Both can be used without paying — which makes this a comparison of what free actually buys. Copilot's free tier is a taste of an Office product; DeepSeek's free tier is the whole frontier-class product.
DeepSeek is the stronger free AI — frontier reasoning, unlimited, $0. Copilot wins only where integration is the product: inside Word, Excel and Outlook, paired with an Office subscription ($16.67/mo M365 Premium).
By Microsoft. Full Copilot profile →
By DeepSeek AI. Full DeepSeek profile →
Best for: Excel data, Word drafting, PowerPoint decks, Outlook triage
Weakness: Pro plan is half-useful without an M365 subscription on top
From $0 (free)/mo. Top tier: $16.67/mo.
Best for: Math, logic, coding for users on a budget — or curious experimenters
Weakness: Hosted in China; data residency may matter; less polished UX
From $0 (free)/mo. Top tier: $—/mo.
Pick Copilot if Office integration is the point — no free AI drafts inside Word or builds Excel formulas in place. The M365 Premium bundle ($16.67/mo) makes sense if you'd buy Office anyway.
Pick DeepSeek for the strongest no-cost intelligence: unlimited frontier-class reasoning and coding with no paywall, no caps that matter, no bundle required.
In-Office work → Copilot. Everything a chat window can do → DeepSeek does it free, and mostly better.
As a raw assistant, yes — DeepSeek V4's reasoning outclasses Copilot's consumer tier, and it's unlimited and free. Copilot's value is placement inside Office, not model strength.
Basic chat is free in Windows and Edge. The Office-integrated features require Microsoft 365 Premium ($16.67/mo, billed $199.99/year).
Integration and multimodal extras: no Office hooks, no image generation in apps, fewer enterprise controls — and it's operated from China, which matters for some workplaces.