GPT-5.5 vs Gemini 3.1 Pro
Side-by-side comparison of API pricing, specs, benchmarks, and capabilities
|
by OpenAI
|
by Google
|
|
|---|---|---|
| Overview | ||
| Status | Current flagship | Current flagship |
| Released | Nov 15, 2025 | Nov 1, 2025 |
| Pricing per million tokens | ||
| Input | $5.00/Mtok | $2.00/Mtok |
| Output | $30.00/Mtok | $12.00/Mtok |
| Blended avg | $17.50/Mtok | $7.00/Mtok |
| Cached input | $0.500/Mtok | — |
| Specifications | ||
| Context window | 270K tokens | 2M tokens |
| Parameters | Proprietary | Proprietary |
| Speed (TPS) | — | — |
| Modalities | ||
| Input |
textimageaudio
|
textimageaudiovideo
|
| Benchmarks from Vellum LLM Leaderboard | ||
| Avg benchmark score | 64 | 79.3 |
| Perf / dollar | 3.7 | 11.3 |
| GPQA Diamond | — | 88 |
| SWE-Bench | — | 75 |
| HumanEval | — | 93 |
| MATH 500 | — | 95 |
| Providers | ||
| Available from |
OpenAI — $5.00/$30.00/Mtok
|
Google — $2.00/$12.00/Mtok
|
Cost at scale — 1M tokens (50/50 input/output)
| Volume | GPT-5.5 | Gemini 3.1 Pro | Savings |
|---|---|---|---|
| 1M tokens | $17.5 | $7 | $10.5 (60%) |
| 10M tokens | $175 | $70 | $105 (60%) |
| 100M tokens | $1750 | $700 | $1050 (60%) |
| 1000M tokens | $17500 | $7000 | $10500 (60%) |
Summary
GPT-5.5 by OpenAI costs $5.00/Mtok input and $30.00/Mtok output, with a 270K-token context window. It supports text, image, audio input.
Gemini 3.1 Pro by Google costs $2.00/Mtok input and $12.00/Mtok output, with a 2M-token context window. It supports text, image, audio, video input.
On a blended cost basis, Gemini 3.1 Pro is 150% cheaper than GPT-5.5. It also has a larger context window.
On benchmarks, Gemini 3.1 Pro scores higher (79.3 vs 64) on average. In terms of value, Gemini 3.1 Pro has better performance per dollar (11.3 vs 3.7).
Note: Pricing is per million tokens. Actual costs vary with usage patterns, prompt caching, and batch discounts. Always verify against official provider pricing pages.