How do you convert hex FF to decimal?

FF in hexadecimal equals 255 in decimal. Each hex digit represents a power of 16: F (which equals 15) in the 16s place gives 15 times 16 = 240, and F in the 1s place gives 15. Adding them: 240 + 15 = 255. You can also use parseInt('FF', 16) in any programming language to get 255 directly.

Why is binary used in computers?

Computers use binary because digital circuits naturally represent two stable states: high voltage (1) and low voltage (0). All data, whether numbers, text, images or instructions, is ultimately stored and processed as combinations of these binary digits. Groups of 8 bits form a byte, and all higher-level data types are built from bytes.

What is the fastest way to convert binary to hex?

Group the binary digits into sets of four from right to left, padding the leftmost group with zeros if needed. Each group of four bits maps to exactly one hex digit: 0000=0, 0001=1, ..., 1001=9, 1010=A, 1011=B, 1100=C, 1101=D, 1110=E, 1111=F. For example, 11111111 groups as 1111 1111, which is FF.

Binary Hex Octal Decimal Converter

This converter lets you type a number in any of the four most common positional number systems and see the equivalent in all three other bases instantly. Type in the binary field and the decimal, hexadecimal, and octal fields update in real time. Type in the hex field and the others follow. The same works for octal and decimal. Binary (base 2) uses only the digits 0 and 1 and is the native language of digital hardware. Hexadecimal (base 16) uses digits 0 through 9 and letters A through F, and is widely used in programming, colour codes, memory addresses, and checksums because each hex digit represents exactly four binary bits, giving a compact shorthand for long binary strings. Octal (base 8) uses digits 0 through 7 and appears in Unix file permission codes and some legacy computing contexts. Decimal (base 10) is the everyday number system most people use. The converter uses JavaScript's parseInt to parse each input in its respective base, then uses toString to convert to the other three bases. Hexadecimal output is shown in uppercase. The binary field accepts only 0s and 1s; the octal field accepts 0 through 7; the hex field accepts 0 through 9 and A through F (case-insensitive). Invalid characters are ignored and the remaining valid digits are parsed. This tool is useful for programming students learning base conversion, developers debugging bitwise operations, network engineers reading MAC addresses and IPv6 in hex, and system administrators writing chmod commands in octal. The converter handles non-negative integers only; it does not support negative numbers or fractional values in any base.

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Hexadecimal (base 16)

Decimal (base 10)

Binary (base 2)

Octal (base 8)

255

decimal value

HexFF

Binary11111111

Octal377

How it works

When you type in any field, the converter reads the value from that field and calls parseInt(value, base) to convert it to a JavaScript integer. It then calls (n).toString(2), (n).toString(8), (n).toString(10), and (n).toString(16) to populate all four output fields and the results card. To prevent update loops, the converter temporarily removes event listeners from the other three fields while updating them, then reattaches them after. Hexadecimal values are displayed in uppercase. Numbers above 2^53 - 1 may lose precision due to JavaScript using 64-bit floating-point representation.

Worked example

Enter FF in the hexadecimal field: parseInt('FF', 16) = 255. Converting 255 to binary gives 11111111. Converting to octal gives 377. The decimal value is 255. These match the default values pre-filled in all four input fields above.

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Data Storage Converter: convert bits, bytes and larger storage units.
Percent Error Calculator: verify the accuracy of a converted value against an expected result.

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