Claude 4 Sonnet vs Claude 4 Opus for Research
Compare Claude 4 Sonnet by Anthropic and Claude 4 Opus by Anthropic for research tasks - pricing, context windows, and strengths, and see how to put either to work in Appaca.
Claude 4 Sonnet
A balanced-hybrid reasoning model tuned for everyday assistant and high-volume tasks.
View Claude 4 SonnetClaude 4 Opus
The flagship model, focused on deep reasoning, large-scale coding and sustained multi-step agentic workflows.
View Claude 4 OpusClaude 4 Sonnet vs Claude 4 Opus at a glance
Specs and pricing side by side, from the Appaca AI models directory.
| Spec | Claude 4 Sonnet | Claude 4 Opus |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Model type | Text | Text |
| Context window | 1M tokens | 200K tokens |
| Input price | $3 / 1M tokens | $15 / 1M tokens |
| Output price | $15 / 1M tokens | $75 / 1M tokens |
| Status | Superseded by Claude 4.5 Sonnet | Superseded by Claude 4.1 Opus |
What matters for Research
Evaluation criteria and how Claude 4 Sonnet and Claude 4 Opus compare on what research tasks actually require.
Depth and accuracy of scientific reasoning
Ability to synthesise multi-document context
Citation awareness and factual grounding
Structured output for reports and papers
-
Claude 4 Sonnet is 80% cheaper on input tokens ($3 vs $15 per million), which adds up quickly on high-volume research workloads.
-
Claude 4 Sonnet is 80% cheaper on output tokens ($15 vs $75 per million) - the bigger factor for research tasks that generate long responses.
-
Claude 4 Sonnet's 1M tokens context window is roughly 5x larger than Claude 4 Opus's 200K tokens, so it can handle bigger inputs in a single research pass.
-
Claude 4 Sonnet has been superseded by Claude 4.5 Sonnet - for new research builds, consider the newer model first.
-
Claude 4 Opus has been superseded by Claude 4.1 Opus - for new research builds, consider the newer model first.
Strengths side by side
Where each model shines, according to benchmarks and provider positioning.
Claude 4 Sonnet
- Hybrid reasoning: supports both fast (“near-instant”) and extended thinking modes.
- Optimised for responsiveness, cost and high-volume production workloads.
- Strong coding performance relative to prior Sonnet versions (improved over Sonnet 3.7).
- Available even in free tiers (alongside paid plans).
- Better suited for general-purpose use and agents where speed + cost-efficiency matter.
Claude 4 Opus
- Highest capability in the family: described as “our most powerful model yet” by Anthropic.
- Exceptional at long-running tasks requiring thousands of steps and sustained focus (e.g., continuous codebase work for hours).
- Excellent performance on benchmarks: e.g., SWE-bench 72.5 % and Terminal-bench 43.2 %.
- Designed for complex agentic workflows, deep reasoning, tool use, and large context windows.
- Placed under a higher safety classification (ASL-3) due to its frontier capability and risk profile.
Use Claude 4 Sonnet or Claude 4 Opus - or both
Appaca is the AI workspace for operators. Build internal research tools and AI co-workers powered by Claude 4 Sonnet or Claude 4 Opus - connected to your real data and ready for your whole team. No code, no deployment.
Describe it, and it's built
Tell the Appaca agent the internal tool you need for research and it builds a working app powered by Claude 4 Sonnet or Claude 4 Opus. No code, no API keys, no deployment.
Switch models without rebuilding
Start on Claude 4 Sonnet, test the same tool on Claude 4 Opus, and keep whichever performs better for your research workflow - the rest of your app stays exactly as it is.
Automated for the whole team
Schedule tools to run on autopilot - daily digests, weekly reports, real-time triggers - and share them with your whole team from one workspace.
Describe it, and it's built
Tell the Appaca agent what your team needs for research and it builds a working app powered by Claude 4 Sonnet or Claude 4 Opus - connected to the tools you already use.
Keep comparing for Research
More side-by-side model comparisons for research tasks.
FAQs
GPT-5.5 and Claude 4 Opus are the top research LLMs in 2026. GPT-5.5 produces well-structured research memos, literature summaries, and synthesis documents. Claude 4 Opus is preferred for tasks requiring careful reasoning about nuanced or contradictory evidence - it is more likely to flag uncertainty than state incorrect conclusions confidently. Gemini 2.5 Pro handles the longest source documents thanks to its 1M token context.
Claude 4 Sonnet is generally cheaper: $3 input / $15 output per million tokens, versus $15 / $75 for Claude 4 Opus. Actual cost depends on how many tokens your research workload reads and writes.
Claude 4 Sonnet has the larger context window at 1M tokens, compared to 200K tokens for Claude 4 Opus. For research tasks, a larger window means the model can consider more context at once without losing track.
Yes. Appaca is a no-code AI workspace: describe the internal tool your team needs for research and the Appaca agent builds it as a working app powered by Claude 4 Sonnet, Claude 4 Opus, or any other model in the directory - with a built-in database, team access, and integrations. No API keys to wire up and nothing to deploy.
Build Research tools with Claude 4 Sonnet or Claude 4 Opus
Describe the research tool your team needs and get a working app powered by the model you choose - with a built-in database, team access, and integrations. No code, no deployment.