Numbers & Notation
Every numbers & notation calculator on CalcEngines — unit converters, derived indices and interpretive tools, each with its formula, a worked example and the reference intervals it is judged against.
6 calculators in this section
- Aspect Ratio Calculator (Resolution, Letterbox, Named Ratios)Reduce any resolution to lowest terms with a real greatest common divisor, find the nearest named ratio with its error, and size the letterbox bars. 1366×768 is 683:384 — and “21:9” is three different shapes, none of them 21:9.
- Hex to RGB Converter — with HSL, Relative Luminance and WCAG ContrastPaste a hex colour and get R, G and B, the HSL triple, the sRGB relative luminance, and the WCAG 2 contrast ratio against white and against black — with the AA and AAA thresholds for normal and large text shown as bands. Three-digit shorthand and a missing hash are both accepted.
- Inch Fraction Converter (Decimal and mm to 1/16, 1/32, 1/64)Decimal inches or millimetres to the nearest fraction on a tape measure, with the residual printed in thousandths of an inch and in millimetres so you can decide whether it matters. Whole inches, numerator and denominator come out as separate numbers, reduced to lowest terms — and feet and inches go in as well as out.
- kB vs KiB Converter — Why 1 TB Shows as 931 GBDecimal kB, MB, GB, TB against binary KiB, MiB, GiB, TiB, with bits in the same ladder and a transfer time. A 1 TB drive is 931.32 GiB — and Windows prints that number labelled “GB”, which is the whole of the confusion.
- Number Base Converter — Binary, Octal, Decimal, Hex, Any Base 2 to 36Type a number in any base from 2 to 36 and read it back in any other, with the bit width, the byte count and the smallest standard integer that holds it. Integers above 9,007,199,254,740,991 are refused rather than rounded, and a digit the base does not have is refused rather than guessed.
- Roman Numeral Converter (Both Ways, 1 to 3999)Type a number and get the numeral; paste a numeral and get the number. The card splits the answer into its place values, each one as a numeral and as a number — 1994 is M + CM + XC + IV, which is 1000 + 900 + 90 + 4 — and refuses anything that is not strict classic form, because IIII is not four and IC is not ninety-nine. All 3,999 numerals from I to MMMCMXCIX are covered, and nothing above 3,999 is faked: that needs an overline, which plain text cannot draw.