ASCII and character codes

Type text to get its character codes, or swap the boxes and paste a list of numbers to read them back as text.

Base switches the output between decimal, hexadecimal and octal, and decoding expects whichever base you've picked. Separator sets what goes between the numbers. With None, every number is padded to two hex digits or three decimal or octal ones, so the run can be cut apart again. A token that isn't a valid number in the chosen base gets named in the error rather than skipped.

ASCII gave the first 128 characters a number each: control codes below 32, then punctuation, the digits, and the two alphabets. Those numbers never moved. Unicode adopted them wholesale, so 65 is still A on every machine you'll meet.

Past 127 you're in Unicode proper. This converter reports code points, so an accented e is 233 and most emoji are six-digit numbers, like 128,512 for the grinning face. For the bytes underneath, use binary.

ASCII was first published in 1963 for machines that printed on paper. Lowercase arrived in the 1967 revision, each letter exactly 32 after its capital. That's one bit, and the committee put it there because it made keyboards and printers simpler to build. The digits start at 48, and masking off the top four bits leaves the digit's actual value behind.

Carriage return, 13, threw the print head back to the left margin. Line feed, 10, rolled the paper up a line. Two separate physical actions. Windows still ends a line with both, Unix with one, and a file moved between them can arrive with every line stacked in the same spot. Escape, 27, outlived the machine it was built for and is still on your keyboard.

Unicode code points carry these same numbers on past 127, and binary shows the bits each one is stored as.

Base64 sits a level up, packaging those bytes for travel.