DeepSeek is a sensible free assistant for questions, writing and coding help. ChatGPT is our recommendation if creating images or organizing ongoing work in Projects matters to you. For research and finished documents, compare ChatGPT Work with DeepSeek Harness: the right choice depends on your source material, required output and access costs.
Start with the free versions. ChatGPT is not a paid-only alternative to DeepSeek, and a subscription is worth considering only when a useful feature or a recurring limit changes what you can get done. The differences below explain where that happens, including the separate costs of agent tools and APIs.
| What you need | Where to start | Why |
|---|---|---|
| Everyday answers, a draft or an explanation | Either free assistant | Choose the answer that follows your brief and needs less correction. |
| Related chats with recurring files and instructions | ChatGPT Projects | Keep the material for a client, course or ongoing assignment together. |
| A current fact with a supporting source | Search in either assistant | Both can find web material; check the source behind the answer. |
| A report drawing on several sources, followed by an editable file | ChatGPT Work; consider DeepSeek Harness for desktop work | These are task-oriented tools beyond an ordinary chat. Access and billing differ. |
| Creating or editing a picture | ChatGPT | A documented image-generation and editing workflow, with plan-specific limits. |
| Running model inference on your own computer | A downloadable DeepSeek model | You control the setup, but need suitable hardware and separate software. |
Jump to free and paid access, writing, research, documents, images and voice, coding or privacy.
Free access and when paying makes sense
The official DeepSeek mobile assistant is advertised as free. Its app listing describes search, file uploads and image understanding, alongside chat. Free access should not be read as a guarantee of unlimited capacity or identical availability everywhere.
ChatGPT Free includes web search, file and image uploads, data analysis and image creation. Those tools have usage limits, and reaching a file or image limit does not necessarily mean ordinary conversation has stopped. Plus offers higher limits. That makes the free plan a reasonable starting point for occasional document questions or images, rather than something you must upgrade before trying.
As checked on October 4, 2026, OpenAI lists Go at $8 per month and Plus at $20 per month, with higher Pro options. These are published USD prices; check the price and included features shown for your account before subscribing. Plus is one paid option, not the entry price of ChatGPT.
A useful upgrade decision starts with a specific interruption. If you repeatedly exhaust the uploads you need for daily work, a higher allowance may be worth paying for. If you only ask a few questions or revise occasional emails, the free service may already be enough. Paying for a larger plan does not remove the need to check the answers.
DeepSeek Harness has different billing from the free assistant. Its terms require a DeepSeek account and prepaid Open Platform funds for the default official-model service. With a custom model provider, that provider’s charges apply. A free client download or public preview does not mean the model usage is free.
For developers, consumer chat access and API spending are separate. OpenAI bills API usage separately from ChatGPT subscription usage, and DeepSeek’s free assistant does not make its API free. Our DeepSeek pricing guide explains that billing separately. Token prices are useful for an application budget; they are not the monthly price of an equivalent chat subscription.
Writing, learning and everyday questions
For an email, a study explanation or a first draft, neither a feature checklist nor an old model score tells you which answer you will prefer. The important question is whether the assistant follows the brief without introducing facts you did not supply.
For example, ask for an email explaining a delivery delay. Give the actual reason, the revised date and the tone you want. A useful response preserves those facts, avoids inventing compensation and gives the recipient a clear next step. Choose the version that needs less factual and stylistic repair, rather than the one that sounds most elaborate.
The same principle applies to learning. Ask the assistant to explain the step you do not understand, then work through a similar example yourself. A worked solution helps only if you can follow the reasoning. For an unfamiliar factual topic, ask for sources instead of treating a confident explanation as evidence.
ChatGPT has a practical advantage for recurring work through Projects, which collect related chats, sources and instructions. You can keep a client brief and writing preferences together across conversations. Projects are not simply a paid-only concept: OpenAI’s file guide lists allowances for Free as well as paid projects. The capacity differs by plan.
If you rarely return to the same material, that organization may not change your choice. If you repeatedly paste the same instructions and files, it can matter more than a small preference for one assistant’s default writing style.
Research: a quick lookup or a sourced report?
Both assistants can search the web. DeepSeek’s terms describe its Search feature, and OpenAI documents web search with sources. For a focused question, such as whether a product supports a particular file format, either is a reasonable place to begin. Ask for the current official documentation and open the relevant page.
A question about an uploaded document is a different job. If you have a proposal, ask, “Which services are excluded, and which passages establish that?” The answer should point back to your file. A general web answer about typical contracts would not resolve the question, even if it were well written.
For a larger investigation, ChatGPT’s Deep research in Work is designed to investigate multiple sources and produce a report. OpenAI describes a Deep research plugin on desktop and a Deep research option in the web interface’s + menu, where available. Access depends on the account and workspace settings; ordinary free web search is not a promise of unlimited Deep research.
Suppose you want to compare two software products using their current terms, your team’s requirements and several uploaded proposals. Give the research task a clear scope: the same region, the relevant plans, the date of the documents and the decisions you need to make. Ask it to separate confirmed facts, differences and unanswered questions. This is a better fit for a research workflow than a single broad prompt asking which product is best.
DeepSeek also has a separate research route in Harness, which advertises source research alongside document and data tasks. Consider it when you want a desktop agent to work across local material, with the billing distinction explained above. The free assistant and Harness are different products, so the presence of Search in one does not establish every capability of the other.
Whichever route you use, check the claims that determine your decision. A citation should support the actual conclusion, not merely discuss the same topic. Also check that the cited price, limitation or feature applies to the same plan and date. A report can include real sources and still draw the wrong conclusion from them.
Files and finished documents
Being able to read a file is not the same as producing a file you can use. For a few questions about a PDF, ordinary chat may be sufficient. For an editable spreadsheet, a presentation and a written summary from the same source material, look at the workflow for creating and revising those outputs.
ChatGPT Work can create documents, spreadsheets, presentations and PDFs from supplied material. You can review the result, request changes and download it. It is a useful starting point when the deliverable matters as much as the answer: for example, a spreadsheet with the underlying calculations rather than a table pasted into a chat.
Harness is another option for document, data and slide work, currently presented as a public preview. Its desktop setup is relevant when your task involves workspace files and tools. Choose between these workflows by the output you need and where your source files live; their feature descriptions alone do not establish which will produce the better result.
Make the request concrete: identify the input files, the output format, the calculations or sections required and anything that must stay unchanged. Before using the result, inspect formulas, units, totals and whether the presentation accurately reflects its source.
For scanned documents or charts inside a PDF, check that the relevant visual information was actually read. OpenAI’s upload documentation lists visual retrieval for PDFs on Enterprise; other plans, including Free and Plus, use text extraction for those document uploads. A chart embedded in a PDF can therefore be missed even when the assistant accepts separate images. Supply the relevant chart as an image when you need it inspected.
Images and voice
For creating a picture or changing an existing one, ChatGPT is our recommendation because it has a documented image-generation and editing workflow. Attach a reference, explain the change and say what should remain unchanged. ChatGPT’s consumer Free plan includes image creation with limits; access in Work or Codex can differ, so do not transfer one interface’s allowance to another.
Reading a picture is a separate task. Both ChatGPT and the current DeepSeek app support image understanding. For a screenshot or photographed diagram, explain what you want to know and check small labels or numbers in the response.
Voice needs the same attention to product scope. OpenAI’s desktop voice guide documents live conversations on Plus, Pro, Business, Edu and Enterprise, subject to availability. This is a specific desktop experience, not a complete list of voice options across every mobile and web account. If voice is your main reason to choose a service, check live conversation on your intended device; dictating a prompt is not the same thing.
Coding help versus working on a project
For a short function, an error message or an unfamiliar line of code, either chat is a reasonable place to begin. Include the relevant code, the expected behavior and what happened instead. A useful answer explains the cause and proposes a change you can check. Our DeepSeek coding guide develops that process further.
A repository-wide task requires more: reading the surrounding files, making compatible changes and running the project’s checks. Codex provides that development workflow, while Harness also advertises repository work, bug fixes and tests. This is a different comparison from asking each chat to write a function.
Cost and access can change the choice. OpenAI’s plan page lists limited desktop Codex access for Free and Go, subject to rollout, while Plus includes additional surfaces such as the CLI and IDE extension. Work and Codex share usage. Harness’s default model service draws on prepaid funds. Compare the route you will actually use rather than assuming either agent is covered by ordinary free chat.
For a real project, define the requested behavior and review the proposed changes before accepting them. Check whether the fix preserves existing functionality and whether the tests address the original problem. A claim that one model won a coding benchmark is not enough to establish that its assistant will safely handle your codebase.
Privacy on personal accounts, and the local option
For confidential work, the account and data arrangement may decide the choice before features do. A paid personal subscription is not automatically a business service with the same privacy commitments.
DeepSeek’s privacy policy covers prompts and uploads and says personal data is processed and stored in China. Its consumer terms describe the “Improve the model for everyone” opt-out. Turning it off addresses use for model improvement; it is separate from deleting conversations and does not promise that all retention ends.
For a personal ChatGPT account, go to Settings → Data controls → Improve the model for everyone. OpenAI says disabling it prevents new conversations from being used for training, while saved chats remain in history. Providing feedback on a response can allow the associated conversation to be used for training. These details are explained in its data controls guide.
ChatGPT’s Temporary Chat is a separate choice. While temporary, the chat does not appear in history, create or update memories, or train models; OpenAI says it may retain it for up to 30 days for safety. Saving it as a regular chat changes how the account’s settings apply. Temporary Chat therefore should not be described as a zero-retention mode.
OpenAI’s no-training-by-default commitment for Business, Enterprise and Edu workspaces is distinct from these personal-account controls. For client or company files, use the service and workspace your organization permits. Changing a personal training setting does not itself authorize uploading confidential material.
Harness also has its own privacy policy. When configured with a custom model provider, inputs and outputs go to that provider. Installing an agent locally does not make the model processing local, nor does the mobile assistant’s setting necessarily control that separate service.
If local inference is the priority, DeepSeek publishes downloadable model weights, including smaller models. You take on the hardware, setup and software choices; our system requirements guide explains that distinction. A smaller local model will not reproduce every capability of the hosted assistant. Check external connections too: a local chat interface can still call a remote API.
Frequently asked questions
Can DeepSeek replace ChatGPT Plus?
It can replace the parts you use for ordinary questions, drafts and conversational coding help if you are satisfied with the results and available capacity. Before canceling a subscription, identify the tools you actually rely on: image editing, recurring project context, research or a specific agent workflow. Free chat does not automatically replace that whole bundle. If those extras are not useful to you, paying merely to keep a second assistant is hard to justify.
Which is more accurate?
There is no universal accuracy winner established by this comparison. A fluent answer, a source link and a correct calculation are different things. Check the evidence for factual claims, the assumptions behind a recommendation and the behavior of generated code. Use the comparison to choose a suitable workflow, not to excuse either assistant from verification.
Is there a reason to use both?
Yes, when they serve different tasks. You might prefer DeepSeek for a quick explanation and ChatGPT for editing an image or organizing a continuing project. There is no need to move every task to one service, but avoid uploading the same sensitive material to multiple services simply to compare their answers.
If you decide to start with DeepSeek, our DeepSeek guide brings together the official access routes and the main ways to use it. Chat-Deep is an independent site, not either provider’s official service.