Gemini 2.5 Flash vs GPT-5 nano

Gemini 2.5 Flash vs GPT-5 nano: GPT-5 nano is cheaper by 84% on average. Gemini 2.5 Flash from Google Vertex AI (1,048,576-token context, reasoning, tool calls) vs. GPT-5 nano from Azure OpenAI (272,000-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
01,048,576
400
0128,000
5,000
01,000,000
Google Vertex AI
$289/mo
Input $0.300/M · Output $2.50/M
GPT-5 nanoCheaper
Azure OpenAI
$47.18/mo
Input $0.0500/M · Output $0.400/M
At this workload, GPT-5 nano is 84% cheaper than Gemini 2.5 Flash — a savings of $242/month ($2,904/year).
Production recipe — Agent Command Center
strategy: cost-optimized
primary:
  model: gpt-5-nano
  provider: azure-openai
fallback:
  model: gemini-2-5-flash
  provider: vertex-ai
shadow: { sample_rate: 0.05 }   # mirror 5% of traffic to compare quality live
Gemini 2.5 Flash GPT-5 nano
Input price $0.300/M $0.0500/M
Output price $2.50/M $0.400/M
Context window 1,048,576 272,000
Max output 65,535 128,000
Function calling
Vision
Audio input
Reasoning
Prompt caching
Structured output
Pricing verified May 12, 2026 May 12, 2026
Cheaper option
~84% cheaper than Gemini 2.5 Flash
Larger context
1,048,576 tokens
More capabilities
5 of 6 capability flags advertised

Benchmark comparison

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

Chatbot Arena ELOgeneral
Gemini 2.5 Flash
1,335
GPT-5 nano
1,325
HumanEvalcode
Gemini 2.5 Flash
87.0%
GPT-5 nano
86.3%
MMLU-Proreasoning
Gemini 2.5 Flash
75.0%
GPT-5 nano
73.0%
GPQA Diamondreasoning
Gemini 2.5 Flash
68.4%
GPT-5 nano
AIME 2024math
Gemini 2.5 Flash
60.0%
GPT-5 nano