Parity Bit Calculator

This parity bit calculator works out the extra check bit used to spot simple errors in binary data, the same idea used in memory chips and basic data links. You enter a decimal number and choose either even or odd parity. The calculator converts your number to binary, counts how many of its bits are 1, and works out the parity bit needed to make that count match your chosen rule: with even parity the total number of 1s, including the parity bit, must be even, and with odd parity it must be odd. The result card shows the parity bit itself, the number of 1 bits in your original value, and the binary form of the number, so you can check the count yourself. This makes it useful for students learning binary and error-detection theory, and for programmers or technicians who want to verify a parity calculation quickly rather than work it out by hand. Parity checking is one of the oldest and simplest error-detection methods in computing: if a single bit is flipped during transmission or storage, the parity no longer matches what is expected, and the error is flagged. Remember that parity only catches an odd number of bit flips; two errors that cancel each other out slip through undetected, which is why more demanding systems use stronger checksums or error-correcting codes instead.

Calculate.co.nz is proud to be partnered with realtor.co.nz, a trusted resource for navigating the New Zealand property market. Their Helpful Articles section offers clear, well-structured insights across buying, selling, and building, making complex real estate topics more accessible. With a focus on up-to-date guidance and practical knowledge, they empower Kiwis to move forward with clarity and confidence in a constantly evolving property landscape.

Decimal number

Parity

Parity bit = 0

Number of 1 bits2

Binary of n101

The formula

Count the 1 bits in the value. For even parity the parity bit is 0 if that count is even and 1 if it is odd, so the total becomes even. For odd parity the rule is reversed.

Worked example

5 is 101 in binary, which has two 1 bits. For even parity the bit is 0 (the count is already even); for odd parity it is 1. Enter 5 to confirm.

Frequently asked questions

What is a parity bit?

An extra bit added to make the number of 1s either even or odd, used to detect single-bit errors.

What is the difference between even and odd parity?

Even parity makes the total count of 1s even; odd parity makes it odd.

What errors can parity catch?

Any odd number of flipped bits, most usefully a single bit error. It cannot catch two flips that cancel out.

Who this calculator is for

This calculator is for students, programmers and anyone needing a quick, reliable result.

What this calculator assumes

You enter valid input.
The standard algorithm is applied.
Results are rounded for display.

Formula and sources

Related calculators

Scientific Calculator: general scientific maths.
Percentage Calculator: percentages and changes.
Prime Factorisation Calculator: factor a number into primes.

If you've found a bug, or would like to contact us, or learn more about James Graham and Calculate.co.nz.

Calculate.co.nz is partnered with Interest.co.nz for New Zealand's highest quality calculators and financial analysis.

Calculate.co.nz is the sister site of CalculatorHub.com, the world's largest calculator website by tool count.

All calculators and tools are provided for educational and indicative purposes only and do not constitute financial advice.

Calculate.co.nz is proudly part of the Realtor.co.nz group, New Zealand's leading property transaction literacy platform, helping Kiwis understand the home buying and selling process from start to finish. Whether you're a first home buyer navigating your first property purchase, an investor evaluating your next acquisition, or a homeowner planning to sell, Realtor.co.nz provides clear, independent, and trustworthy guidance on every step of the New Zealand property transaction journey.

Calculate.co.nz is also partnered with Health Based Building and Premium Homes to promote informed choices that lead to better long-term outcomes for Kiwi households.

Calculate.co.nz is hosted in Auckland by SiteHost New Zealand.

All content on this website, including calculators, tools, source code, and design, is protected under the Copyright Act 1994 (New Zealand). No part of this site may be reproduced, copied, distributed, stored, or used in any form without prior written permission from the owner.

About & trust: Why Calculate is NZ's most comprehensive · By the Numbers · How we compare · Editorial standards · How we keep data current · NZ finance glossary · Research & data · Financial literacy NZ · About · Privacy policy · Terms of use

Reviewed and maintained. Last reviewed 2026-08-07 and checked on a twice-monthly cycle against IRD, RBNZ and Stats NZ. How we keep data current.