Convert integers between binary, octal, decimal and hexadecimal without rounding. Supports large and negative numbers, entirely in your browser.
● Your files stay yoursWhole numbers only. Use digits 0–9 and A–F as allowed by the input base. Up to 4,096 input characters.
Copy becomes available when a result is ready. Editing inputs or options clears the previous result.
Select the input and output bases, enter a whole number and choose Convert number. For example, decimal 255 becomes hexadecimal FF, binary 11111111 or octal 377. Try an example loads 255 and selects decimal to hexadecimal. Copy result copies only the converted number. Editing input or either base clears the previous result. Clear removes the numbers and keeps your selected bases.
Conversion uses exact integer arithmetic, including values above the usual JavaScript safe-integer range. A leading + or - is accepted. Optional 0b, 0o and 0x prefixes are recognized only for the selected binary, octal or hexadecimal input base, after the sign; hexadecimal letters are case-insensitive. Spaces around the number are ignored, but spaces inside it, separators, fractions and decimal scientific notation are not accepted. Use ASCII digits 0–9, not localized digits. Output has no prefix or grouping, uses uppercase A–F, removes leading zeros and writes negative zero as 0. Negative values keep a minus sign: this is not fixed-width two’s-complement or floating-point conversion. The 4,096-character input limit includes signs, prefixes and whitespace; output can be longer. Nothing is uploaded or stored.
