Gemini 2.5 Review: Models, Benchmarks & Pricing

Gemini 2.5 is the generation of Google models that began on March 25, 2025, when Google released Gemini 2.5 Pro and called it its most intelligent model yet. It was Google's first family of "thinking" models, built to reason before answering, and Gemini 2.5 Pro went straight to the top of the LMArena leaderboard. Over the following months the family grew to include Gemini 2.5 Flash, Flash-Lite, the image model nicknamed Nano Banana, and Deep Think mode.

This Gemini 2.5 review covers what the generation introduced, how the models perform, how Pro, Flash, and Flash-Lite compare, what they cost, and where they stand now that Gemini 3 and later models have arrived. Gemini 2.5 Pro and the rest of the family are available in Chat Smith on Android, iOS, and the web.

Gemini 2.5 is Google DeepMind's family of reasoning models that followed Gemini 2.0. Every model in the family can think through a problem step by step before it replies, works natively with text, images, audio, and video, and supports a context window of 1 million tokens. Their knowledge runs to January 2025.

The family has four main members: Gemini 2.5 Pro for deep reasoning, Gemini 2.5 Flash for fast everyday work, Gemini 2.5 Flash-Lite for the lowest cost, and Gemini 2.5 Flash Image, better known as Nano Banana, for creating and editing pictures.

Gemini 2.5 led Google's lineup until November 2025, when Gemini 3 arrived, as covered in our Gemini 3 review. Our guide to Gemini models shows how every generation fits together.

Four capabilities defined the Gemini 2.5 generation.

Gemini 2.5 Pro always reasons before answering, and the June 2025 version scored 88.0% on the AIME 2025 math test, 86.4% on GPQA Diamond, and 21.6% on Humanity's Last Exam without tools. Flash and Flash-Lite let developers set a thinking budget, trading depth for speed. That reasoning helps with the step-by-step problems an AI homework solver handles.

Gemini 2.5 reads images, audio, and video as easily as text, and its 1 million-token window can hold a long report, a large codebase, or about an hour of video at once. That makes it strong at summarizing recordings, explaining charts, and pulling details from long material, the kind of job tools that summarize YouTube videos rely on.

Announced at Google I/O in May 2025 and released to Google AI Ultra subscribers that August, Deep Think lets Gemini 2.5 explore several lines of reasoning in parallel before choosing an answer. A research version of the model reached gold-medal level at the 2025 International Mathematical Olympiad, one of the first AI systems to do so.

Released in August 2025, Gemini 2.5 Flash Image quickly went viral under the name Nano Banana. It edits photos from plain-language instructions, keeps the same person or character consistent across images, and can blend several pictures into one scene, which took it to the top of LMArena's image editing leaderboard.

The three text models share the same 1 million-token window but differ in depth, speed, and price. Prices are Google's API rates for prompts up to 200,000 tokens.

Flash offers the best balance for most people, while Pro is worth it when a task needs careful reasoning over a lot of material. Our Gemini 2.5 Pro review covers the flagship in more detail.

Gemini 2.5 Pro costs $1.25 per million input tokens and $10 per million output tokens for prompts up to 200,000 tokens, rising to $2.50 and $15 for longer prompts. Thinking tokens count as output. Nano Banana costs about $0.039 per generated image. Here is where each model is offered:

In Chat Smith, you can use the Gemini 2.5 family without a Google AI subscription or API key. Free accounts include limited use, and Chat Smith Pro raises usage limits for $9.99 per month or $39.99 per year.

Gemini 2.5 is no longer Google's newest generation. Gemini 3, Gemini 3.1 Pro, and several newer Flash models have followed, and in October 2026 Google launched Gemini 4 Argon. For the hardest tasks, those models now lead.

Thinking has a cost. Gemini 2.5 Pro cannot switch its reasoning off, so simple questions can take longer and use more tokens than they need to, and prompts over 200,000 tokens cost twice as much for input.

Its knowledge also stops in January 2025, and its benchmark scores come from Google's own testing. Images from Nano Banana carry an invisible SynthID watermark, and complex edits can still drift from what you asked, so check important results.

Chat Smith brings the whole Gemini 2.5 family into one app on Android, iOS, and the web. Pick a model from the model list and start chatting, with no Google account or subscription needed.

Use Gemini 2.5 Pro for research, analysis, and long documents. Gemini 2.5 Flash handles everyday writing and questions quickly, and Gemini 2.5 Flash-Lite is the fastest option for short, simple tasks.

When you want Google's newer models, switch to Gemini 3 Pro for text or Nano Banana Pro for images in the same chat. For research-heavy questions, the built-in Deep Research feature runs advanced search and reasoning across sources.

Gemini 2.5 was the generation where Google caught up and, for a while, pulled ahead: built-in reasoning, a 1 million-token context window, strong multimodal skills, Deep Think, and the viral Nano Banana image editor. Flash and Flash-Lite in particular remain fast, affordable choices for everyday work.

For the hardest reasoning, newer Gemini models are the better pick. You can try Gemini 2.5 and its successors side by side in Chat Smith, an AI chatbot that puts Google's models next to the latest from OpenAI, Anthropic, xAI, and DeepSeek.