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Gemini 2.5 ProvsGemini 1.5 Pro

Google DeepMind vs Google DeepMind — Side-by-side model comparison

Gemini 2.5 Pro leads 2/5 categories

Head-to-Head Comparison

MetricGemini 2.5 ProGemini 1.5 Pro
Provider
Google DeepMind
Google DeepMind
Arena Rank
#4
#4
Context Window
1M
1M
Input Pricing
$1.25/1M tokens
$3.50/1M tokens
Output Pricing
$10.00/1M tokens
$10.50/1M tokens
Parameters
Undisclosed
Undisclosed
Open Source
No
No
Best For
Long documents, multimodal, reasoning
Long documents, multimodal analysis, coding
Release Date
May 14, 2024

Gemini 2.5 Pro

Gemini 2.5 Pro is Google DeepMind's most capable AI model, featuring an industry-leading 1 million token context window that can process entire books, codebases, or hours of video in a single request. Built with native multimodal capabilities, it understands text, images, audio, and video natively rather than through separate encoders. The model demonstrates exceptional performance on coding benchmarks, mathematical reasoning, and multi-step planning tasks. Its massive context window makes it uniquely suited for tasks involving large document analysis, repository-scale code understanding, and long video comprehension. Gemini 2.5 Pro also features built-in 'thinking' capabilities similar to reasoning models, allowing it to tackle complex problems with improved accuracy. Available through Google AI Studio and Vertex AI.

Gemini 1.5 Pro

Gemini 1.5 Pro, developed by Google DeepMind, is a high-capability multimodal model with a 1 million token context window that can process entire books, codebases, or hours of video in a single request. The model uses a Mixture-of-Experts architecture to deliver strong performance on complex reasoning, coding, mathematical analysis, and multimodal understanding tasks. Its massive context window makes it uniquely suited for tasks involving large-scale document analysis, repository-wide code review, and comprehensive media processing. Priced at $3.50 per million input tokens and $10.50 per million output tokens, it offers substantial context capacity at competitive pricing. Gemini 1.5 Pro ranks #4 on the Chatbot Arena leaderboard, reflecting its position as one of the most capable models available for tasks requiring deep, contextual understanding.

Key Differences: Gemini 2.5 Pro vs Gemini 1.5 Pro

1

Gemini 2.5 Pro is 1.2x cheaper on average, making it the better choice for high-volume applications.

G

When to use Gemini 2.5 Pro

  • +Budget is a concern and you need cost efficiency
  • +Your use case involves long documents, multimodal, reasoning
View full Gemini 2.5 Pro specs →
G

When to use Gemini 1.5 Pro

  • +Quality matters more than cost
  • +Your use case involves long documents, multimodal analysis, coding
View full Gemini 1.5 Pro specs →

Cost Analysis

At current pricing, Gemini 2.5 Pro is 1.2x more affordable than Gemini 1.5 Pro. For a typical enterprise workload processing 100M tokens per month:

Gemini 2.5 Pro monthly cost

$563

100M tokens/mo (50/50 in/out)

Gemini 1.5 Pro monthly cost

$700

100M tokens/mo (50/50 in/out)

The Verdict

Gemini 2.5 Pro wins our head-to-head comparison with 2 out of 5 category wins. It's the stronger choice for long documents, multimodal, reasoning, though Gemini 1.5 Pro holds an edge in long documents, multimodal analysis, coding.

Last compared: April 2026 · Data sourced from public benchmarks and official pricing pages

Frequently Asked Questions

Which is better, Gemini 2.5 Pro or Gemini 1.5 Pro?
In our head-to-head comparison, Gemini 2.5 Pro leads in 2 out of 5 categories (arena rank, context window, input pricing, output pricing, and parameters). Gemini 2.5 Pro excels at long documents, multimodal, reasoning, while Gemini 1.5 Pro is better suited for long documents, multimodal analysis, coding. The best choice depends on your specific requirements, budget, and use case.
How does Gemini 2.5 Pro pricing compare to Gemini 1.5 Pro?
Gemini 2.5 Pro charges $1.25 per 1M input tokens and $10.00 per 1M output tokens. Gemini 1.5 Pro charges $3.50 per 1M input tokens and $10.50 per 1M output tokens. Gemini 2.5 Pro is the more affordable option, approximately 1.2x cheaper on average. For high-volume production workloads, the pricing difference can significantly impact total cost of ownership.
What is the context window difference between Gemini 2.5 Pro and Gemini 1.5 Pro?
Gemini 2.5 Pro supports a 1M token context window, while Gemini 1.5 Pro supports 1M tokens. Context window size matters most for tasks involving long documents, large codebases, or extended conversations.
Can I use Gemini 2.5 Pro or Gemini 1.5 Pro for free?
Gemini 2.5 Pro is a paid API model starting at $1.25 per 1M input tokens. Gemini 1.5 Pro is a paid API model starting at $3.50 per 1M input tokens.
Which model has better benchmarks, Gemini 2.5 Pro or Gemini 1.5 Pro?
Gemini 2.5 Pro holds arena rank #4, while Gemini 1.5 Pro holds rank #4. Note that benchmarks don't capture every use case — we recommend testing both models on your specific tasks.
Is Gemini 2.5 Pro or Gemini 1.5 Pro better for coding?
Gemini 2.5 Pro's primary strength is long documents, multimodal, reasoning. Gemini 1.5 Pro is specifically optimized for coding tasks. For coding specifically, arena rank and code-specific benchmarks are the best indicators of performance.