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MeasureMate

Technology

Subnetting, color codes, hashes, QR codes and password strength. Everything runs in your browser, and nothing you type into these tools is uploaded.

Each page notes the relevant standard (RFC, CSS Color, FIPS) so you can check the behavior against the source.

5 tools · updated

Password Strength Calculator Estimate a password’s entropy in bits and how long an exhaustive search would take, computed in your browser without sending it anywhere. Network Calculator Calculate an IPv4 subnet from an address and CIDR prefix: network and broadcast addresses, subnet and wildcard masks, host range and host count. Color Converter Convert a color between HEX, RGB and HSL notation in the sRGB space, with a preview swatch. QR Code Generator Create QR codes for links, text, email, phone numbers and WiFi networks, drawn in your browser and downloadable as PNG or SVG. Hash Calculator Generate MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes of text, computed in your browser.

Notes on the standards behind these tools

Subnets: how many hosts fit?

A prefix length says how many leading bits name the network. A /24 has 256 addresses, of which 254 are usable for hosts once the network and broadcast addresses are set aside; each extra bit of prefix halves the block. Point-to-point /31 links (RFC 3021) and single-host /32 routes are the exceptions. The network calculator lists the mask, wildcard, range and host count for any IPv4 prefix.

How strong is a password, really?

Entropy grows with length times the size of the character set, but only when every character is chosen at random. A long password made of a dictionary word plus a year is far weaker than its length suggests, because attackers try those patterns first. The password strength calculator estimates entropy and brute-force time in your browser; a password manager generating random strings beats any clever pattern.

Which hash should I use?

To check that a download arrived intact, compare its SHA-256 with the one the publisher lists. MD5 and SHA-1 still catch accidental corruption but are broken against deliberate collisions, so do not rely on them for security. A hash is not encryption and cannot be reversed, and plain fast hashes are the wrong tool for storing passwords, which need a slow, salted algorithm such as Argon2 or bcrypt. The hash calculator computes MD5 and the SHA-1 and SHA-2 family locally.

QR codes and color codes

QR codes carry error correction at four levels, recovering roughly 7%, 15%, 25% or 30% of damaged modules; higher levels survive scratches and logos but need a denser code. The QR code generator lets you pick the level and formats WiFi, email and phone payloads the way phone cameras expect. HEX, RGB and HSL are three ways to write the same sRGB color, and the color converter moves between them.