Model Comparison
Gemini 1.5 Flash vs Gemini 2.5 Pro Preview 06-05Which is better in 2026?
Gemini 2.5 Pro Preview 06-05 significantly outperforms across most benchmarks. Gemini 1.5 Flash is 13.1x cheaper per token.
Verdict: Gemini 1.5 Flash vs Gemini 2.5 Pro Preview 06-05 — which is better?
Gemini 1.5 Flash (by Google) and Gemini 2.5 Pro Preview 06-05 (by Google) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.
Gemini 1.5 Flash outperforms in 0 benchmarks, while Gemini 2.5 Pro Preview 06-05 is better at 3 benchmarks (GPQA, MMMU, Vibe-Eval). Gemini 2.5 Pro Preview 06-05 significantly outperforms across most benchmarks.
On price, Gemini 1.5 Flash is roughly 13.1x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Choose Gemini 1.5 Flash if…
- cost matters — it's about 13.1x cheaper per token
Choose Gemini 2.5 Pro Preview 06-05 if…
- you want the strongest raw capability — it leads on 3 of 3 shared benchmarks
- you want the most recent training data — it shipped Jun 2025
Performance Benchmarks
Comparative analysis across standard metrics
Gemini 1.5 Flash outperforms in 0 benchmarks, while Gemini 2.5 Pro Preview 06-05 is better at 3 benchmarks (GPQA, MMMU, Vibe-Eval).
Gemini 2.5 Pro Preview 06-05 significantly outperforms across most benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, Gemini 1.5 Flash ($0.15/1M tokens) is 8.3x cheaper than Gemini 2.5 Pro Preview 06-05 ($1.25/1M tokens).
For output processing, Gemini 1.5 Flash ($0.60/1M tokens) is 16.7x cheaper than Gemini 2.5 Pro Preview 06-05 ($10.00/1M tokens).
In conclusion, Gemini 2.5 Pro Preview 06-05 is more expensive than Gemini 1.5 Flash.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Both models have the same input context window of 1,048,576 tokens. Gemini 2.5 Pro Preview 06-05 can generate longer responses up to 65,535 tokens, while Gemini 1.5 Flash is limited to 8,192 tokens.
Input Capabilities
Supported data types and modalities
Both Gemini 1.5 Flash and Gemini 2.5 Pro Preview 06-05 support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Gemini 1.5 Flash
Gemini 2.5 Pro Preview 06-05
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
Gemini 1.5 Flash was released on 2024-05-01, while Gemini 2.5 Pro Preview 06-05 was released on 2025-06-05.
Gemini 2.5 Pro Preview 06-05 is 13 months newer than Gemini 1.5 Flash.
May 1, 2024
2.2 years ago
Jun 5, 2025
1.1 years ago
1.1yr newerKnowledge Cutoff
When training data ends
Gemini 1.5 Flash has a knowledge cutoff of 2023-11-01, while Gemini 2.5 Pro Preview 06-05 has a cutoff of 2025-01-31.
Gemini 2.5 Pro Preview 06-05 has more recent training data (up to 2025-01-31), making it potentially better informed about events through that date compared to Gemini 1.5 Flash (2023-11-01).
Nov 2023
Jan 2025
1.2 yr newerProvider Availability
Gemini 1.5 Flash is available from Google. Gemini 2.5 Pro Preview 06-05 is available from Google.
Gemini 1.5 Flash
Gemini 2.5 Pro Preview 06-05
Outputs Comparison
Key Takeaways
Gemini 1.5 FlashGemini 2.5 Pro Preview 06-05Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against Gemini 1.5 Flash and Gemini 2.5 Pro Preview 06-05 side-by-side, then vote on the output you prefer.
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FAQ
Common questions about Gemini 1.5 Flash vs Gemini 2.5 Pro Preview 06-05.