GPT-5.5 vs DeepSeek V4 Pro
OpenAI vs DeepSeek — DeepSeek V4 Pro is 91% cheaper on input and 97% cheaper on output, with nearly identical 1M context.
Pricing data verified: Jun 11, 2026
| Specification | GPT-5.5 | DeepSeek V4 Pro |
|---|---|---|
| Input Price (per 1M tokens) | $5.00 | $0.435 |
| Output Price (per 1M tokens) | $30.00 | $0.87 |
| Context Window | 1.05M tokens | 1M tokens |
| Tier | Premium | Budget |
| Provider | OpenAI | DeepSeek |
| Cost at 1M input + 500K output | $20.00 | $0.87 |
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Which Model for Which Use Case?
Massive Cost Savings
DeepSeek V4 Pro at $0.435/M input is 91% cheaper than GPT-5.5. For high-volume workloads, DeepSeek saves thousands per month.
Maximum Quality
GPT-5.5 is OpenAI's most capable model, offering the absolute highest quality reasoning. For applications where output quality is paramount, GPT-5.5 justifies its premium.
Startup & Scale
DeepSeek V4 Pro's 96% cost reduction makes it the go-to choice for startups and high-scale applications. Run 30x more queries for the same budget.
Enterprise Compliance
GPT-5.5 comes with OpenAI's enterprise compliance certifications, SOC 2, and dedicated support. For regulated industries, this matters.
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Frequently Asked Questions
Is DeepSeek V4 Pro cheaper than GPT-5.5?
Yes, dramatically. DeepSeek V4 Pro costs $0.435/M input and $0.87/M output. GPT-5.5 costs $5.00/M input and $30.00/M output. DeepSeek is 91% cheaper on input and 97% cheaper on output. For 1M input + 500K output/month, DeepSeek costs $0.87 vs GPT-5.5's $20.00 — saving $19.13/month (96%).
Which has a larger context window?
Both models offer effectively the same context size. GPT-5.5 has 1.05M tokens and DeepSeek V4 Pro has 1M tokens. The difference is negligible — both handle long documents and complex workflows with ease.
When should I choose GPT-5.5 over DeepSeek V4 Pro?
Choose GPT-5.5 when: (1) you need OpenAI's ecosystem and tooling, (2) you want the absolute highest quality reasoning, (3) your enterprise requires OpenAI compliance certifications, (4) cost is not a primary concern. Choose DeepSeek V4 Pro when: (1) cost matters (91-97% cheaper), (2) you want comparable quality at a fraction of the price, (3) your workload fits DeepSeek's capabilities.
Is DeepSeek V4 Pro production-ready?
DeepSeek V4 Pro supports production workloads with 1M context. It's used by thousands of companies for code generation, content creation, and analysis. The quality rivals GPT-5.5 at 3-7% of the cost, making it one of the best value propositions in AI APIs.