Gemini 3.8 Flash vs GPT-5.1 Codex High: Specs & Benchmark Comparison
| Characteristic | Gemini 3.8 Flash | GPT-5.1 Codex High |
|---|---|---|
| Company | OpenAI | |
| Release Date | September 2, 2026 | November 11, 2025 |
| Parameters | — | — |
| Multimodal | Yes | Yes |
| Context (input) | 1.0M | 400K |
| Context (output) | 66K | 128K |
| Input Price / 1M | $0.75 | $1.25 |
| Output Price / 1M | $3.75 | $10.00 |
| Average Score | 0.6 | 1.0 |
Verdict
Gemini 3.8 Flash leads in 3 out of 4 comparison categories.
Overall Performance
Both models show comparable average scores: Gemini 3.8 Flash — 0.6, GPT-5.1 Codex High — 1.0.
API Cost
Gemini 3.8 Flash is 2.5x cheaper: input $0.75/1M vs $1.25/1M tokens.
Context Window
Gemini 3.8 Flash supports a larger context: 1M vs 400K tokens.
Recency
Gemini 3.8 Flash is newer: released 9/2/2026 vs 11/11/2025.
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Frequently Asked Questions
Which is better for coding — Gemini 3.8 Flash or GPT-5.1 Codex High?
Direct comparison on the SWE-Bench benchmark is not available. We recommend reviewing other metrics on the comparison page.
Which model is cheaper — Gemini 3.8 Flash or GPT-5.1 Codex High?
Gemini 3.8 Flash is cheaper for input: $0.75 per 1M tokens vs $1.25.
Which has a larger context window — Gemini 3.8 Flash or GPT-5.1 Codex High?
Gemini 3.8 Flash supports a larger context: 1,048,576 tokens vs 400,000.
The Gemini 3.8 Flash and GPT-5.1 Codex High 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-5.1 Codex High page. See also the complete list of AI model comparisons.