GPT-5.1 vs Gemini 3.5 Flash: Pricing Comparison
Compare pricing, capabilities, and costs for your LLM workloads.
OpenAI
GPT-5.1
Pricing (per 1M tokens)
Input$1.25
Output$10.00
Cached Input$0.1250
Context & Output
Context Window400K tokens
Max Output128K tokens
Capabilities
Categoryflagship
Multimodaltext + image
Fine-tuningNo
StreamingYes
Gemini 3.5 Flash
Pricing (per 1M tokens)
Input$1.50
Output$9.00
Cached Input$0.1500
Batch Input$0.7500
Batch Output$4.50
Context & Output
Context Window1M tokens
Max Output65.5K tokens
Capabilities
Categorymid
Multimodaltext + image + audio
Fine-tuningNo
StreamingYes
Quick Verdict
Cheaper Input Price
GPT-5.1
16.7% cheaper
Cheaper Output Price
Gemini 3.5 Flash
10.0% cheaper
Larger Context Window
Gemini 3.5 Flash
+600K tokens
Cost Comparison
Sample workload: 1,000,000 input tokens + 1,000,000 output tokens
GPT-5.1
$11.25
$1.25/1M input + $10.00/1M output
Gemini 3.5 Flash
$10.50
$1.50/1M input + $9.00/1M output
Gemini 3.5 Flash is 6.7% cheaper for this workload.
Frequently Asked Questions
Which is cheaper, GPT-5.1 or Gemini 3.5 Flash?
For input tokens, GPT-5.1 is cheaper at $1.25 per 1M tokens. For output tokens, Gemini 3.5 Flash is cheaper at $9.00 per 1M tokens. The overall cost depends on your workload's input/output ratio.
What is the context window size of GPT-5.1 vs Gemini 3.5 Flash?
GPT-5.1 has a context window of 400K tokens, while Gemini 3.5 Flash has 1M tokens. Gemini 3.5 Flash supports a larger context window of 1M tokens, which is beneficial for processing longer documents.
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