Which to choose
| Use case | Pick | Why |
|---|---|---|
| Everyday chat, writing and file analysis | ChatGPT | Plus is USD 20 a month with reasoning models, deep research and 512MB file uploads |
| Work or client data in a managed workspace | ChatGPT | Business, Enterprise and Edu data is not used for training by default |
| Self-hosting a model on your own hardware | DeepSeek | V4.1 Flash weights are published on Hugging Face under the MIT License |
| Cheapest API calls for simple, high-volume tasks | ChatGPT | GPT-6 Luna lists USD 0.10 input and USD 0.50 output per 1M tokens, below DeepSeek's peak and off-peak Flash rates |
| Long generated outputs through an API | DeepSeek | Both DeepSeek models allow up to 384K output tokens, against 128,000 on GPT-6.1 Sol |
| Mid-tier reasoning API on a budget | DeepSeek | V4.1 Flash output costs USD 1.20 per 1M tokens at peak, against USD 10 for GPT-6.1 Sol |
Side by side
| Field | ChatGPT | DeepSeek |
|---|---|---|
| Free plan | Yes; unlimited everyday text chats with GPT-6, limited uploads, images and deep research | Web chat and mobile app linked from deepseek.com; no consumer price list published |
| Paid consumer plans | Go, Plus USD 20 a month, Pro USD 100 or 200 a month (new Pro 200 sign-ups paused since 10 September 2026) | None listed |
| API prices, entry model | GPT-6 Luna: USD 0.10 input, USD 0.50 output per 1M tokens | V4.1 Flash: USD 0.30 input (cache miss), USD 1.20 output per 1M tokens at peak; half off-peak |
| API prices, larger model | GPT-6.1 Sol: USD 2 input, USD 10 output | V4 Pro: USD 1.32 input, USD 3.96 output at peak |
| Context and output | 1,050,000 token API context; app reasoning context 256K on Plus, 400K on Pro | 1M token context; up to 384K output |
| File limits | 512MB per file, 80 files every 3 hours; Free users 3 uploads a day | |
| Platforms | Web, iOS, Android, desktop | Web, mobile app, Harness desktop app, API |
| Training default (consumer) | Used for training unless you opt out | Used for training unless you opt out |
| Team plan | Business and Enterprise | No team plan listed |
| Open weights | No | Yes, V4.1 Flash (MIT License) |
Prices as listed on 17 October 2026 on ChatGPT's pricing page, the ChatGPT Pro tiers article and DeepSeek's Models and Pricing page. All prices are in USD.
DeepSeek vs ChatGPT on API price
DeepSeek has a reputation as the cheap option, and against OpenAI's mid-tier model it is. DeepSeek V4.1 Flash, called as deepseek-flash, lists USD 0.30 per 1M cache-miss input tokens and USD 1.20 per 1M output tokens at peak. GPT-6.1 Sol lists USD 2 and USD 10, so Flash output costs about one eighth as much.
The picture flips at the bottom of OpenAI's range. The GPT-6 Luna model page lists USD 0.10 input and USD 0.50 output, which undercuts Flash even at DeepSeek's off-peak rates of USD 0.15 and USD 0.60. For classification, extraction and routing, Luna is the lower list price. Our GPT-6 Luna profile and DeepSeek V4.1 Flash profile carry the full rate cards.
Two billing rules shape real costs. DeepSeek's peak hours are 01:00 to 04:00 and 06:00 to 10:00 UTC on weekdays, and every other hour, including weekends, is half price. OpenAI's Sol page says Batch and Flex prices are 50% lower than Standard, and prompts above 272K input tokens bill at 2x input. DeepSeek also launched Search and Fetch APIs at USD 0.75 per 1,000 successful requests, with billing for calls made through its agent integrations starting on 1 November 2026.
DeepSeek's pricing page listed V4.1 Flash output at USD 1.20 per 1M tokens at peak on 17 October 2026, against USD 0.50 for OpenAI's GPT-6 Luna.
Open weights and self-hosting
This is the clearest difference. DeepSeek publishes the DeepSeek-V4.1-Flash model card and weights on Hugging Face under the MIT License. The card describes a multimodal mixture-of-experts model with 552B backbone parameters and support for contexts of up to one million tokens. OpenAI does not publish weights for its GPT-6 models; you reach them only through ChatGPT or the API.
Self-hosting changes the privacy question. If you run the weights on your own servers, prompts never reach DeepSeek's service, so its China storage clause does not apply to that traffic. The tradeoff is hardware: DeepSeek's V4.1 Flash announcement invites large deployments from teams with around 2,000 GPUs and a storage cluster. For most small teams, self-hosting a model this size is a project, not a setting. Our guide to open-weight and closed models covers the tradeoffs.
DeepSeek's Hugging Face model card listed V4.1 Flash under the MIT License with 552B backbone parameters on 17 October 2026.
The finished app
ChatGPT is a full product line. The pricing page lists Free, Go, Plus and Pro for individuals, with Business and Enterprise above them. Free includes unlimited everyday text chats with GPT-6, limited uploads, limited image creation and limited deep research. Plus adds advanced reasoning models, projects, scheduled tasks, custom GPTs and expanded Codex use, and the Plus help article lists it at USD 20 a month, billed monthly. Pro comes in USD 100 and USD 200 tiers, and new sign-ups to the USD 200 tier have been paused since 10 September 2026.
The ChatGPT file uploads FAQ sets a 512MB limit per file and 80 files every 3 hours, with Free users capped at 3 uploads a day. App context windows also step up by plan: the instant model has 27K tokens on Free and 54K on Plus, and reasoning models have 256K on Plus and 400K on Pro.
DeepSeek's consumer side is thinner on paper. Its homepage links a web chat, a mobile app and a desktop product called DeepSeek Harness, but the pages we read publish no consumer plans, usage caps or file limits. If you need to know what you are paying for and what the limits are, ChatGPT documents far more.
OpenAI's Plus help article listed ChatGPT Plus at USD 20 a month, billed monthly with no annual option, on 17 October 2026.
Model versions can change under you
Both vendors point a fixed name at a changing model. DeepSeek's pricing page says the legacy names deepseek-v4-flash and deepseek-v4-flash-vision-exp are retired and now served by DeepSeek-V4.1-Flash-1017. DeepSeek's 10 September 2026 announcement also said deepseek-v4-pro requests would be routed to V4.1 Flash after 14 September until a V4.1 Pro launches, while the pricing page on 17 October still lists V4 Pro (DeepSeek-V4-Pro-0813) with its own prices. Log the model version returned with each response and rerun your tests when it changes.
OpenAI's plan pages list several model generations side by side, and the Plus help article tells users to check the model picker for current access. In both cases, a test result is tied to a date.
DeepSeek's pricing page on 17 October 2026 said deepseek-flash is served by DeepSeek-V4.1-Flash-1017.
Data and privacy
ChatGPT. OpenAI's article on how your data is used to improve model performance says content from Free, Plus and Pro may be used for training. You can opt out by turning off "Improve the model for everyone" under Settings, Data controls. Thumbs up or down feedback can still make that conversation eligible. Temporary chats are not used for training while they stay temporary. By default OpenAI does not train on ChatGPT Business, Enterprise, Edu or API data.
DeepSeek. The DeepSeek privacy policy, last updated 10 February 2026, names Hangzhou DeepSeek Artificial Intelligence Co., Ltd. as the data controller. It says DeepSeek uses inputs, including prompts, uploaded files and chat history, to train and improve its models. It states: "we directly collect, process and store your Personal Data in People's Republic of China." The DeepSeek Terms of Use say you can opt out of training by turning off "Improve the model for everyone", and that disputes fall under the law of mainland China. The policy also tells users not to submit sensitive personal data.
Before you paste client, student or health data into either service, run through our AI tool privacy checklist.
If your rules restrict where data is processed, read DeepSeek's storage clause before the first prompt; self-hosting the open weights is the way around it.
How we compared them
On 17 October 2026 we read ChatGPT's pricing and Go plan pages, OpenAI Help Center articles on Plus, Pro tiers, file uploads and data use, and the GPT-6.1 Sol and GPT-6 Luna API model pages. For DeepSeek we read the Models and Pricing page, the API quick start, the V4.1 Flash announcement, the Hugging Face model card, the privacy policy and the terms of use. We compared documented plans, list prices, context and output limits, file limits, licensing and data terms, then made editorial picks per use case. Model facts match our DeepSeek provider profile and OpenAI provider profile, except where noted in the versions section. See how we rank for the method.
Frequently asked questions
Is DeepSeek cheaper than ChatGPT? It depends on the model you compare. DeepSeek V4.1 Flash output costs USD 1.20 per 1M tokens at peak, far below GPT-6.1 Sol's USD 10, but OpenAI's GPT-6 Luna lists USD 0.50, below Flash at any hour.
Is DeepSeek free to use? DeepSeek links a web chat and mobile app from its homepage and publishes no consumer subscription prices. Its API is pay as you go from a prepaid balance.
Where does DeepSeek store my data? In China, according to its privacy policy, which says it collects, processes and stores personal data in the People's Republic of China.
Can I stop DeepSeek training on my chats? Yes. DeepSeek's terms say you can opt out by turning off "Improve the model for everyone" in settings.
Can I run DeepSeek locally? Yes, if you have the hardware. DeepSeek publishes the V4.1 Flash weights on Hugging Face under the MIT License, and the model has 552B backbone parameters.
Which has the longer context window? They are close. DeepSeek lists 1M tokens for both API models, and OpenAI lists 1,050,000 tokens for its GPT-6 API models. In the ChatGPT app, reasoning context is 256K on Plus and 400K on Pro.
Which allows longer outputs? DeepSeek. Both of its API models allow up to 384K output tokens, while GPT-6.1 Sol lists 128,000.
Does DeepSeek have a business plan? No team or enterprise plan appears on the DeepSeek pages we read. ChatGPT offers Business and Enterprise plans with no training on workspace data by default.
Is the DeepSeek API cheaper at night? Off-peak hours cost half. Peak is 01:00 to 04:00 and 06:00 to 10:00 UTC, Monday to Friday, and weekends are off-peak all day.
Which is better for coding agents? For an API-driven agent on a budget, DeepSeek V4.1 Flash is the one to test first against GPT-6.1 Sol. For a packaged coding tool, see our sibling comparison of Cursor and Claude Code.