# Parity Calculator (Even or Odd Number)

URL: https://speedycalculator.com/calculators/other/parity/
Last updated: 2026-10-30

> The parity calculator tells you whether a number is even or odd in decimal, binary, hexadecimal or octal, and also gives its bit parity – whether its binary form contains an even or odd number of 1s. Enter several numbers to get a table.

## Inputs

- Type of parity
- Number base
- Number(s)

## Results

- Result
- The number is
- Bit parity
- Last digit
- Decimal value
- Binary
- Number of 1 bits
- Even-parity bit for this value
- All numbers

## Formula

```
Number parity: n is even if n mod 2 = 0 (last binary digit 0; last decimal digit 0, 2, 4, 6, 8)
Bit parity: even if the count of 1s in binary is even
```

## Explanation

The word parity has two related meanings. In mathematics, the parity of an integer is whether it is even or odd: divisible by 2 or not. In base 10 you only need the last digit (0, 2, 4, 6 or 8 means even), and the same shortcut works in any even base – in binary a number is even exactly when its last bit is 0, and in hexadecimal when its last digit is 0, 2, 4, 6, 8, A, C or E. Zero is even, and so are negative numbers like −4.

In computing and communications, parity usually means something else: whether the binary representation contains an even or odd number of 1 bits. That bit parity is what parity bits, checksums and the x86 parity flag are based on, and it is independent of whether the number itself is even. For example, 201 is an odd number, but in binary it is 11001001, which has four 1s – even bit parity.

The calculator gives both answers for the number you enter, together with its decimal and binary forms, the number of 1 bits and the parity bit that would make it even. Arbitrarily long numbers are supported, and several numbers can be checked at once.

### How to use the Parity Calculator

- **Type of parity**
- **Number base**
- **Number(s)**

Everything is calculated in your browser, so results appear instantly and nothing you type is sent to a server.

### How it works

The input is read as a whole number in the chosen base (any length). Number parity comes from the remainder after division by 2; bit parity from counting the 1s in the binary representation.

### Worked example

Take the number **201**. Its last decimal digit is 1, so it is an **odd number**. In binary it is 11001001, whose last bit is also 1. Counting the 1 bits gives four, so its bit parity is **even** and an even-parity bit for it would be 0. With the default input 1101 read as decimal, the number is odd (last digit 1) and its binary form 10001001101 has five 1s – odd bit parity.

### Even digits in each base

BaseA number is even when its last digit is2 (binary)08 (octal)0, 2, 4, 610 (decimal)0, 2, 4, 6, 816 (hex)0, 2, 4, 6, 8, A, C, E

## Worked example

Inputs — Type of parity: Number parity (even or odd number); Number base: Decimal (base 10); Number(s): 1101.

Results — **Result = Odd number**; The number is = Odd; Bit parity = Odd; Last digit = 1; Decimal value = 1101; Binary = 10001001101.

## Key terms

- **Parity (of a number)**: Whether an integer is even or odd.
- **Bit parity**: Whether the binary representation contains an even or odd number of 1s.
- **Least significant bit**: The rightmost bit; it alone decides whether a binary number is even.

## FAQ

**Is zero even or odd?**
Even – 0 divided by 2 leaves no remainder.

**How can I tell if a binary number is even?**
Look at the last bit: 0 means even, 1 means odd.

**Is a hex number ending in B even?**
No. B = 11 is odd; hex numbers are even when they end in 0, 2, 4, 6, 8, A, C or E.

**What is the difference between number parity and bit parity?**
Number parity asks whether the value is divisible by 2; bit parity asks whether its binary form has an even number of 1s. 201 is odd but has even bit parity (11001001 has four 1s).

**Are negative numbers even or odd?**
The same as their absolute value: −7 is odd, −8 is even.

**What is the parity of 1101?**
As a decimal number 1101 is odd. Read as binary it is 13, also odd, with three 1 bits – odd bit parity.


## Sources

- [Wikipedia – Parity (mathematics)](https://en.wikipedia.org/wiki/Parity_(mathematics))
- [Wikipedia – Parity bit](https://en.wikipedia.org/wiki/Parity_bit)