How to Add This to Your Website
1
Choose your height and theme above — light works best on white/light sites, dark on dark-background sites.
2
Click Generate to create your personalised embed code.
3
Click Copy Embed Code and paste it into your website HTML — on an accounting page, business tools page or contact page.
4
Done. Visitors can now validate VAT numbers directly on your site without leaving the page.
Frequently Asked Questions
Who is this widget for?
Any UK business website, accounting firm, bookkeeper, or any site serving business owners. It's particularly useful for accounts pages, supplier onboarding forms, and invoice checking.
Does it need an API key?
No — the widget calls the HMRC API directly from the visitor's browser. You don't need to set up anything on your server.
What does a valid check show?
The business name and registered address as held by HMRC. This is the officially registered information, which may differ from trading names.
Is it always accurate?
The data comes directly from HMRC's register in real time. It's as accurate as HMRC's own records.
Is it free?
Yes, completely free. A small "Full tool · Calcify" attribution link is included — please don't remove it.