Number Converter
Convert numbers between bases
100% free. Runs entirely in your browser - your files and data never leave your device and nothing is uploaded to any server.
About this tool
Convert numbers between different number bases - binary, octal, decimal, and hexadecimal - useful for programming, computer science studies, or any context where you need to translate a value from one base to another.
How to use this tool
- Choose input baseSpecify whether value is binary, octal, decimal, or hexadecimal.
- Enter source valuePaste number exactly using valid symbols for selected base.
- Convert to target basesGenerate equivalent representations across supported systems.
- Use output in workflowApply converted values in debugging, networking, or embedded tasks.
How to convert binary to decimal by hand
Each binary digit is worth twice the one to its right: from the right, 1, 2, 4, 8, 16 and so on. Add the values where there is a 1: 101101 is 32 + 8 + 4 + 1 = 45. Octal groups bits in threes (45 is 55 in octal) and hexadecimal in fours (45 is 2D).
To convert decimal to binary, divide by 2 repeatedly and read the remainders from bottom to top.
Key features
- Saves manual base-conversion time and arithmetic mistakes.
- Helps students and developers understand numeral systems.
- Useful for low-level programming and protocol debugging.
- Provides quick cross-base verification in one place.
Common uses
- Converting hex values while debugging memory/register data.
- Translating binary numbers in CS coursework.
- Validating bitmask and permission flag calculations.
- Checking firmware or networking configuration values.
Tips for better results
- Check prefixes (`0x`, etc.) and remove unsupported symbols if needed.
- Use uppercase hex output for readability in docs.
- Validate signed/unsigned assumptions before interpreting negatives.
- Cross-check critical values in decimal for human sanity.
Mistakes to avoid
- Entering digits invalid for the selected base.
- Confusing octal and decimal literals in code contexts.
- Assuming negative-value representation is always two’s complement.
- Dropping leading zeros when fixed-width binary matters.
Frequently asked questions
Typically binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16) - the most commonly used bases in computing and mathematics.
Support depends on how negative values are represented in the target base (like two's complement for binary) - check the tool's specific handling if you're working with signed numbers.
They serve a similar purpose - if you specifically need hex/decimal/binary conversion in a developer context, either tool works; this one is positioned as a general math conversion utility.
Write the place values from the right - 1, 2, 4, 8, 16 and so on - and add those where the digit is 1. 101101 is 32 + 8 + 4 + 1 = 45.
Mainly in Unix file permissions: chmod 755 means rwx for the owner and r-x for group and others, with each octal digit standing for three permission bits.
Electronic circuits are most reliable with two clear states - on and off - so everything is stored as bits. Hexadecimal and octal are just shorter ways for people to write those bits.