Mozilla Firefox vs Opera

Mozilla Firefox: what it's good at

Firefox is the last major browser not built on Google's Chromium engine, developed by the non-profit Mozilla Foundation. It offers strong tracking protection on by default, deep customisation, and genuinely excellent built-in developer tools.

• Independent Gecko rendering engine
• Enhanced tracking protection by default
• Extensive extension ecosystem
• First-class developer tools

Opera: what it's good at

Opera bundles features that are usually add-ons elsewhere: a free built-in VPN, an ad blocker, a battery saver and integrated messengers in the sidebar. It is Chromium-based, so site compatibility matches Chrome.

• Free built-in VPN
• Integrated ad blocker
• Sidebar messengers and workspaces
• Battery saver mode for laptops

Which should you choose?

Both are free, so the honest answer is that you can install either and decide for yourself — that is the advantage of free software over a paid trial.

Both run on Windows, macOS, Linux, Android, iOS. If open source matters to you, Mozilla Firefox publishes its source code and Opera does not.

We deliberately do not publish a star rating for either. We have no way to verify a rating that would be honest at scale, and an invented one would be worse than none — so we give you the facts and let you decide.

Frequently asked questions

Is Mozilla Firefox better than Opera?

Neither is universally better. Mozilla Firefox the major independent browser, built by a non-profit, while Opera feature-packed browser with a free built-in VPN. The right pick depends on your platform and workflow.

Are both really free?

Mozilla Firefox is open source and Opera is free. Both can be downloaded without paying.

Can I install both?

Yes. Since neither costs anything, installing both and comparing them on your own files is usually the fastest way to decide.