charges a subscription for.
A big set of free PDF tools in the browser: merge, split, compress, convert and sign documents without creating an account first.
Builds a regular expression while explaining every token in a side panel and highlighting matches as you type. Ends a lot of guessing.
- 10 min
- Desktop
World clocks, time-zone converters, sunrise and moon times, calendars and countdowns, all on one long-running and reliably accurate site.
Answers computed rather than retrieved: integrals, unit conversions, orbital mechanics and the nutritional content of a Mars bar.
How we picked these
Every entry in Detour is hand-sorted rather than scraped: filed under one category, given one to three moods, and placed in a time band for how quickly it pays off. The practical facts — cost, sign-up, sound, device and whether it is safe at a desk — are recorded per site and shown on every card, so you can rule things out before you click.
Unreasonably Useful: questions
How many sites are in Unreasonably Useful?
15 sites, each hand-sorted by category, mood and how long it takes to pay off.
Which of these sites are free with no sign-up?
15 of the 15 are free and need no account. None of them are paid.
Do these sites work on a phone, and are they safe for work?
8 of 15 work on a phone; the rest are desktop only. 15 are safe for work and 15 work with the sound off.