Inspecting a flags integer
A permissions or feature-flags value shown in binary reveals exactly which bits are set, which decimal hides.
Decimal to Binary
Convert a decimal number to binary in your browser, with full precision for large values.
Maintained by Roshan.
Use Decimal to Binary
Converts decimal number to binary in this tab, with nothing sent anywhere.
Runs entirely on your deviceThe conversion happens in this browser tab. Nothing you type is uploaded, logged or stored, which is worth knowing for anything you would not paste into a search box.
Explore developer and data tools
Find related browser-local tools for nearby tasks without starting another search.
Browse all developer and data toolsAbout Decimal to Binary
Converting a decimal number to binary is where people first meet how computers count, and it stays useful well beyond the classroom, for anyone working with bit flags, masks and low-level protocols. Binary makes the individual bits of a number visible, which is exactly what you need when a value is really a set of on-off switches packed together - a permissions field, a hardware register, a feature-flags integer. As with the other base conversions, the accuracy of large numbers is the thing amateur converters get wrong, because they route through a floating-point value that cannot hold every large integer exactly. This tool uses arbitrary-precision integers, so a number of any size converts to its exact binary representation, every bit correct.
Using Decimal to Binary
- The number is read as an arbitrary-precision integer, so no size limit silently truncates or rounds it.
- It is converted to base two by repeated division, producing the bits from least to most significant and assembling them in order.
- The output is the pure binary value, with no byte grouping, since it represents a single number rather than a stream of bytes.
- Leading zeros, spaces and separators in the input are tolerated.
- Zero converts to a single zero, and the conversion is exact regardless of length.
Where decimal to binary helps
Teaching place value in base two
Convert a familiar decimal number and the bits show how base two builds the same value from powers of two.
Before you use the result
- This converts a number to binary, which is different from encoding text as binary - the text tool groups bytes; this shows a value's bits.
- Only whole numbers convert; binary fractions are not produced.
- Negative numbers depend on a chosen bit width for two's-complement, so enter the magnitude here.
- The binary of a large number is long, which is inherent to the base.
- It is a representation, not encryption.
Questions about Decimal to Binary
How is this different from text to binary?
This converts a number to its binary value. Text to binary encodes characters as UTF-8 bytes and groups them. Different jobs.
Does it stay exact for big numbers?
Yes, thanks to arbitrary-precision integers. No large value is rounded.
Can it do fractions?
No, only whole numbers.
Why would I want binary of a number?
To see individual bits - useful for flags, masks and low-level work where a number is really a set of switches.
Is the number sent anywhere?
No. The conversion is done in this tab.
Related tools
Binary to Decimal
Convert a binary number to decimal in your browser, with full precision for large values.
Decimal to Hex
Convert a decimal number to hexadecimal in your browser, with full precision for large values.
Text to Binary
Convert text to binary in your browser. Each character becomes its UTF-8 bytes, grouped for readability.