How much does Lumo Plus cost?
The short answer
Lumo Plus costs €12.99 a month on monthly billing, or €119.88 a year when you pay annually, which works out to €9.99 a month. Proton sells it as Lumo AI Plus. We read these euro prices on 22 September 2026, and the free plan remains an option for occasional chats.
In detail
Paying yearly saves €36 compared with twelve monthly payments, which add up to €155.88. You pay the yearly amount upfront. Proton showed euro prices when we read the page from the Netherlands; the page has a currency switcher for CHF, EUR and USD, and we could only read the euro amounts.
What the money buys is mostly room. Proton says the free plan limits Max model usage, messages, chat history, image generations, projects and Custom Lumos. Lumo AI Plus offers unlimited chats, extended chat history, unlimited projects and Custom Lumos, more image generations and more use of the Max model.
Plus also lets you upload several large files at once, where the free plan handles individual small files. Web search is already part of the free plan.
Privacy is not what you pay extra for. On both plans your chats stay out of model training, saved conversations sit behind zero-access encryption that Proton cannot open, and nothing you type is tracked or profiled for ads.
Lumo AI Plus makes sense if you run into the free limits every week, keep long projects going, or want to work through several large documents at once. For a quick question now and then, the free plan is enough, and you can start without a Proton account.
Trying it carries little risk. Proton offers a 30-day money-back guarantee on Lumo AI Plus, and you can downgrade or cancel at any time without cancellation fees. Drop back to Free and your saved chats stay; the Plus limits end with your current billing period.
For comparison, ChatGPT Go costs €8 a month. OpenAI may train on chats from its personal plans, Go included, unless you opt out via privacy.openai.com ("do not train on my content") or use a Temporary Chat.
Buying for a team? Proton sells Lumo for Business separately, through Lumo Professional or as part of Proton Workspace. We have not listed those prices here.