Decimal to Binary

About This Tool

Decimal to Binary is a free daily-quota online decimal to binary converter that requires no installation and no registration — ready to use in seconds. Enter decimal or binary numbers and convert them in both directions with a single click, with support for one-per-line batch conversion, copy and download. All processing is done locally in your browser for 100% privacy — your data is never uploaded to any server. Whether you are calculating IP addresses, learning computer fundamentals or debugging code, this tool delivers accurate, professional-grade results effortlessly.

How to Use

1. Enter numbers

   Type decimal or binary numbers in the left input box, one per line. Negative numbers and the 0b prefix are supported

2. Pick direction

   Click the "Decimal → Binary" or "Binary → Decimal" button and the conversion happens automatically

3. View result

   Results are shown line by line in the right text box. Use the "Copy" or "Download" button to save them

Use Cases

• IP address math: quickly switch between decimal and binary when working with subnet masks and network address conversion
• Learning fundamentals: verify conversions while studying data storage, bitwise operations, sign-magnitude and two's complement
• Development debugging: quickly convert memory addresses and data sizes while writing programs to boost productivity

Key Advantages

1. Free Daily Quota

   Every day you get free usage, which is enough for light everyday needs at zero cost. Frequent or professional users can unlock higher quotas with a membership

2. Privacy Safe

   All conversions run locally in your browser — data is never uploaded to any server, so sensitive content stays completely private

3. No Install, No Sign-up

   Open the page and start converting right away — no software to download and no account to register

4. Batch Conversion

   Convert one value per line in batch; invalid lines are flagged individually without affecting the other results

5. Negative Numbers

   Both directions support negative input — negative binary results are shown in two's complement form, meeting low-level development needs

6. Works on All Devices

   Runs smoothly on desktop, mobile and tablet — just open your browser, regardless of operating system

Common Value Reference

Here are the decimal-binary pairs used most often in development, so you can quickly grasp the conversion pattern:

Decimal	Binary	Note
1	1	2 to the power of 0
2	10	2 to the power of 1
4	100	2 to the power of 2
8	1000	2 to the power of 3
16	10000	2 to the power of 4
32	100000	2 to the power of 5
64	1000000	2 to the power of 6
128	10000000	2 to the power of 7
255	11111111	Maximum value of an 8-bit binary number

Negative Numbers and Two's Complement

In computers, integers are usually stored in two's complement form. This tool supports negative numbers: binary input may carry a minus sign, and negative decimal values are output as two's complement (32-bit).

Understanding two's complement helps you grasp how integers are stored in a computer. For example, in a 32-bit system, -1 is represented as 32 ones — counterintuitive at first, yet the standard design of modern computers.

FAQ