Utilities
76 tools
The general toolbox: the small conversions, checks and lookups that come up all the time. Convert units, colours, time zones and number bases, encode or decode Base64, work out chmod and cron, validate a card or IBAN format, check colour contrast, and more. Everything runs in your browser and keeps working offline once the page has loaded, so there is nothing to install and nothing to sign up for.
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Frequently asked questions
Does the card or IBAN validator confirm the account actually exists?
No. These validators check the format and the check digit — the Luhn algorithm for a card, the mod-97 checksum for an IBAN — which catches typos and impossible numbers. They cannot tell whether the account is real, open or funded; that requires the bank. A number can be perfectly valid in format and belong to no one.
Do the time-zone conversions account for daylight saving time?
Yes. The converter uses your browser's time-zone database, which knows the daylight-saving rules for each region, so a conversion reflects whether either side is currently on summer or winter time. Because those rules change by date, converting a future time uses the offset that will apply on that date, not today's.
Do I need an internet connection for these to work?
Only to load the page the first time. Every tool here computes in your browser, so once it is open it keeps working without a connection — handy for a quick conversion or check on a flaky network. Nothing you enter is sent to a server either way.