No limits to how many characters. Just uppercase and lowercase are the same cause scratch is dumb and it can't tell da difference. If you want to learn binary then... Here we go...... An example of binary is that the letter A's number is 65 and its number is also called its decimal, so to turn 65 to binary you have to divide it by two, and find its remainder so 65 / 2 = 32 R 1, so because its remainder is 1, the first is one, now, because you also got 32, you divide 32 by 2 so 32 / 2 = 16 R 0, so the next, is 0, and reapeat until you get 0. 65 / 2 = 32 R 1 32 / 2 = 16 R 0 16 / 2 = 8 R 0 8 / 2 = 4 R 0 4 / 2 = 2 R 0 2 / 2 = 1 R 0 1 / 2 = 0 R 1 If you look at the remainders, you get 1000001 Then you flip that, now you get 1000001 Then add zeros before the first number until the length of the number is 8 so now you get 01000001 So the binary code of A is 01000001 Thats just for one letter, but if you want, you can write sentences! Or words. But make sure you add dashes or spaces between binarys. If you want to know more decimals of letters/numbers/symbols/Literally any character, check out the Ascii table, aka the "American Standard Code for Information Interchange" from this link: https://www.bing.com/images/search?view=detailV2&ccid=yI4dQHgj&id=F5B9E09BFC85F64352D80ADF62D0AC367E6E0348&thid=OIP.yI4dQHgjDXNEIvuN3BWYtwHaE7&mediaurl=https%3a%2f%2fupload.wikimedia.org%2fwikipedia%2fcommons%2fthumb%2f1%2f1b%2fASCII-Table-wide.svg%2f1280px-ASCII-Table-wide.svg.png&cdnurl=https%3a%2f%2fth.bing.com%2fth%2fid%2fR.c88e1d4078230d734422fb8ddc1598b7%3frik%3dSANufjas0GLfCg%26pid%3dImgRaw%26r%3d0&exph=851&expw=1280&q=ascii+table&simid=608035363861703392&FORM=IRPRST&ck=14CF463A34F40E912CF1F69184FC2E97&selectedIndex=0&itb=1&adlt=strict&ajaxhist=0&ajaxserp=0