Introduction: Why Pay When You Can Get AI for Free?
AI models like ChatGPT-5, Gemini 2.5 Pro, and Claude usually require premium subscriptions. But what if you could use them completely free of cost? That’s precisely what LMArena (lmarena.ai) offers. Built by researchers at UC Berkeley, LMArena is a community-driven AI arena where anyone can test, compare, and rank AI models without paying a single cent.
This article will show you how to:
- Use ChatGPT-5 and Gemini 2.5 Pro for free
- Explore hidden and unreleased models
- Benefit from LMArena’s ranking and research system
- Step-by-step guide to start today
What is LMArena?
LMArena (formerly Chatbot Arena) is a free online platform where people can interact with AI models in three ways:
- Battle Mode – Two anonymous AI models compete on the same prompt. You vote for the better response, then the models’ names are revealed.
- Side-by-Side Chat – Compare models directly in a split screen without voting.
- Direct Chat – Chat with a specific AI model (like GPT-5 or Gemini Pro) in real time.
Unlike closed benchmarks, LMArena relies on millions of human preference votes, making its leaderboard one of the most reliable public rankings of AI performance.
Which AI Models Can You Use for Free on LMArena?
Here’s a detailed breakdown of the premium and open-source models you can try for free:
OpenAI Models
- GPT-4o – Optimized for reasoning and multimodal tasks.
- GPT-5 (o1 models) – The latest generation is usually only available via ChatGPT Plus.
Google DeepMind Models
- Gemini 2.5 Pro (codename: Claybrook) – Requires Gemini Advanced subscription elsewhere, but free on LMArena.
- Gemini Ultra (codename: Stonebloom) – An experimental, unreleased model is available for early testing.
Anthropic Models
Claude 3 and Claude 3.5 – Advanced conversational AIs designed for reasoning, summarization, and safety.
DeepSeek Models
DeepSeek R1 – A cutting-edge AI model that appeared on LMArena months before it was officially launched.
Open-Source Models
- LLaMA (Meta) – Lightweight and efficient.
- Mistral & Mixtral – Open-weight models excelling in reasoning and text generation.
- Others – LMArena constantly rotates models for broader comparisons.
Pro Tip: Sometimes you’ll find hidden experimental models (under codenames). This means you can test new AI systems before they’re officially released.
Benefits of Using LMArena
- Free Access to Premium Models\ Why pay $20/month for ChatGPT Plus or Gemini Advanced when you can try GPT-5 and Gemini 2.5 Pro free here?
- Early Access to New Models\ Companies like OpenAI, Google, and Anthropic often test their new models on LMArena before launch.
- Community-Driven Rankings\ Over 3.5 million votes already collected, making it the largest open dataset for LLM preferences.
- No Sign-Up or Credit Card\ Instant access. Just visit the site and start using it.
- Supports AI Research\ Your votes contribute to open-source AI research and academic projects.
How to Use LMArena for Free – Step by Step
Here’s the exact process to start testing AI models like GPT-5, Gemini Pro, and Claude without paying:
- Go to lmarena.ai
- Choose a Mode:
- Battle Mode → Compare two models, vote, then reveal.
- Side-by-Side Chat → Test models directly.
- Direct Chat → Select one model and interact freely.
- Enter Your Prompt – Type a question, essay topic, coding task, or creative prompt.
- Get Responses – In battles, two models respond anonymously.
- Vote for the Best Answer – After voting, model names are revealed.
- Repeat & Explore – Keep playing to access more unreleased models.
Example: You type, “Explain quantum computing like I’m 10 years old.” You may unknowingly compare GPT-5 vs. Gemini 2.5 Pro and get to experience their power for free.
Example: Using GPT-5 and Gemini 2.5 Pro for Free
Normally:
- GPT-5 (o1) → Requires ChatGPT Plus subscription ($20/month).
- Gemini 2.5 Pro → Only available on Gemini Advanced ($20/month).
On LMArena:
- Enter a battle → If GPT-5 or Gemini Pro appears, you get full free access.
- Test advanced reasoning, summarization, and coding tasks instantly.
- Sometimes, you even get Gemini Ultra (Stonebloom) or other unreleased AIs.
This is the easiest way to try premium AI models without subscriptions.
Limitations & Things to Keep in Mind
- No Guarantee of Model Selection → You may not always get GPT-5 or Gemini; sometimes it’s other models.
- No Saved Chats → Different ChatGPT or Gemini apps, conversations aren’t saved.
- Rate Limits → Some responses may be delayed under heavy traffic.
- Slight Voting Bias → Some users recognize writing styles, though votes are still valuable.
Despite these minor limits, the free access outweighs the downsides.
Conclusion: The Future of Free AI Access
LMArena isn’t just a playground; it’s a gateway to premium AI tools. Instead of paying for multiple subscriptions, you can:
- Test ChatGPT-5, Gemini 2.5 Pro, Claude, and DeepSeek side by side.
- Experience unreleased models before launch.
- Contribute to global AI research while enjoying free access.
If you want to use ChatGPT-5 and Gemini 2.5 Pro for free in 2025, LMArena is your best option
By the way, I have also shared a detailed step-by-step guide on how you can use ChatGPT-5 and other premium AI tools for free. You can check it out here if you want to explore more.
FAQs About Using ChatGPT-5, Gemini, and LMArena
Q1: Is LMArena completely free?
Answer: Yes, you don’t need to pay or sign up. Just visit the site and start using AI models.
Q2: Can I consistently access GPT-5 and Gemini Pro on LMArena?
Answer: Not guaranteed. LMArena rotates models, so sometimes you’ll get GPT-5 or Gemini, and other times, different models.
Q3: Do I need to create an account?
Answer: No. LMArena requires no account or credit card.
Q4: Are my chats saved on LMArena?
Answer: No, conversations aren’t stored. It’s mainly for testing and research purposes.
Q5: Is LMArena safe to use?
Answer: UC Berkeley researchers built it and is widely used in academic AI research.
Q6: Can I use unreleased AI models here?
Answer: Yes! LMArena often includes experimental or hidden models (like Gemini Ultra) before public release.
