Java String HashCode Calculator

Match Java signed 32-bit string hashing

Java String hashCode starts at zero and updates with previous hash times 31 plus the next UTF-16 code unit, wrapping as a signed 32-bit integer. This calculator follows that contract directly, reporting signed decimal and the same bit pattern as eight unsigned hexadecimal digits. It helps debug map keys, serialized fixtures, tests, and cross-language ports that must reproduce Java behavior.

The string hello returns signed decimal 99162322 and hexadecimal 05e918d2. Java hashes UTF-16 code units rather than Unicode code points or UTF-8 bytes, so supplementary characters contribute their surrogate pair as two steps. That detail explains many mismatches with byte-oriented hashes even when both tools display the same visible text.

Remember that hashCode is a runtime contract, not security

Equal Java strings always share a hashCode, but different strings may legally collide; the famous collision pairs are a reminder that hashCode never proves identity. The computation stays in your browser. Do not use this value for passwords, signatures, tamper detection, or persistent security identifiers, and compare full strings whenever correctness depends on equality.