GPT 5.1 vs o1-preview

GPT 5.1 vs o1-preview: GPT 5.1 is cheaper by 92% on average. GPT 5.1 from Azure OpenAI (272,000-token context, reasoning, tool calls) vs. o1-preview from Azure OpenAI (128,000-token context, reasoning, tool calls). Use Agent Command Center to A/B both in shadow mode and pick the winner per workload.

Side-by-side cost

Live workload comparison

Same workload run through both models. The cheaper one is highlighted.

3,000
0272,000
400
0128,000
5,000
01,000,000
GPT 5.1Cheaper
Azure OpenAI
$1,179/mo
Input $1.25/M · Output $10.00/M
Azure OpenAI
$10,501/mo
Input $15.00/M · Output $60.00/M
At this workload, GPT 5.1 is 89% cheaper than o1-preview — a savings of $9,321/month ($111,858/year).
Production recipe — Agent Command Center
strategy: cost-optimized
primary:
  model: gpt-5-1
  provider: azure-openai
fallback:
  model: o1-preview
  provider: azure-openai
shadow: { sample_rate: 0.05 }   # mirror 5% of traffic to compare quality live
GPT 5.1 o1-preview
Input price $1.25/M $15.00/M
Output price $10.00/M $60.00/M
Context window 272,000 128,000
Max output 128,000 32,768
Function calling
Vision
Audio input
Reasoning
Prompt caching
Structured output
Pricing verified May 12, 2026 May 12, 2026
Cheaper option
~92% cheaper than o1-preview
Larger context
272,000 tokens
More capabilities
5 of 6 capability flags advertised

Benchmark comparison

Side-by-side public benchmark scores. Greener bar = winner.

Chatbot Arena ELOgeneral
GPT 5.1
1,455
o1-preview
AIME 2025math
GPT 5.1
94.0%
o1-preview
GPQA Diamondreasoning
GPT 5.1
88.1%
o1-preview
MMMUmultimodal
GPT 5.1
85.4%
o1-preview
τ-bench (retail)agent
GPT 5.1
77.9%
o1-preview
SWE-bench Verifiedagent
GPT 5.1
76.3%
o1-preview
τ-bench (airline)agent
GPT 5.1
67.0%
o1-preview
FrontierMathmath
GPT 5.1
26.7%
o1-preview