DeepSeek vs ChatGPT: Free Open Model or the Full-Featured Assistant?
ChatGPT is the better assistant; DeepSeek is the better bargain. ChatGPT has smarter top models (GPT-6 Astra and Sol), far more features (images, voice with video, deep research, Codex, ChatGPT Work) and stronger privacy controls.
DeepSeek is completely free, gives every user a 1-million-token context window and its V4 models are open-weight under the MIT licence. Its API is among the cheapest anywhere. But it stores data in China, censors politically sensitive topics and is banned on government devices in several countries. Use DeepSeek for maths, code and long documents that are not confidential; use ChatGPT for everything else.
At a glance
| ChatGPT | DeepSeek | |
|---|---|---|
| Price | Free; Go $8, Plus $20, Pro from $100/month | Free app, no paid plan; API paid per token |
| Top model (Sept 2026) | GPT-6 Astra (Pro), GPT-6 Sol and Luna | DeepSeek-V4-Pro (Expert mode), V4.1-Flash (Instant mode) |
| Artificial Analysis Intelligence Index | GPT-6 Astra 53, GPT-6 Sol 48, GPT-6 Luna 37 | V4.1 Flash 39, V4 Pro 36 |
| Context window in the app | 27K (Free) to 400K tokens (Pro reasoning) | 1M tokens |
| Image generation | Yes, on all plans | No |
| Open weights | No (separate gpt-oss models only) | Yes, MIT licence |
| Cheapest API price per 1M tokens | GPT-6 Sol: $2 in / $10 out | V4.1-Flash: $0.30 in / $1.20 out peak, half off-peak |
| Data storage | US-based company; training opt-out in Data Controls | Servers in the People's Republic of China |
Head to head
Price for chat users Winner: DeepSeek
DeepSeek's web and mobile apps are free with no paid tier at all, and you get the full V4-Pro model in Expert mode. ChatGPT Free is also generous since August 2026 (unlimited GPT-5.6 Luna text chats), but its best models sit behind Plus at $20 and Pro from $100, and free US users see ads.
Raw intelligence Winner: ChatGPT
On the Artificial Analysis Intelligence Index (a combined score across tough reasoning, science, maths and coding tests), GPT-6 Astra scores 53 and GPT-6 Sol 48, against 39 for DeepSeek V4.1 Flash and 36 for V4-Pro, as of 23 September 2026. Even OpenAI's cheap GPT-6 Luna (37) is level with DeepSeek's best. The gap is clear on hard problems, less so on everyday questions.
Long documents Winner: DeepSeek
Both DeepSeek V4 models have a 1-million-token context window, and the free app uses it. ChatGPT Free is limited to 27K tokens for Instant chats; Plus reaches 256K and Pro 400K for reasoning. If you want to paste a whole book or a large codebase for free, DeepSeek holds far more.
Features Winner: ChatGPT
ChatGPT offers web search, deep research, image creation, voice with video, memory, projects, scheduled tasks, custom GPTs, ChatGPT Work and the Codex coding agent. DeepSeek offers chat with Instant and Expert modes, a thinking toggle, web search, file uploads and image understanding (added with V4.1-Flash on 10 September 2026). It cannot create images.
Coding Winner: ChatGPT
DeepSeek says V4-Pro is the best open model on agentic coding tests, and it is a strong, cheap choice for code questions. ChatGPT still wins for most coders: GPT-6 models score higher on independent indexes, and Codex can edit files, run tests and work in the background from the same subscription.
API price Winner: DeepSeek
DeepSeek V4.1-Flash costs $0.30 per million input tokens and $1.20 per million output tokens at peak, and half that off-peak (peak is 01:00–04:00 and 06:00–10:00 UTC on weekdays). V4-Pro costs $1.32 / $3.96 at peak. OpenAI's GPT-6 Sol costs $2 / $10 and GPT-6 Astra $10 / $50. For bulk tasks, DeepSeek is several times cheaper.
Open weights and self-hosting Winner: DeepSeek
DeepSeek releases its V4 model weights under the permissive MIT licence, so companies can run them on their own servers and keep data in-house. V4-Pro has 1.6 trillion total parameters (49 billion active), so it needs serious hardware; V4-Flash is 284 billion total (13 billion active). ChatGPT's GPT-6 models are closed; OpenAI's open-weight option is the older gpt-oss.
Privacy and security Winner: ChatGPT
DeepSeek's privacy policy says data is stored in China. Italy, South Korea, Australia, Canada, Taiwan, Texas, the US Commerce Department and the Czech Republic have restricted it on official devices, and South Korea's regulator found it sent user data abroad without consent. ChatGPT lets you turn off model training in Data Controls and offers Temporary Chats; Business and Enterprise data is not used for training by default.
Honest answers on sensitive topics Winner: ChatGPT
The DeepSeek app refuses or deletes answers on topics such as Tiananmen Square, Taiwan's status and criticism of Xi Jinping. The open weights can be run without that app-level filter, but the official app applies it. ChatGPT has its own safety refusals but no state-directed topic bans.
Which should you choose?
Choose ChatGPT if…
- You want one app for chat, images, voice, research and coding
- You handle work, personal or confidential information
- You need the strongest reasoning models (GPT-6 Astra on Pro)
- You want features like memory, projects and scheduled tasks
Choose DeepSeek if…
- You want a strong model completely free, with no ads
- You need to paste very long, non-sensitive documents (1M-token context)
- You are a developer who wants the cheapest capable API or open weights to self-host
- You mostly do maths, coding practice or step-by-step problem solving
ChatGPT wins six of nine rounds and is the better daily assistant. Its GPT-6 models score clearly higher on independent tests, and it does far more: images, voice, deep research, Codex and ChatGPT Work.
DeepSeek wins on money and openness. The app is free with a 1-million-token context, the API is several times cheaper than OpenAI's, and the MIT-licensed weights let companies run the model privately.
Pick ChatGPT if you want the most capable, polished assistant and care about where your data goes. Pick DeepSeek if you want free, strong reasoning for homework, code or long public documents, or a low-cost API.
Do not use the DeepSeek app for confidential work, anything covered by your employer's security policy, or questions about Chinese politics. If you like DeepSeek's models but not its app, run the open weights through a Western cloud provider instead.
The models behind each app
| ChatGPT | DeepSeek | |
|---|---|---|
| Fast model | GPT-5.6 Luna (Free/Go chat) | V4.1-Flash (Instant mode) |
| Strong model | GPT-6 reasoning, GPT-6 Sol (Plus) | V4-Pro (Expert mode) |
| Top model | GPT-6 Astra Pro reasoning (Pro) | V4-Pro with max thinking |
| Context | 27K–400K depending on plan | 1M tokens |
DeepSeek released V4 on 24 April 2026. V4-Pro became generally available on 13 August 2026 with three thinking levels (low, high, max), and V4.1-Flash replaced V4-Flash on 10 September 2026. OpenAI released GPT-6 Astra on 3–4 September and GPT-6 Sol and Luna on 22 September 2026.
Benchmarks: how far apart are they?
Artificial Analysis Intelligence Index, best setting for each model, as of 23 September 2026:
| Model | Score |
|---|---|
| GPT-6 Astra (max) | 53 |
| GPT-6 Sol (max) | 48 |
| DeepSeek V4.1 Flash (max) | 39 |
| GPT-6 Luna (max) | 37 |
| DeepSeek V4 Pro 0813 (max) | 36 |
The index combines many hard tests into one number. A 14-point gap between Astra and DeepSeek's best is large on difficult tasks. For short everyday questions most users will not notice it. Note that the cheaper V4.1-Flash scores above the older V4-Pro.
API pricing compared
| Model | Input / 1M tokens | Output / 1M tokens |
|---|---|---|
| DeepSeek V4.1-Flash (peak) | $0.30 | $1.20 |
| DeepSeek V4-Pro (peak) | $1.32 | $3.96 |
| OpenAI GPT-6 Sol | $2.00 | $10.00 |
| OpenAI GPT-6 Astra | $10.00 | $50.00 |
DeepSeek charges half these rates off-peak, including all weekend. Cached input (text the API has already seen) is far cheaper on both platforms. Prices from each vendor's pricing page, 23 September 2026.
Privacy: the deciding factor for many users
DeepSeek is run by a Hangzhou-based company, and its privacy policy says it stores personal data on servers in China. Several governments restrict it on official devices, and Italy's data regulator blocked the app in January 2025. A database leak in January 2025 exposed chat histories and API keys.
ChatGPT is not private by default either: consumer chats can be used for training unless you switch that off. But it gives you the controls, and it is subject to US and EU data law rather than Chinese law.
- Use DeepSeek's Expert mode for maths and logic problems, and Instant mode for quick lookups. Expert mode is slower but thinks longer.
- Strip names, addresses and company details from anything you paste into DeepSeek. Treat it like a public forum.
- If you like DeepSeek's quality but need privacy, call the open V4 weights through a US or EU cloud host instead of the official app.
- Developers: schedule DeepSeek batch jobs outside 01:00–04:00 and 06:00–10:00 UTC on weekdays to pay the half-price off-peak rate.
- For long documents on ChatGPT Free, split them into parts; its 27K-token Instant context is far smaller than DeepSeek's 1M.
Jargon explained
- Open weights
- The trained model files are published, so anyone can download and run the model on their own computers.
- MIT licence
- A very permissive software licence. It lets you use, change and sell the model with almost no restrictions.
- Context window
- How much text a model can read at once, measured in tokens. One million tokens is roughly 750,000 words.
- Active parameters
- The part of a large model that actually works on each word. Fewer active parameters make a big model faster and cheaper to run.
- Artificial Analysis Intelligence Index
- An independent score that combines results from many hard AI tests into one number, so models can be compared.
Frequently asked questions
Is DeepSeek better than ChatGPT?
Not overall. ChatGPT's GPT-6 models score higher on the Artificial Analysis Intelligence Index (53 for Astra versus 39 for DeepSeek's best) and ChatGPT has far more features. DeepSeek is better on price, context length and openness.
Is DeepSeek free?
Yes. The web and mobile apps have no paid plan. Only the developer API costs money, from $0.15 per million input tokens off-peak for V4.1-Flash.
Is DeepSeek safe to use?
It is safe for public, non-sensitive tasks like maths or coding practice. Avoid it for confidential data: it stores data in China and is banned on government devices in several countries.
Can I run DeepSeek offline?
Yes, in principle. The V4 weights are released under the MIT licence. But V4-Pro has 1.6 trillion parameters, so running it needs a multi-GPU server. Most people use smaller open models for local use; see our best local LLMs ranking.
Does DeepSeek make images?
No. It can understand images you upload (since V4.1-Flash), but it cannot create them. ChatGPT can create images on every plan.
Sources
Every fact on this page comes from public information. Vendor figures are labelled as vendor claims.
- DeepSeek API change log (DeepSeek)
- Models and pricing (DeepSeek)
- DeepSeek V4 Preview Release (DeepSeek)
- DeepSeek adds instant and expert chatbot modes (South China Morning Post)
- DeepSeek (chatbot) (Wikipedia)
- DeepSeek privacy policy (DeepSeek)
- LLM leaderboard (Artificial Analysis)
- ChatGPT pricing (OpenAI)
- Introducing GPT-6 Sol and Luna (OpenAI)