Simple tools. Clear answers.
Get the job done without making it complicated.
Calculate, convert, generate and check everyday information in your browser. When you need more than a result, our guides explain the maths and the practical details behind it.
Start here
Tools for jobs people actually need
A few useful starting points. You can find the rest of the collection on the tools page.
Percentage Calculator
Work out percentages, percentage change and common discount calculations.
Open tool →Unit Converter
Convert everyday measurements such as length, weight, temperature and more.
Open tool →QR Code Generator
Create a QR code for a website, text or other supported information.
Open tool →Invoice Generator
Prepare a clear invoice for a customer, client or small-business transaction.
Open tool →More ways to use the site
Choose a tool or learn how it works
Sometimes you only need the answer. Sometimes you need to know where the answer came from. KingToolsKit is built for both.
Why KingToolsKit?
Built for small tasks that still deserve a good answer
You should not need to install an application or create an account just to work out a percentage, convert a measurement, check a word count or make a QR code. Our public tools are designed to be straightforward, while the supporting guides give you enough context to use the result sensibly.
We also try to be honest about the limits of a calculator. A tool can do the arithmetic, but it cannot know every detail of your business, tax situation, contract or technical environment.
Good places to start
Latest guides
Learn something useful
Profit Margin vs Markup
Why the two percentages are different and how that affects pricing.
Read guide →How to Calculate Break-Even
A simple way to think about fixed costs, variable costs and sales targets.
Read guide →How to Test a QR Code
A practical checklist before you send a design to the printer.
Read guide →