Number-base guide: binary, octal, decimal and hexadecimal

When this tool helps

Binary, octal, decimal and hexadecimal are different ways to write the same whole number. The input base tells the tool how to interpret the digits; the output base tells it how to display that integer. A leading minus sign is kept as a sign, not converted into a machine-width bit pattern.

Select both bases before entering the whole number. Use only digits that are valid in the input base, with no 0x or 0b prefix and no decimal point. Integer arithmetic preserves values beyond ordinary floating-point precision.

What to enter

These are the candidate Android fields, not a form on this website. Editable fields in the app start empty; modes and units are selected separately.

Input base: Binary (2), Octal (8), Decimal (10) or Hexadecimal (16).
Output base: One of the same four supported bases.
Whole number · no 0x or 0b prefix: Up to 128 digits plus an optional leading sign.

Worked example · not prefilled app data

Try this example after the update is available

The values below explain the calculation. They are not a quote, a live measurement or an automatic answer for your situation.

Input base: Decimal (10)
Output base: Hexadecimal (16)
Whole number: 255

Checked example resultFF

255 is fifteen sixteens plus fifteen ones. Hexadecimal writes the digit fifteen as F, so the result is FF.

Formula and assumptions

Interpret input digits by positional base value, then express the same signed integer in the selected output base

Only whole numbers are supported. Hexadecimal output is upper case.
Negative results use a leading minus sign, not a fixed-width two’s-complement encoding. There is no byte order or signed-width setting.

A common mistake to avoid

Do not type 0xFF when Hexadecimal is selected; enter FF. A binary input containing 2 is rejected because 2 is not a binary digit.

Find this tool in the Android update

When you have the redesigned Android update, open Tools and search for Number base converter, or find it under Numbers.
Open the tool, choose the mode or units relevant to your task, then enter your own values.
Review the result and explanation. Use Calculate & save only if you want the calculation kept in local History; Copy result does not send it to our server.

This guide is an educational preview of the update in testing, not an announcement that Google Play has approved or published it. Calculations are in the native app; no web calculator or download is offered on this page.

Questions about Number base converter

Can I convert negative integers?

Yes. A value such as decimal −10 converts to binary −1010, with a leading minus sign.

Can this convert fractional values or two’s-complement bytes?

No. This candidate supports signed whole-number notation only, without fractional digits, fixed widths or two’s-complement encoding.