Anthropic Evals
Run your actual prompts against Claude Opus, Sonnet, and Haiku to see which model fits your workload. Compare Claude against GPT, Gemini, and open source in the same session.
Why Evaluate Claude Models Yourself?
Anthropic's Claude lineup spans from Haiku (fast and cheap) to Opus (most capable). Each model has different strengths, and the price differences are significant. A prompt that needs Opus-level reasoning might work just as well on Sonnet at a fraction of the cost.
The only way to know is to test with your own prompts and compare the outputs directly.
Common Claude Model Comparisons
These are the evaluations teams run most often when working with Anthropic's models.
Claude Opus 4 vs Claude Sonnet 4
Opus is more capable but slower and more expensive. For many tasks, Sonnet produces equivalent results. Test your hardest prompts to see where the gap actually matters.
Good for: Deciding if you need the top-tier model or if Sonnet is enough
Claude Sonnet 4 vs Claude Haiku
Haiku is significantly cheaper and faster. For classification, extraction, and routing tasks, it often performs as well as Sonnet. Run your high-volume prompts through both to find the cost/quality boundary.
Good for: High-volume tasks, optimizing API costs
Current vs Previous Generation
Anthropic regularly releases new model versions. Compare the latest Sonnet against the previous release to verify that upgrades improve your specific use case before migrating.
Good for: Migration decisions, regression testing
Extended Thinking vs Standard
Claude's extended thinking mode takes longer but produces better results on complex reasoning tasks. Compare standard and extended thinking outputs to see if the extra latency is worth it for your prompts.
Good for: Math, analysis, multi-step reasoning
Claude vs Other Providers
Comparing within Anthropic's lineup only tells you part of the story. Test Claude models against the competition to see if you're getting the best results for the price.
Claude Sonnet vs GPT-4.1
Two flagships at similar price points. Compare them on writing, coding, and instruction following to see which fits your needs.
Claude Opus vs o3
The top reasoning models from Anthropic and OpenAI. Test your most complex prompts to see which handles them better.
Claude Haiku vs Gemini Flash
Both are fast and affordable. If you're optimizing for speed and cost, compare these two on your workload.
Claude vs Open Source
For simpler tasks, local models via Ollama might be free and good enough. Compare to find the threshold.
Evvl vs Anthropic Console
Anthropic's Console includes a Workbench for testing prompts against Claude models. Here's how it compares to Evvl.
| Feature | Anthropic Console | Evvl |
|---|---|---|
| Supported providers | Anthropic only | OpenAI, Anthropic, Google, OpenRouter, Ollama, LM Studio |
| Cross-provider comparison | No | Yes |
| Side-by-side output | One model at a time | Multiple models simultaneously |
| Prompt iteration tools | Yes (prompt generator, variables) | No |
| Local model support | No | Yes (Ollama, LM Studio) |
| Desktop app | No (web only) | Yes (Mac, Windows, Linux) |
| Best for | Iterating on prompts for a specific Claude model | Choosing which model to use across providers |
| Price | Free (with API usage costs) | Free |
Use Anthropic's Console to refine prompts for a specific Claude model. Use Evvl to compare Claude against other providers and find the right model in the first place.
How to Evaluate Claude Models with Evvl
- 1 Add your Anthropic API key
Get one from console.anthropic.com. Your key is stored locally and never saved on our servers.
- 2 Pick the models you want to compare
Select any combination of Claude models. You can also mix in GPT, Gemini, and others for cross-provider evals.
- 3 Write your prompt and run
Use your real prompts, the ones you'd actually use in production. Evvl sends the same prompt to every selected model simultaneously.
- 4 Compare results side by side
See every response at once instead of switching tabs or copy-pasting between windows.
Frequently Asked Questions
Which Claude model should I use?
Sonnet is the best starting point for most tasks. Use Opus when you need the highest quality on complex reasoning or nuanced writing. Use Haiku when speed and cost matter more than peak performance. Test 2-3 candidates with your actual prompts in Evvl to see the differences firsthand.
Can I compare Claude models with GPT or Gemini?
Yes. Evvl supports OpenAI, Anthropic, Google, OpenRouter, Ollama, and LM Studio. You can compare any combination of models across providers in a single evaluation.
Is my API key safe?
Your API key is stored locally in your browser and never saved on our servers. In the web app, Anthropic calls are proxied due to CORS restrictions. Your key is used for the request and immediately discarded. The desktop app calls Anthropic directly with no intermediary.
Start evaluating Claude models
Compare Claude Opus, Sonnet, Haiku, and more side by side. No login required.
Try Evvl Free