GPT 5.1 vs o3 (2025-04-16)

GPT 5.1 vs o3 (2025-04-16): o3 (2025-04-16) is cheaper by 38% on average. GPT 5.1 from Azure OpenAI (272,000-token context, reasoning, tool calls) vs. o3 (2025-04-16) from OpenAI (200,000-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
OpenAI
$1,400/mo
Input $2.00/M · Output $8.00/M
At this workload, GPT 5.1 is 16% cheaper than o3 (2025-04-16) — a savings of $221/month ($2,648/year).
Crossover: GPT 5.1 is cheaper when output/input ≤ 0.38 (input-heavy workloads — RAG, retrieval). o3 (2025-04-16) wins above (long-form generation).
Current workload ratio: 0.13 (400/3000)
Production recipe — Agent Command Center
strategy: cost-optimized
primary:
  model: gpt-5-1
  provider: azure-openai
fallback:
  model: o3-2025-04-16
  provider: openai
shadow: { sample_rate: 0.05 }   # mirror 5% of traffic to compare quality live
GPT 5.1 o3 (2025-04-16)
Input price $1.25/M $2.00/M
Output price $10.00/M $8.00/M
Context window 272,000 200,000
Max output 128,000 100,000
Function calling
Vision
Audio input
Reasoning
Prompt caching
Structured output
Pricing verified May 12, 2026 May 12, 2026
Cheaper option
~38% cheaper than GPT 5.1
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
o3 (2025-04-16)
AIME 2025math
GPT 5.1
94.0%
o3 (2025-04-16)
GPQA Diamondreasoning
GPT 5.1
88.1%
o3 (2025-04-16)
MMMUmultimodal
GPT 5.1
85.4%
o3 (2025-04-16)
τ-bench (retail)agent
GPT 5.1
77.9%
o3 (2025-04-16)
SWE-bench Verifiedagent
GPT 5.1
76.3%
o3 (2025-04-16)
τ-bench (airline)agent
GPT 5.1
67.0%
o3 (2025-04-16)
FrontierMathmath
GPT 5.1
26.7%
o3 (2025-04-16)