DeepSeek V4 vs GPT-5.5
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
DeepSeek · Mar 2026
The open-weights shock of 2026: ~81% SWE-bench Verified, a 1M context and MIT license at $0.30/$0.50 per million tokens.
OpenAI · Apr 2026
OpenAI's flagship reasoning model with a 1M-token context window, built for hard coding, science and long-horizon agentic work.
The verdict
GPT-5.5 wins 1 of the 1 benchmarks these models share, against 0 for DeepSeek V4. On price the gap is dramatic: DeepSeek V4 works out roughly 32x cheaper per blended million tokens. And DeepSeek V4 is open-weights (MIT), so it can be self-hosted — a structural advantage if data control or vendor independence matters.
Benchmark head-to-head 0–1
Specs & pricing
| DeepSeek V4 | GPT-5.5 | |
|---|---|---|
| modhub Index | — | 77.2 |
| Input price / 1M | $0.3 | $5 |
| Output price / 1M | $0.5 | $30 |
| Context window | 1M | 1M |
| Max output | 64K | 128K |
| Open weights | yes (MIT) | no |
| Reasoning model | yes | yes |
| Multimodal input | text | text, image |
| Knowledge cutoff | Dec 2025 | Jan 2026 |
| Released | Mar 2026 | Apr 2026 |
| Example monthly cost* | $3.75 | $95.00 |
* 10M input + 1.5M output tokens per month at list prices, no caching. Green = better value on that row.
Frequently asked questions
- Which is better, DeepSeek V4 or GPT-5.5?
- GPT-5.5 wins 1 of the 1 benchmarks these models share, against 0 for DeepSeek V4. On price the gap is dramatic: DeepSeek V4 works out roughly 32x cheaper per blended million tokens. And DeepSeek V4 is open-weights (MIT), so it can be self-hosted — a structural advantage if data control or vendor independence matters.
- Which is cheaper, DeepSeek V4 or GPT-5.5?
- DeepSeek V4 costs $0.3/$0.5 per million input/output tokens, while GPT-5.5 costs $5/$30. For a typical workload of 10M input and 1.5M output tokens per month, that's $3.75 versus $95.00.
- Which model is better for coding, DeepSeek V4 or GPT-5.5?
- On SWE-bench Verified — the standard agentic-coding benchmark — GPT-5.5 scores 82.6% versus ~81% for DeepSeek V4, making GPT-5.5 the stronger pick for coding agents.