GPT-5 vs Gemini 2.5 Pro
Same price, 3.7x different context — when two mid-tier models cost exactly the same, context window becomes the tiebreaker. OpenAI vs Google.
Pricing data verified: Jun 6, 2026
| Specification | GPT-5 | Gemini 2.5 Pro |
|---|---|---|
| Input Price (per 1M tokens) | $1.25 | $1.25 |
| Output Price (per 1M tokens) | $10.00 | $10.00 |
| Context Window | 272K tokens | 1M tokens |
| Tier | Mid | Mid |
| Provider | OpenAI | |
| Cost at 1M input + 500K output | $6.25 | $6.25 |
| Context Ratio | 1x baseline | 3.7x more |
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Which Model for Which Use Case?
Long-Document Processing
Gemini 2.5 Pro's 1M context window can process entire codebases, legal contracts, or research papers in a single request. GPT-5's 272K context requires chunking for documents over ~200K tokens.
OpenAI Ecosystem Integration
GPT-5 integrates natively with OpenAI's Assistants API, function calling, and tool-use patterns. If your stack is built on OpenAI APIs, GPT-5 provides the smoothest integration path.
Code Review & Analysis
For codebases that exceed 272K tokens, Gemini 2.5 Pro can review entire repositories in one pass. GPT-5 excels at targeted code tasks within its context limit.
Multi-Turn Conversations
Chatbots with long conversation history benefit from Gemini 2.5 Pro's 1M context — it can hold ~7x more conversation turns before hitting limits. Both models cost the same per token.
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Frequently Asked Questions
Is GPT-5 or Gemini 2.5 Pro cheaper?
Neither — they cost exactly the same. Both GPT-5 and Gemini 2.5 Pro charge $1.25/M input tokens and $10.00/M output tokens. At 1M input + 500K output tokens/month, both cost $6.25. The difference is context window: Gemini 2.5 Pro offers 1M tokens (3.7x more than GPT-5's 272K).
Which has a larger context window, GPT-5 or Gemini 2.5 Pro?
Gemini 2.5 Pro has a 1M token context window, which is 3.7x larger than GPT-5's 272K token window. This makes Gemini 2.5 Pro significantly better for long-document processing, large codebases, and multi-turn conversations with extensive history.
When should I choose GPT-5 over Gemini 2.5 Pro?
Choose GPT-5 when you need OpenAI ecosystem integration (ChatGPT plugins, Assistants API), have workloads that fit within 272K context, prefer OpenAI's tool-use and function-calling patterns, or need GPT-5's specific strengths in coding and reasoning. Choose Gemini 2.5 Pro when you need larger context windows, Google ecosystem integration, or multimodal capabilities.
Can I use both GPT-5 and Gemini 2.5 Pro together?
Yes. Many production systems use both models: GPT-5 for tasks that benefit from OpenAI's tool ecosystem and function calling, and Gemini 2.5 Pro for long-context tasks like document analysis and code review. APIpulse's cost calculator can model multi-model setups to optimize your budget.