About Online CalcKit
Free, fast, mobile-friendly calculators for everyday questions about money, work, home, dates, and health — tailored to the UK, the United States, and Europe.
What we do
Online CalcKit is a hub of 25 practical calculators across five categories: Money, Business, Home, Date & Time, and Health & Fitness. Each calculator is built around a clear question — "how much will my savings grow?", "how many days until this deadline?", "how much paint do I need?" — and gives a plain-English answer alongside the raw number.
The site supports three regional contexts: the United Kingdom (pounds, UK conventions), the United States (dollars, US conventions including sales tax), and the European Union (euros, with member-state-aware notes where relevant). Pick your region from the home page or the header at any time; your choice is saved locally so you don't see it again.
Why we built this
Most calculator sites either bury the answer under ads, or skip the explanation entirely and leave you with a number you can't interpret. We wanted a site that respects your time, gives a clear figure, explains what it means in plain English, and runs cleanly on a phone.
Every calculator is unit-tested against worked examples, and every result page explains the formula, common pitfalls, and how the answer might differ in real-world conditions (taxes, fees, rounding, regional variations). The goal is a tool you can trust for rough planning, not a substitute for professional advice.
Who we are
Online CalcKit is owned and operated by AI Regenesis Ltd, a private limited company registered in England and Wales (company number 16376961) with its registered office at 20 Wenlock Road, London, N1 7GU.
AI Regenesis is a small UK technology company. You can find more about our other work at ai-regenesis.com.
Get in touch
Spotted an error in a calculation, have a suggestion for a calculator we should add, or want to report a bug? Email us at bryan@ai-regenesis.com or visit the Contact page for full details.
Important disclaimer
The calculators are general-purpose estimation tools. They do not constitute financial, legal, medical, tax, or professional advice. For decisions with real-world consequences, consult a qualified adviser in the relevant field. Full Terms of Use apply to your use of this site.