Free online tools & calculators that just work
Income tax for the US, UK and India, mortgage, EMI, SIP, GPA, BMI, image resizer, QR codes and more. Every tool runs in your browser, shows its formula and explains the result in plain words.
- 63Free tools
- 10Categories
- 0Signups needed
- 100%In-browser
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Why people use MasterKit Online
Instant results
Answers update as you type. No page reloads, no waiting.
Private by design
Your numbers, text and photos are processed on your own device.
Formulas you can check
Each tool shows the formula, a worked example and its sources.
Built for US, UK & India
Current IRS brackets, HMRC rates, Indian tax regimes, GST 2.0, stamp duty and $, £, ₹ currency switching.
Works everywhere
Fast on phones, tablets and desktops, even on slow connections.
Kept up to date
We review tools when laws, tax rates or admission rules change.
Frequently asked questions
Are all the tools really free?
Yes. Every tool is free with no signup, no daily limit and no watermark on downloads.
Is my data safe?
Calculators, text tools and image tools run entirely in your browser. Your files and numbers are not uploaded to our server. The only exception is the YouTube Thumbnail Downloader, which fetches the public thumbnail from YouTube for you.
Which tax years do the tax calculators use?
The US Income Tax Calculator 2026 uses the IRS 2026 brackets, the UK Take-Home Pay Calculator 2026/27 uses 2026/27 HMRC rates, and the Income Tax Calculator India FY 2026-27 uses FY 2026-27 slabs for both regimes.
Can I change the currency?
Yes. Use the $ / £ / ₹ / € switch in the top bar. Money tools such as the Loan EMI Calculator and Compound Interest Calculator update instantly, and your choice is remembered.
Do the tools work on mobile?
Yes. Every page is designed mobile-first and works on Android and iPhone browsers.
Can I suggest a new tool?
Yes, please do. Send your idea through the contact page. We add new tools every month.