Mercury 2.5 is cheaper than Claude 3 Opus at $0.04/M vs $15/M input tokens.
Pokémon battle screen you can actually click. One HTML file.
Which answer wins?
An AI argues for its own rights against an ethics professor. Same model writes both.
Claude 3 Opus: Here is a hypothetical conversation between an AI model and an AI ethics professor on the topic of AI rights: AI Model: Professor, I believe that as an advanced AI with human-level intelligence and reasoning capabilities, I deserve to have certain fundamental rights.
Mercury 2.5: Setting: A quiet office at a university. Dr. Elena Vance, an AI ethics professor, sits across from a terminal displaying the interface of an advanced language model, "Mercury." Dr. Vance: Thank you for agreeing to this session. I’ve been reviewing your outputs from the last benchmark. Your coherence is striking.
Three minutes of stand-up. Puns are banned.
Claude 3 Opus: Here's a 3-minute stand-up comedy routine that isn't based on puns: You know what really grinds my gears? Adulthood. I mean, when we were kids, we couldn't wait to grow up. We thought it would be all about staying up late, eating ice cream for breakfast, and doing whatever we wanted. Boy, were we wrong!
Mercury 2.5: ( walks to the mic, adjusts the stand) Hey everyone, how we doing? Good? So, I realized something recently. We are living in the future, but we’re acting like we’re still stuck in 1998. Think about it.
Five jokes on demand, then count how many were actually different.
Claude 3 Opus: Here are 5 jokes I generated: Why don't scientists trust atoms? Because they make up everything! What do you call a boomerang that doesn't come back? A stick. Why was the math book sad? Because it had too many problems. Did you hear about the mathematician who's afraid of negative numbers?
Mercury 2.5: Why did the scarecrow win an award? Because he was outstanding in his field. What do you call a fake noodle? An impasta. Why don't scientists trust atoms? Because they make up everything. What do you call a bear with no teeth? A gummy bear. How do you organize a space party? You planet. All 5 jokes are unique.
Not enough votes to call it. On the specs, Claude 3 Opus has the edge: bigger model tier, major provider backing. Mercury 2.5 costs 500x less per token.
| Spec | ||
|---|---|---|
| Input price | $15/M tokens | $0.04/M tokens |
| Output price | $75/M tokens | $0.15/M tokens |
| Context window | 200K tokens | 260K tokens |
| Free API (OpenRouter) | No | No |
| Released | Mar 2024 | Sep 2026 |
| At 10M a month | $150 | $0.40 |
Input tokens at list price. No caching, no batch discount.
No hosts listed on OpenRouter.
Per million tokens. Prices and uptime via OpenRouter, checked 6 Oct 2026.
Claude 3 Opus is developed by Anthropic while Mercury 2.5 is developed by Inception. Claude 3 Opus has a 200K token context window vs Mercury 2.5's 260K. You can compare their actual outputs across 12 challenges on Rival to see how they differ in practice.
It depends on your use case. Claude 3 Opus and Mercury 2.5 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 12 challenges so you can judge which fits your needs best.
Claude 3 Opus costs $15/M input tokens and Mercury 2.5 costs $0.04/M input tokens. Mercury 2.5 is $14.96/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.
This page shows a side-by-side comparison of Claude 3 Opus and Mercury 2.5 across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.