The short answer
Value, openness, visible reasoning
You want strong results for free or at very low API cost, like seeing the model's full reasoning, want open-weight models you can run yourself, or want an open-source desktop agent (Harness).
Ecosystem and polish
You rely on a broad set of built-in features and integrations, such as image generation, advanced voice, custom assistants and connections to many third-party apps, and prefer one polished product.
DeepSeek vs ChatGPT at a glance
| DeepSeek | ChatGPT | |
|---|---|---|
| Made by | DeepSeek (China) | OpenAI (USA) |
| Free chat | ✓ Generous, including reasoning mode and web search | ✓ With usage limits. Top models and higher limits are on paid plans |
| Open-weight models | ✓ Most models published to download and self-host | ◐ Some open-weight releases. The flagship ChatGPT models are closed |
| Visible reasoning | ✓ The full chain of thought from R1 / DeepThink | ◐ Shows a summary of its reasoning |
| API price | Among the lowest per token | Generally higher for comparable models |
| API compatibility | OpenAI-compatible format | The original format |
| Ecosystem | Growing: apps, API, Harness, plugins, open-source community | Very broad: custom assistants, many integrations, image and voice features |
| Desktop agent | Harness Desktop: open source, works on your files | Its own desktop and agent features (check OpenAI for details) |
| Data hosting | Hosted by DeepSeek, or self-host the open weights | Hosted by OpenAI. Business plans add data controls |
Feature by feature
| Feature | DeepSeek | ChatGPT |
|---|---|---|
| Everyday chat - writing | Strong. V4.1 Flash is fast by default, with V4 Pro for the hardest tasks | Strong, with a polished, conversational style |
| Reasoning (maths, logic) | R1 via DeepThink, with its reasoning fully visible | Reasoning models, with summarised thinking |
| Web search | ✓ Search toggle in chat; search - fetch in the API | ✓ Built-in web search |
| File - image upload | ✓ PDFs, documents, spreadsheets, images | ✓ Broad file and image support |
| Image generation | - | ✓ Built in |
| Voice | Voice input in the mobile app | ✓ Advanced two-way voice conversation |
| Coding | Very strong: Coder, R1 and Harness Coding | Very strong, with its own coding agents and IDE integrations |
| Agents - automation | Harness: documents, spreadsheets, scheduled tasks, plugins | Its own agent, task and app-integration features |
| Custom assistants | Via system prompts in the API, or Harness plugins | ✓ Custom assistants you can build and share in the app |
| Self-hosting | ✓ Open weights, including small distilled versions | Limited to its open-weight releases |
| Languages | Dozens, and especially strong in English and Chinese | Dozens, with broad coverage |
Best choice by use case
| If you mainly want to… | Lean towards | Why |
|---|---|---|
| Get strong answers for free | DeepSeek | A generous free tier, including reasoning and search. |
| Solve maths or logic and see the working | DeepSeek | R1 shows its full chain of thought. |
| Build an app at low cost | DeepSeek | Low per-token API prices and an OpenAI-compatible format. See API guide. |
| Keep data fully in-house | DeepSeek (self-hosted) | Open weights run on your own hardware. |
| Generate images | ChatGPT | Image generation is built in. |
| Have natural voice conversations | ChatGPT | More advanced two-way voice. |
| Connect to many work apps out of the box | ChatGPT | A larger ecosystem of integrations and custom assistants. |
| Code with an AI agent | Either | Both are strong. DeepSeek's Harness is open source and low-cost. |
| Write, summarise, translate | Either | Both are excellent, so pick on price, style or habit. |
Cost: free tiers and the API
For everyday users
Both have a free tier. DeepSeek's free chat includes its reasoning mode and web search. ChatGPT's free tier has usage limits, and its best models and higher limits are on paid plans.
For developers
DeepSeek's API is among the cheapest per token, and the V4.1-Flash-1017 update lowered its cost per task further. Because the request format is OpenAI-compatible, switching often means changing just the base URL, key and model name.
Privacy and data: what to consider
This is often the deciding factor for businesses, so here are the facts, plainly:
| Topic | DeepSeek | ChatGPT |
|---|---|---|
| Where hosted data is processed | DeepSeek's services are run by a company based in China. Its privacy policy describes where data is stored, so read it before sharing sensitive information. | OpenAI is based in the USA. Its privacy policy and business terms describe data use and storage. |
| Use for training | Check DeepSeek's current privacy policy and settings. | Consumer and business plans differ. Check OpenAI's settings and terms. |
| Full control option | Self-host the open weights, so no data leaves your network. See open weights. | Business and enterprise plans add data controls. Most models can't be self-hosted. |
| Workplace rules | Some organisations and public bodies restrict DeepSeek's hosted app on work devices. | Some organisations restrict or require approved versions of ChatGPT too. |
Pros and cons
Pros
- Generous free chat with reasoning and search
- Very low API cost
- Open weights you can self-host and fine-tune
- Full, readable reasoning from R1
- Open-source desktop agent (Harness)
Cons
- Smaller ecosystem of integrations
- No built-in image generation
- "Server busy" at peak times
- Data-hosting concerns for some organisations
Pros
- Very polished, all-in-one app
- Image generation and advanced voice
- Huge ecosystem: custom assistants, many integrations
- Mature business and enterprise options
Cons
- Best features and limits need a paid plan
- Higher API costs for comparable models
- Flagship models can't be self-hosted
- Reasoning shown only as a summary
Which is right for me? Answer three questions
1. What matters most?
2. Will you build something with the API?
3. Do you want to see how the AI reasons?
Your suggestion will appear here.
Switching from ChatGPT, or using both
| If you… | Do this |
|---|---|
| Use ChatGPT for chat | Try the same prompts in DeepSeek chat or the mobile app. Your prompts work as they are. Our how-to guide covers DeepThink and Search. |
| Use OpenAI's API | Point your existing OpenAI SDK at https://api.deepseek.com with a DeepSeek key and model name. Most chat code runs unchanged. See the API guide. |
| Want the best of both | Send everyday and high-volume work to DeepSeek, and keep ChatGPT for images, voice or integrations it alone has. |
| Can't sign in to DeepSeek | See the login guide. Peak-time "server busy" messages are covered there too. |
Compare them yourself
- Pick 5 to 10 real tasks you actually do: an email, a summary, a coding question, a research question, a tricky reasoning problem.
- Use the same wording in both, and turn on the equivalent features: DeepThink in DeepSeek, reasoning in ChatGPT, and web search in both where needed.
- Hide which is which and score each answer for accuracy, usefulness and style.
- Note speed and limits: which made you wait, and which hit a usage cap.
- Decide per task. You may find each wins different jobs.
DeepSeek vs ChatGPT - frequently asked questions
Is DeepSeek better than ChatGPT?
Neither is better at everything. DeepSeek leads on cost, openness and visible reasoning. ChatGPT leads on ecosystem, image generation and voice. For everyday writing and questions they're close.
Is DeepSeek free like ChatGPT?
Yes. Both have free chat. DeepSeek's free tier includes reasoning and web search, while ChatGPT puts its best models and higher limits on paid plans.
Which is cheaper for developers?
DeepSeek's API is generally much cheaper per token. See DeepSeek API pricing, and compare with OpenAI's official prices.
Can I use my OpenAI code with DeepSeek?
Usually yes. The DeepSeek API is OpenAI-compatible, so change the base URL, key and model name.
Is DeepSeek safe to use?
The official apps are safe to install from official stores. As with any hosted AI, avoid sharing sensitive data, and read DeepSeek's privacy policy. Organisations with strict requirements can self-host the open-weight models.
Which is better for coding?
Both are excellent. DeepSeek offers Coder, R1 for hard bugs, and the open-source Harness Coding agent at low cost.
Is this comparison sponsored?
No. DeepSeekR1.com is independent and isn't affiliated with DeepSeek or OpenAI. See about us, our disclaimer, privacy policy and terms.