Hash generator

Common questions

• What is a hash used for?

  It reduces any input to a fixed-length fingerprint. The same text always gives the same digest, and changing one character changes all of it, which is what makes a hash the standard way to check a download arrived intact, spot a duplicate file, or index content without storing it.

• Can I get the original text back from a hash?

  No. Hashing is one-way and throws information away — SHA-256 maps an input of any length onto 32 bytes. What is sold as a hash decrypter is a lookup table of digests somebody computed earlier, which is exactly why a short or common input gains nothing from being hashed.

• Why is there no MD5?

  Because browsers do not offer one. WebCrypto implements SHA-1 and the SHA-2 family and deliberately omits MD5, for which collisions have been trivial since 2004. Putting it back would mean shipping a hand-written implementation of a digest nobody should be choosing today.

• Is SHA-1 still safe to use?

  Not for anything an attacker can influence. A chosen-prefix collision was demonstrated in 2017 and is affordable now, so SHA-1 must not be used for signatures or certificates. It remains fine as a plain integrity check, and it is what Git object ids and many older systems use — which is why it is here.

• Can I use this to hash a password?

  You can, but do not store the result. A plain SHA digest is far too fast: a single GPU works through billions of guesses a second, so a stolen table of them falls quickly. Password storage needs a deliberately slow algorithm with a per-user salt — bcrypt, scrypt or Argon2 — not a general-purpose hash.

Other tools

• Weight Converter →kg, lb, oz, g, stone and tonnes
• Height Converter →cm, m, feet and inches
• Temperature Converter →Celsius, Fahrenheit and kelvin
• Speed Converter →km/h, mph, m/s, ft/s and knots
• Volume Converter →Litres, millilitres, gallons, pints and cups
• Area Converter →m², sq ft, acres, hectares and sq miles
• Time Converter →Milliseconds, seconds, minutes, hours and days
• Data Storage Converter →Bytes, KB, MB, GB, TB and KiB, MiB, GiB, TiB
• Percentage Calculator →Percent of, percent change, increase and decrease
• Age Calculator →Years, months, days and your next birthday
• Word Counter →Words, characters, sentences and reading time
• Case Converter →UPPER, lower, Title, camelCase and snake_case
• Base64 Encoder →Encode and decode base64, Unicode included
• URL Encoder →Percent-encode and decode, safely either way
• Typing Speed Test →Words per minute, accuracy and your best
• BMI Calculator →Body mass index, body fat and daily energy
• Lorem Ipsum Generator →Placeholder text by paragraph, sentence, word or character
• UUID Generator →Random version 4 UUIDs, up to 100 at once
• Password Generator →Strong random passwords, generated locally
• Decibel Meter →Live sound level from your microphone, in dB

See all 3 generators →