Gemini 3.5 Flash vs GPT-5.5
API pricing, context window and capabilities for Gemini 3.5 Flash and GPT-5.5, side by side. Prices are the cheapest listed serving route per 1M tokens, from LiteLLM and OpenRouter.
Verdict
computed from the published numbersGemini 3.5 Flash wins on price. GPT-5.5 wins on Terminal-Bench, on intelligence and on context window.
Price
Gemini 3.5 Flash
Terminal-Bench
GPT-5.5
Intelligence
GPT-5.5
Context window
GPT-5.5
Key takeaways
who wins on what, from the published numbersGemini 3.5 Flash wins
- Cheaper input ($1.50 vs $5.00 /1M)
- Cheaper output ($9.00 vs $30.00 /1M)
- More serving providers (7 vs 6)
- Supports audio
GPT-5.5 wins
- Larger context window (1M vs 1.1M)
- Higher max output (66K vs 128K)
Cheaper overall
Gemini 3.5 Flash
$1.50 + $9.00 /1M
Larger context
GPT-5.5
1.1M
More providers
Gemini 3.5 Flash
7 providers
Pricing & specs
cheapest listed route · per 1M tokensOn-demand listed rates, OpenRouter routed quotes and Vercel reseller quotes. Enterprise commitments can be materially lower.
| Gemini 3.5 Flash | GPT-5.5 | |
|---|---|---|
| Input $/1M | $1.50via Google best | $5.00via OpenAI |
| Output $/1M | $9.00via Google best | $30.00via OpenAI |
| Context window | 1M | 1.1M best |
| Max output | 66K | 128K best |
| Serving providers | 7 best | 6 |
| Date | Released May 22, 2026 | Released Apr 23, 2026 |
Benchmarks
Benchmark scores, side by side| Gemini 3.5 Flash | GPT-5.5 | |
|---|---|---|
| Intelligence | 32.6 | 38.4 best |
| Terminal-Bench | 79% | 84% best |
| GPQA Diamond | 92% | 94% best |
| Output speed | 197 t/s best | 102 t/s |
| Latency (TTFT) | 17.14s best | 70.60s |
Cost calculator
choose a serving route for each sideInput tokens / month
Output tokens / month
Gemini 3.5 Flash
via OpenRouter
$17
GPT-5.5
via OpenAI
$55
Capabilities
feature support, side by side| Feature | Gemini 3.5 Flash | GPT-5.5 |
|---|---|---|
| Vision | ✓ | ✓ |
| Tool use | ✓ | ✓ |
| Reasoning | ✓ | ✓ |
| Audio | ✓ | — |
| Prompt caching | ✓ | ✓ |
| Structured output | ✓ | ✓ |
| Web search | ✓ | ✓ |
Related comparisons
Frequently asked questions
Which is cheaper, Gemini 3.5 Flash or GPT-5.5?
Gemini 3.5 Flash is cheaper for input ($1.50 vs $5.00 per 1M tokens) from Google. Gemini 3.5 Flash is cheaper for output ($9.00 vs $30.00 per 1M tokens) from Google.
What is the context window difference between Gemini 3.5 Flash and GPT-5.5?
Gemini 3.5 Flash has a 1M-token context window and GPT-5.5 has 1.1M tokens, so GPT-5.5 can take a larger prompt.
How do Gemini 3.5 Flash and GPT-5.5 compare on benchmarks?
On the tracked benchmarks, GPT-5.5 leads on Terminal-Bench, and GPT-5.5 leads on intelligence.
Listed prices from LiteLLM, OpenRouter and Vercel · last checked Oct 14, 2026
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