Gemini 3.8 Flash vs GPT-5.6 Terra: Specs & Benchmark Comparison
Gemini 3.8 Flash is developed by Google, while GPT-5.6 Terra comes from OpenAI. GPT-5.6 Terra was released in July 2026, and Gemini 3.8 Flash followed 2 months later in September 2026.
The two models share 5 published benchmarks. Gemini 3.8 Flash leads on 4 of them, GPT-5.6 Terra on 1. The widest gaps are on GDP.pdf, where Gemini 3.8 Flash scores 35.0% against 24.7%; OSWorld 2.0, where Gemini 3.8 Flash scores 59.0% against 50.2%. Averaged across everything we track, Gemini 3.8 Flash sits at 59.2% and GPT-5.6 Terra at 59.0%.
Gemini 3.8 Flash is the cheaper API at $0.75 per million input tokens and $3.75 per million output tokens, roughly 3 times cheaper than GPT-5.6 Terra at $2 and $12. Both accept a context window of about 1M tokens. Gemini 3.8 Flash accepts text, images, audio, and video as input, while GPT-5.6 Terra accepts text and images.
| Characteristic | Gemini 3.8 Flash | GPT-5.6 Terra |
|---|---|---|
| Company | OpenAI | |
| Release Date | September 2, 2026 | July 9, 2026 |
| Parameters | — | — |
| Multimodal | Yes | Yes |
| Context (input) | 1.0M | 1.1M |
| Context (output) | 66K | 128K |
| Input Price / 1M | $0.75 | $2.00 |
| Output Price / 1M | $3.75 | $12.00 |
| Average Score | 59.2% | 59.0% |
| Benchmarks | ||
| GDP.pdf | 35.0% | 24.7% |
| OSWorld 2.0 | 59.0% | 50.2% |
| DeepSWE 1.1 | 73.7% | 70.0% |
| Terminal-Bench 4.0 | 19.1% | 21.5% |
| Terminal-Bench 2.1 | 89.4% | 87.4% |
Visual Benchmark Comparison
Verdict
Gemini 3.8 Flash leads in 2 out of 4 comparison categories.
Both models show comparable average scores: Gemini 3.8 Flash — 0.6, GPT-5.6 Terra — 0.6.
Gemini 3.8 Flash is 3.1x cheaper: input $0.75/1M vs $2.00/1M tokens.
GPT-5.6 Terra supports a larger context: 1M vs 1M tokens.
Gemini 3.8 Flash is newer: released 9/2/2026 vs 7/9/2026.
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Frequently Asked Questions
Which is better for coding — Gemini 3.8 Flash or GPT-5.6 Terra?
Which model is cheaper — Gemini 3.8 Flash or GPT-5.6 Terra?
Which has a larger context window — Gemini 3.8 Flash or GPT-5.6 Terra?
The Gemini 3.8 Flash and GPT-5.6 Terra comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the Gemini 3.8 Flash or GPT-5.6 Terra page. See also the complete list of AI model comparisons.