Gemini 3.8 FlashvsGPT-5.1
Gemini 3.8 Flash is cheaper than GPT-5.1 at $0.75/M vs $1.25/M input tokens.
| Spec | Gemini 3.8 Flash | GPT-5.1 |
|---|---|---|
| Input price | $0.75/M tokens | $1.25/M tokens |
| Output price | $3.75/M tokens | $10/M tokens |
| Context window | 1.0M tokens | 400K tokens |
| Weights | Closed | Closed |
| Free API (OpenRouter) | No | No |
| Released | Sep 2026 | Nov 2025 |
Our Verdict
Gemini 3.8 Flash
GPT-5.1
Not enough votes to call it. On the specs, nothing separates them.
Too close to call
Reviewing agent-written code?See a Brief PR report
API pricing
Cost per 1M tokens
Gemini 3.8 Flash
Input
$0.75
1.7× cheaper
Output
$3.75
2.7× cheaper
GPT-5.1
Input
$1.25
Output
$10.00
Gemini 3.8 Flash is cheaper on both: 1.7× input, 2.7× output.
Where to run it
4 hosts
Gemini 3.8 Flash2 hosts
Per million tokens. Prices and uptime via OpenRouter, checked 13 Sep 2026.
Writing DNA
Style Comparison
Similarity
45%
Gemini 3.8 Flash
GPT-5.1
63%Vocabulary62%
20wSentence Length19w
0.17Hedging0.29
4.0Bold3.5
2.4Lists7.2
0.01Emoji0.00
0.84Headings0.61
0.06Transitions0.03
Based on 27 + 14 text responses
Research
What we learned reading every model
FAQ
Common questions
Keep exploring
More comparisons
GPT-5.1 vs Ox AlphaNew provider
GPT-5.1 vs Muse Spark 1.3New provider
GPT-5.1 vs Muse Spark 1.3 ContributorNew provider
GPT-5.1 vs MiniMax M3New provider
GPT-5.1 vs Seed 2.0 CodeNew provider
Gemini 3.8 Flash vs Seed 2.0 LiteNew provider
GPT-5.1 vs Seed 2.1 TurboNew provider
GPT-5.1 vs Sherlock Dash AlphaNew provider