Developer Calculators
Password, IP subnet, base64 and developer tools.
About these calculators
Eleven developer utilities that run locally in the browser: base64 and URL encoding with proper multi-byte UTF-8 handling, binary and subnet maths with validation that rejects malformed input instead of computing nonsense, password generation via cryptographically sound randomness, and Ohm's-law or voltage-drop checks for hardware-adjacent work.
Local execution is a feature, not a limitation — tokens, internal hostnames and credentials typed here never reach a server. Encoding tools preserve exact bytes and report errors on invalid sequences rather than silently substituting replacement characters, the behaviour that corrupts data downstream.
Choosing the right calculator
Encoding and formats
Base64 encodes and decodes with URL-safe variant support; url-encode handles query-string component versus full-URI modes and round-trips duplicate keys correctly; both validate strictly so corrupted payloads fail loudly at encode-time, not mysteriously later.
Networks and numbers
Subnet computes CIDR ranges, masks and usable hosts with octet-level validation; binary converts across bases with digit caps preventing runaway exponents; bandwidth and download-time translate plan speeds into transfer realities.
Security and electronics
Password generates from character pools with unbiased rejection sampling — length and entropy shown, never stored. Ohms-law solves the V=IR triangle; voltage-drop sizes conductor runs; resistor decodes colour bands including tolerance bands.
Developer calculators we stand behind
Also available (11) — work in progress, not yet indexed
These calculators work but are still being checked for accuracy and sourcing, so they are not in search yet. They are free to use.