Here's what I have as a reference. Basically a summary of the Format Specification Mini-Language . This would all go after a : in the f-string curly braces. So if you want a float with 2 decimal place precision, with * as fill and right aligned in a field width of 10 characters you'd do f"{val:*>10.2f}" [[fill]align][sign][#][0][minimumwidth][.precision][type] Fill: Add a character to fill with. Must be followed by Align flag. Align: '<' - Forces the field to be left-aligned within the available space (This is the default.) '>' - Forces the field to be right-aligned within the available space. '=' - Forces the padding to be placed after the sign (if any) but before the digits. This is used for printing fields in the form '+000000120'. This alignment option is only valid for numeric types. '^' - Forces the field to be centered within the available space. Sign: '+' - indicates that a sign should be used for both positive as well as negative numbers '-' - indicates that a sign should be used only for negative numbers (this is the default behavior) ' ' - indicates that a leading space should be used on positive numbers #: Flags alternate numbering formats; binary, octal, and hexadecimal output will be prefixed with '0b', '0o', and '0x', respectively. 0: Zero-padding. Equivalent to fill '=' and character of '0' Minimumwidth: Min width of the field. Precision: Decimal places for floats or max field size for non-numeric types. Type: Integers: 'b' - Binary. Outputs the number in base 2. 'c' - Character. Converts the integer to the corresponding Unicode character before printing. 'd' - Decimal Integer. Outputs the number in base 10. 'o' - Octal format. Outputs the number in base 8. 'x' - Hex format. Outputs the number in base 16, using lower- case letters for the digits above 9. 'X' - Hex format. Outputs the number in base 16, using upper- case letters for the digits above 9. 'n' - Number. This is the same as 'd', except that it uses the current locale setting to insert the appropriate number separator characters. '' (None) - the same as 'd' Floats: 'e' - Exponent notation. Prints the number in scientific notation using the letter 'e' to indicate the exponent. 'E' - Exponent notation. Same as 'e' except it converts the number to uppercase. 'f' - Fixed point. Displays the number as a fixed-point number. 'F' - Fixed point. Same as 'f' except it converts the number to uppercase. 'g' - General format. This prints the number as a fixed-point number, unless the number is too large, in which case it switches to 'e' exponent notation. 'G' - General format. Same as 'g' except switches to 'E' if the number gets to large. 'n' - Number. This is the same as 'g', except that it uses the current locale setting to insert the appropriate number separator characters. '%' - Percentage. Multiplies the number by 100 and displays in fixed ('f') format, followed by a percent sign. '' (None) - similar to 'g', except that it prints at least one digit after the decimal point. Answer from ebdbbb on reddit.com