SSL/TLS certificate

TLS is the modern name for SSL; people still say SSL. A certificate lets browsers connect over HTTPS, so data between your visitors and your site is encrypted and the padlock shows. Without one, browsers warn visitors that your site is 'not secure'.

Basic certificates are free from Let's Encrypt, a non-profit, and most hosts install one automatically and renew it for you.

Example: you move yourbusiness.co.uk to a new host. The new host issues a free certificate once your domain points at it, so the site is on HTTPS from day one. If the certificate isn't set up, visitors see a browser warning instead of your home page.

Paid certificates exist, including ones that check your organisation's identity, but browsers show the same padlock for free and paid certificates, so most sites don't need to pay.

What it means for your price: treat a free, auto-renewing certificate as standard. If a host charges for SSL, or adds it pre-ticked at checkout, count that cost in the true 3-year cost or look elsewhere.

How to check yours: click the padlock in your browser's address bar to see who issued the certificate and when it expires.