Condensed Comparison: OpenAI GPT-5 vs. Google Gemini 2.5 API Costs in 2025

 Condensed Comparison: OpenAI GPT-5 vs. Google Gemini 2.5 API Costs in 2025

As of November 2025, OpenAI's GPT-5 series and Google's Gemini 2.5 models lead in LLM APIs, offering multimodal capabilities at token-based rates. This summary compares flagship and lightweight options, analyzes a sample workload, and notes optimization tips—drawn from official sources. Pricing Overview

Provider	Model	Input ($/1M tokens)	Output ($/1M tokens)	Context Window
OpenAI	GPT-5.1	1.25	10.00	Not specified
OpenAI	GPT-5 mini	0.25	2.00	Not specified
Google	Gemini 2.5 Pro	1.25 (≤200K); 2.50 (>200K)	10.00 (≤200K); 15.00 (>200K)	200K+
Google	Gemini 2.5 Flash	0.30 (text/image/video)	2.50	1M

Batch processing: Up to 50% off for both. Multimodal extras: Gemini adds audio/video rates; OpenAI caching at 10% of standard input. Sample Workload: 5M Input + 0.5M Output Tokens/Month

Provider	Model	Total Cost ($)	Cheaper vs. OpenAI Flagship?
OpenAI	GPT-5.1	11.25	Baseline
OpenAI	GPT-5 mini	2.25	80% cheaper
Google	Gemini 2.5 Pro	11.25	Equal
Google	Gemini 2.5 Flash	2.75	76% cheaper

Gemini edges out for lightweight tasks due to multimodal perks; GPT-5 shines in reasoning benchmarks. Key Factors & Tips

• Performance: GPT-5 for complex reasoning; Gemini for speed and long contexts.
• Savings: Use caching (OpenAI: 90% off cached input; Gemini: $0.03-0.25/1M). Optimize prompts to stay under tiers.
• Conclusion: Gemini 2.5 Flash is often cheapest for volume; test via free tiers.

Pricing as of Nov 2025—check officials for updates.Top 5 References

1. OpenAI API Pricing - https://openai.com/api/pricing/
2. Gemini Developer API Pricing - https://ai.google.dev/gemini-api/docs/pricing
3. LLM API Pricing Comparison (2025) - https://intuitionlabs.ai/articles/llm-api-pricing-comparison-2025
4. Gemini AI Pricing: What You'll Really Pay In 2025 - https://www.cloudzero.com/blog/gemini-pricing/
5. OpenAI Platform Pricing Docs - https://platform.openai.com/docs/pricing