All calculators, generators and converters

Rolls from the room perimeter, allowing for pattern repeat and trimming waste.

Tiles and boxes by area, with an allowance for cuts and grout lines.

Litres and cans from wall area, coverage per m² and number of coats.

Three modes: percent of a number, share and percentage change.

Five kinds of quantity and dozens of units, temperature included.

A random password with character-set options and an entropy estimate.

Monthly payment, interest paid and the total cost of the loan.

Random whole numbers in batches, with no repeats, sorting and stats.

Heads or tails: one flip or a series, with the results counted.

Dice from d4 to d20, with the total, breakdown and range, up to 100 at once.

A winner from your list, with or without repeats.

Checks a number against the classic equal-halves rule.

Your own options, weights, odds and win history on one wheel.

UUID v4, v7 and v1 in batches of up to 1,000, with formats and encodings.

Checks the format, version and variant, and explains any error.

Shows the version, variant, fields and creation time of v1, v6 and v7.

26-character sortable IDs: a timestamp plus 80 random bits.

Short URL-safe IDs with a configurable length and alphabet.

Body mass index and its WHO category, with the formula.