GPT-5.5 Pro vs DeepSeek V4 Pro
OpenAI vs DeepSeek — DeepSeek V4 Pro is 99% cheaper on both input and output, with the same 1M context window.
Pricing data verified: Jun 21, 2026
| Specification | GPT-5.5 Pro | DeepSeek V4 Pro |
|---|---|---|
| Input Price (per 1M tokens) | $30.00 | $0.435 |
| Output Price (per 1M tokens) | $180.00 | $0.87 |
| Context Window | 1.05M tokens | 1M tokens |
| Tier | Premium | Budget |
| Provider | OpenAI | DeepSeek |
| Input Savings | Baseline | 98.5% cheaper |
| Output Savings | Baseline | 99.5% cheaper |
| Cost at 1M input + 500K output | $120.00 | $0.87 |
Calculate Your Exact Costs
Enter your usage to see a precise cost comparison for both models.
Which Model for Which Use Case?
Cost-Sensitive Workloads
DeepSeek V4 Pro is 99% cheaper across the board. At $0.435/M input vs $30.00/M, it delivers strong quality at 1.5% of the cost. For most production workloads, DeepSeek is the clear winner.
Premium Reasoning Tasks
GPT-5.5 Pro's enhanced chain-of-thought reasoning excels at complex multi-step analytical tasks. If your use case demands the absolute highest quality reasoning and cost is secondary, GPT-5.5 Pro is the choice.
Enterprise Cost Optimization
At 1M requests/month, DeepSeek V4 Pro saves $1,430/year compared to GPT-5.5 Pro. For enterprise-scale deployments, the 99% cost difference translates to massive annual savings.
Startup MVPs & Prototypes
When building an MVP or prototype, DeepSeek V4 Pro lets you iterate at near-zero cost. At $0.87 for 1M input + 500K output, you can run thousands of experiments for the price of a single GPT-5.5 Pro request.
Need deeper cost analysis?
APIpulse Pro lets you compare all 42 models, save scenarios, and export PDF reports.
Frequently Asked Questions
Is DeepSeek V4 Pro really that much cheaper than GPT-5.5 Pro?
Yes, dramatically so. DeepSeek V4 Pro costs $0.435/M input (98.5% cheaper than GPT-5.5 Pro's $30.00) and $0.87/M output (99.5% cheaper than GPT-5.5 Pro's $180.00). For output-heavy workloads, DeepSeek V4 Pro is roughly 207x cheaper.
What's the quality difference between GPT-5.5 Pro and DeepSeek V4 Pro?
GPT-5.5 Pro is OpenAI's most capable model with enhanced chain-of-thought reasoning, generally outperforming DeepSeek V4 Pro on complex multi-step tasks. DeepSeek V4 Pro offers strong quality for most production workloads — coding, text analysis, summarization, and general chat — at a fraction of the cost. For many use cases, the 99% cost savings far outweigh any quality difference.
When should I choose GPT-5.5 Pro over DeepSeek V4 Pro?
Choose GPT-5.5 Pro when: (1) you need the absolute best reasoning capabilities, (2) cost is not a primary concern, (3) you need enhanced chain-of-thought for complex multi-step problems. Choose DeepSeek V4 Pro when: (1) you want 99% cost savings, (2) similar context windows (1M) meet your needs, (3) you need strong quality at a fraction of the price.
How much would I save switching from GPT-5.5 Pro to DeepSeek V4 Pro?
For a typical workload of 1M input + 500K output tokens/month, GPT-5.5 Pro costs $120.00 vs DeepSeek V4 Pro's $0.87 — saving $119.13/month (99.3%). At scale (10M input + 5M output), you save $1,191.30/month — over $14,000/year.