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  1. Home/
  2. Compare/
  3. Claude 3 Opus vs Mercury 2.5
Updated Sep 2026

Claude 3 Opus vs Mercury 2.5

Mercury 2.5 is cheaper than Claude 3 Opus at $0.04/M vs $15/M input tokens.

Pokémon Battle UI Recreation

Pokémon battle screen you can actually click. One HTML file.

Loading the build
Claude 3 Opus
Loading the build
Mercury 2.5

Which answer wins?

Written rounds

3 prompts
  • 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.

    Every model's answer to this prompt
  • 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.

    Every model's answer to this prompt
  • 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.

    Every model's answer to this prompt

Price and specs

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.

Claude 3 Opus and Mercury 2.5 compared across 12 shared prompts
SpecClaude 3 OpusMercury 2.5
Input price$15/M tokens$0.04/M tokens
Output price$75/M tokens$0.15/M tokens
Context window200K tokens260K tokens
Free API (OpenRouter)NoNo
ReleasedMar 2024Sep 2026
At 10M a month$150$150$0.40$0.40
1M10M100M1B10M tokens

Input tokens at list price. No caching, no batch discount.

Where to run it1 host
Claude 3 Opus

No hosts listed on OpenRouter.

Mercury 2.51 host
HostInOutContextUptime
  • Inception$0.04 in·$0.15 out·260k·99.4% up

Per million tokens. Prices and uptime via OpenRouter, checked 6 Oct 2026.

Common questions

What is the difference between Claude 3 Opus and Mercury 2.5?

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.

Which is better, Claude 3 Opus or Mercury 2.5?

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.

How much does Claude 3 Opus cost compared to Mercury 2.5?

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.

How can I compare Claude 3 Opus and Mercury 2.5 on Rival?

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.

More comparisons

Against the newest arrivals

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  • Mercury 2.5 vs Qwen3.8 Omni FlashLanded Sep 2026

Same lab, same size, long tail

  • Claude 3 Opus vs Claude Sonnet 5.5Version compare
  • Claude 3 Opus vs Claude Opus 5.5Same lab
  • Mercury 2.5 vs Mercury 2.5 PreviewSame lab
  • Mercury 2.5 vs MercurySame lab
  • Mercury 2.5 vs Claude 3 HaikuCross-provider
  • Mercury 2.5 vs Claude 3 SonnetSame size
  • Mercury 2.5 vs Claude Sonnet 3.6 (2022-10-22)Same size
  • Mercury 2.5 vs Claude 3.7 SonnetSame size

Model pages

  • Claude 3 Opus12 outputs, specs and price
  • Mercury 2.558 outputs, specs and price
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