DeepSeek V3 doesn’t exist as an active product anymore. DeepSeek deprecated the V3.2 API endpoints on July 24, 2026, replacing the entire lineup with V4. And “ChatGPT” stopped meaning one thing back in July, when OpenAI split its free and paid tiers onto genuinely different models rather than the same model with a usage cap. If you’re comparing free AI options right now, the real question is DeepSeek V4 against GPT-5.6 Luna specifically, not the vague “ChatGPT” most search results are still using.
What the Old Comparison Gets Wrong
Search “DeepSeek V3 vs ChatGPT” today and you’ll find articles built around a model DeepSeek has already retired and a version of ChatGPT that predates the current free-tier split entirely. That’s not a small inaccuracy. DeepSeek V4 represents a real architectural jump, not an incremental patch, and OpenAI’s decision to give free users a genuinely distinct model rather than a rate-limited version of the flagship changes what “free ChatGPT” actually gets you in ways that make older comparisons actively misleading rather than just outdated.
What You’re Actually Comparing Right Now
DeepSeek V4 launched April 24, 2026, as two variants: V4 Pro, a 1.6 trillion parameter mixture-of-experts model with 49 billion active parameters per token, and V4 Flash, a lighter 284 billion parameter version built for speed and cost efficiency. Both support a 1 million token context window, a substantial jump from V3’s 128,000 token ceiling, achieved through a new hybrid attention architecture that keeps that much longer context computationally affordable.
GPT-5.6 Luna is the smallest model in OpenAI’s current GPT-5.6 family, and since August 2026 it’s the only model free ChatGPT accounts can actually use, with no picker and no fallback to anything larger. Paid subscribers get GPT-5.6 Sol, and Plus and Pro users have since gained access to GPT-6 Astra following its September 3 launch. Free accounts have neither.
How to Actually Access Each One for Free
DeepSeek
DeepSeek’s chat interface at chat.deepseek.com is free to use directly with no subscription tier at all, running the V4 family with no message cap comparable to what ChatGPT enforced before August. Because DeepSeek releases its models under an open license, V4 is also available to run locally or through third-party hosts if you have the hardware or budget for API access, at notably low published rates, $0.14 per million input tokens and $0.28 per million output tokens for V4 Flash, a fraction of what comparable Western models charge.
ChatGPT
Free ChatGPT access requires only an account, no payment method, and since the week of August 10, 2026, text conversations are unlimited rather than capped by message count. That unlimited access comes with real restrictions beyond just the model tier: free accounts get a single reasoning mode rather than the adjustable thinking depth paid tiers offer, and voice mode defaults to a smaller Live-1 mini model rather than Luna itself.
The Benchmark Comparison That Actually Applies Here
This is where most existing comparisons quietly go wrong. A lot of “ChatGPT vs DeepSeek” content online cites benchmark numbers for GPT-5.6 Sol or even GPT-6 Astra while writing as though those numbers describe the free experience. They don’t. Sol and Astra are paid-tier models. Luna is a smaller, faster model specifically built to serve OpenAI’s free tier at scale, and it has not been benchmarked as extensively or as publicly as its larger siblings, which makes a precise, sourced head-to-head against Luna specifically harder to state with confidence than most roundups let on.
What is well documented is DeepSeek V4’s own benchmark profile against the broader field. V4 posted meaningful gains over V3.2 across standard evaluations, and V3.2’s own predecessor scored 73.1 percent on SWE-Bench Verified with its research-focused Speciale variant hitting gold-medal-level results on international math and informatics olympiads. That puts DeepSeek’s flagship, freely accessible through its chat interface, competing at a tier most free products don’t reach at all. Until OpenAI or independent researchers publish clearer Luna-specific benchmark data rather than family-wide GPT-5.6 numbers, treat any specific score comparing Luna directly against V4 with real skepticism, including scores you find on other sites that don’t specify which GPT-5.6 tier they actually tested.
Where Each One Genuinely Has the Edge
DeepSeek V4’s biggest practical advantage for free use is the 1 million token context window, well beyond what most users will ever need in a single conversation but genuinely useful for anyone working with long documents, large codebases, or extended research threads without hitting a hard wall. Its open licensing is a second real advantage unrelated to raw capability, giving developers and privacy-conscious users the option to self-host rather than depend on a single company’s servers and terms of service.
ChatGPT’s free tier wins on interface polish and ecosystem breadth. Free accounts get image generation with its own separate daily cap, file uploads including PDFs and spreadsheets, a working Code Interpreter for running Python, and integration with OpenAI’s broader tool ecosystem including limited access to Codex and Work. DeepSeek’s chat interface is functional but considerably more bare-bones by comparison, without the multimodal file and image handling ChatGPT’s free tier includes by default.
The Question Nobody’s Free-Tier Answers Well
Neither free tier gives you the actual best model either company makes, and that gap matters more with DeepSeek V4 and GPT-5.6 Luna specifically than it used to. V4 Pro exists, at genuinely low API pricing, as a meaningfully more capable option than what most people will experience through DeepSeek’s default free chat routing. Luna sits multiple tiers below Sol and further still below Astra, OpenAI’s newly launched flagship. If your evaluation criteria is “best model I can get without paying anything,” DeepSeek’s fully open V4 family, accessible for free through its chat interface with no rate-limit-driven downgrade to a smaller model, currently makes a stronger case than ChatGPT’s free tier does, precisely because OpenAI’s free experience is deliberately built around its smallest model rather than a capped version of its best one.
The Privacy Question That Matters More With DeepSeek Specifically
Data handling is worth addressing directly rather than skipping, since it’s a genuinely different risk profile between these two options. DeepSeek is a Chinese company, and its terms of service specify that user data is stored on servers located in China, subject to Chinese data regulations rather than the frameworks that apply to U.S.-based services. That’s led several governments and corporate IT departments to restrict or ban DeepSeek’s hosted service on official devices, even in cases where the underlying model itself, being open-weight, could be run locally instead with no data leaving your own hardware.
OpenAI’s free tier stores conversation data on U.S. and partner infrastructure under its own published privacy policy, subject to a different regulatory environment. Neither company’s free tier should be treated as fully private by default, both retain conversations for model improvement unless you specifically opt out where that option exists, but the jurisdictional difference is worth knowing before you put anything sensitive into either tool’s free chat interface specifically, as opposed to a self-hosted or enterprise-tier deployment with different data terms.
Which One Actually Handles Coding Tasks Better for Free
Coding is one of the more common reasons people reach for either tool, and it’s worth addressing separately from general benchmark talk. DeepSeek’s models have built a specific reputation in the developer community for strong code generation and debugging relative to their size and cost, a big part of why DeepSeek gained traction with technical users well before V4 shipped. V4’s improvements over V3.2 extend that strength further, and DeepSeek’s chat interface gives free users direct access to that capability without a smaller, coding-weaker fallback model.
ChatGPT’s free tier includes a working Code Interpreter for running and testing Python directly in the browser, a genuinely useful feature DeepSeek’s interface doesn’t match, letting you execute code rather than just generate and manually verify it yourself. For pure code generation quality on a single free account with no execution environment, DeepSeek’s reputation and V4’s benchmark gains give it a real edge. For actually running and iterating on code without leaving the chat interface, ChatGPT free’s Code Interpreter is the more complete free tool, even running on Luna rather than a larger model.
How to Actually Decide Between Them
If long-context work, self-hosting flexibility, or extremely low-cost API access matter to your use case, DeepSeek V4 is worth testing directly, especially given how aggressively priced its API remains relative to Western competitors. If you need built-in image generation, file analysis, or a more polished all-in-one interface without touching an API at all, ChatGPT’s free tier delivers more out of the box despite running on a smaller underlying model. For anything genuinely demanding, extended coding sessions, rigorous research, or complex multi-step reasoning, both free tiers are a step below what either company’s paid tier offers, and neither should be mistaken for a full substitute for DeepSeek V4 Pro or OpenAI’s Sol and Astra models.
Common Questions About DeepSeek V4 vs ChatGPT Free
Is DeepSeek V4 actually free to use?
Yes, through DeepSeek’s own chat interface with no subscription required. API access to V4 Pro and V4 Flash is paid, though priced well below most comparable Western model APIs.
What model does free ChatGPT actually use in 2026?
GPT-5.6 Luna, the smallest model in OpenAI’s current lineup, as of August 2026. There is no model picker on free accounts and no access to GPT-5.6 Sol or GPT-6 Astra without a paid subscription.
Why did DeepSeek V3 disappear from comparisons?
DeepSeek fully deprecated the V3.2 API endpoints, deepseek-chat and deepseek-reasoner, on July 24, 2026, replacing the lineup with the V4 family. Any comparison still built around V3 or V3.2 is describing a retired product.
Is it fair to compare DeepSeek V4 Pro to ChatGPT’s free tier?
Not directly, since V4 Pro’s full capability through the API is a paid product, even though DeepSeek’s chat interface gives free users meaningful access to the V4 family without a hard downgrade the way ChatGPT’s free tier restricts users to its smallest model specifically.
The Bottom Line
The comparison worth having in 2026 isn’t DeepSeek V3 against a generic “ChatGPT.” It’s DeepSeek V4, openly licensed and freely accessible through its own interface, against GPT-5.6 Luna, OpenAI’s deliberately scaled-down free-tier model. On that specific matchup, DeepSeek currently has the stronger claim to being the more capable free option, while ChatGPT’s advantage lies in the tools and interface wrapped around a smaller model rather than the model’s raw capability itself.
References and Sources
CodersEra, “DeepSeek V4 vs DeepSeek V3.2: What Changed?”: https://codersera.com/blog/deepseek-v4-vs-deepseek-v32-what-changed-developers-should-use/
ChatSmith, “DeepSeek Models: Full List, Features & Use Cases”: https://chatsmith.io/blogs/ai-guide/deepseek-models-overview-00381
DeepSeek AI, “DeepSeek V4 Explained: V4-Pro vs V4-Flash”: https://deepseek.ai/deepseek-v4
Engadget, “ChatGPT: What’s free in 2026 and what isn’t?”: https://www.engadget.com/2234173/chatgpt-free-features-2026/
PECollective, “ChatGPT Free Tier 2026: What You Get, What’s Limited, When to Upgrade”: https://pecollective.com/tools/chatgpt-free-tier-guide/
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