o3 vs Gemini 1.5 Flash
Pricing, context window, and benchmark comparison · Last updated April 2026
Gemini 1.5 Flash is cheaper than o3 at $0.07/1M/1M vs $10.00/1M/1M input tokens — a 133.3x cost difference. o3 scores higher on quality benchmarks (ELO 1380). Choose Gemini 1.5 Flash for cost-sensitive workloads; choose o3 for maximum quality.
Which is cheaper: o3 or Gemini 1.5 Flash?
Gemini 1.5 Flash is the cheaper option at $0.07/1M per 1M input tokens, compared to $10.00/1M for o3. That is a 133.3x cost difference on input tokens. Output pricing follows a similar pattern: o3 charges $40.00/1M/1M vs $0.30/1M/1M for Gemini 1.5 Flash.
Which has better quality: o3 or Gemini 1.5 Flash?
Based on LMSYS Chatbot Arena rankings, o3 achieves a higher ELO score (1380 vs 1211), suggesting stronger performance on open-ended tasks. o3 excels at highest reasoning benchmark scores of any model. Gemini 1.5 Flash is known for one of the cheapest high-quality models available.
Which should you choose: o3 or Gemini 1.5 Flash?
- → Highest reasoning benchmark scores of any model
- → Better cost-efficiency than o1 at similar quality
- → Superior at agentic and multi-step tasks
- → One of the cheapest high-quality models available
- → 1M token context window
- → Very fast inference
Frequently Asked Questions
Which is cheaper: o3 or Gemini 1.5 Flash?
Gemini 1.5 Flash is cheaper at $0.07/1M per 1M input tokens, making it 133.3x more affordable.
Which has better quality: o3 or Gemini 1.5 Flash?
o3 scores higher on the LMSYS Chatbot Arena with an ELO of 1380, suggesting better overall quality for most tasks.
Which has a larger context window: o3 or Gemini 1.5 Flash?
Gemini 1.5 Flash has a larger context window at 1000K tokens.
Should I choose o3 or Gemini 1.5 Flash?
Choose Gemini 1.5 Flash if cost is the priority. Choose o3 if benchmark quality is most important. Consider your specific use case: o3 is best for reasoning and math, while Gemini 1.5 Flash excels at low-cost and fast-response.
Is o3 or Gemini 1.5 Flash open source?
o3 is proprietary. Gemini 1.5 Flash is proprietary.