ChatGPT vs DeepSeek-V4: Which AI Tool is Better?

ChatGPT and DeepSeek are often compared on price, but the gap has changed. OpenAI's cheapest GPT-6 model now costs less per token than DeepSeek's API, so the real differences today are features, openness and where your data goes.

ChatGPT

Since October 2026, every ChatGPT plan runs GPT-6: free and Go users get GPT-6 Luna, and paid plans get the stronger GPT-6 Sol. ChatGPT handles images and voice, generates images, browses the web, and now answers with interactive elements such as charts and calculators. Plus costs $20 a month. For developers, OpenAI's API ranges from GPT-6 Luna at $0.10 per million input tokens and $0.50 per million output tokens up to GPT-6 Astra at $10 and $50.

DeepSeek

DeepSeek offers a free chat app and an OpenAI-compatible API. Its current models are the V4 series; the V4.1 Flash update in October 2026 released MIT-licensed open weights and posted strong coding results, with third-party reports putting it at 77.0 on DeepSWE. Hosted through OpenRouter it costs about $0.15 per million input tokens and $0.60 per million output tokens. The open weights are its biggest advantage: you can run the model on your own infrastructure. The main concern for regulated industries is that DeepSeek's own service is operated in China, which raises data residency questions; self-hosting avoids that.

Key differences

	ChatGPT	DeepSeek
Free plan	Yes, GPT-6 Luna	Yes, web chat
Paid plan	Plus $20/month (GPT-6 Sol)	No consumer subscription
Cheapest API (per 1M in/out)	GPT-6 Luna $0.10 / $0.50	V4.1 Flash about $0.15 / $0.60 (OpenRouter)
Open weights	No	Yes, MIT license
Images, voice, interactive answers	Yes	More limited
Data location	US-based company	Operated from China (self-hosting avoids this)

Which to choose

Choose ChatGPT if you want a single assistant for writing, research, images and voice, or a team plan with familiar admin controls. The free tier is now strong enough for everyday use, and our GPT-6 rollout guide covers what Plus adds.

Choose DeepSeek if you are a developer who needs open weights: to self-host for data control, fine-tune on your own data, or avoid vendor lock-in. If you only need a cheap hosted API, compare it against GPT-6 Luna and Claude Haiku 5.5, which now match or beat it on list price.