tokevenGPTvsGemini
GPT 5.1 vs Gemini 3.5 Flash
Side-by-side comparison of pricing, task quality, and projected cost at higher scale.
Pricing
Side-by-side pricing
GPT 5.1
Mid-tierGemini 3.5 Flash
Fast / BudgetInput $/MTok
$1.25
$1.50
Output $/MTok
$10.00
$9.00
Cache discount
90% off
90% off
Context
272K
1,048.576K
Quality
Task confidence comparison
Confidence score from zero to one hundred by task type, where higher is better.
Code Generation
0
vs
68
Code Review
0
vs
65
Summarization
0
vs
85
Q&A
0
vs
84
Extraction
0
vs
90
Reasoning
0
vs
60
Classification
0
vs
92
Creative Writing
0
vs
55
GPT 5.1
Gemini 3.5 Flash
Guidance
When to use GPT 5.1 vs Gemini 3.5 Flash
Choose GPT 5.1 when...
- -Cost matters: 17% cheaper on input tokens
Choose Gemini 3.5 Flash when...
- -You need a larger context window (1,048.576K vs 272K)
- Similar performance; consider provider preference or ecosystem fit.
At scale
Cost at scale
Estimated cost assuming a seventy percent input and thirty percent output token split.
GPT 5.1
Gemini 3.5 Flash
100K tokens
$0.39
$0.38Cheaper
1M tokens
$3.88
$3.75Cheaper
10M tokens
$38.75
$37.50Cheaper
FAQ
When should I use GPT 5.1 instead of Gemini 3.5 Flash?
GPT 5.1 and Gemini 3.5 Flash perform similarly across all tracked tasks. Pick based on pricing and provider preference.
Is Gemini 3.5 Flash cheaper than GPT 5.1?
Gemini 3.5 Flash input costs $1.50/MTok, which is 20% more than GPT 5.1 at $1.25/MTok.
What are the context window sizes for GPT 5.1 and Gemini 3.5 Flash?
GPT 5.1 has a 272K token context window. Gemini 3.5 Flash has a 1,048.576K token context window.
Go deeper on either model
Per-call cost calculators, provider lineups, and price history for both models on this page.
Other comparisons
How GPT 5.1 and Gemini 3.5 Flash stack up against the rest of the field.
Track your real costs
Comparisons show estimated costs at list price. The dashboard reveals your real spend and savings.