Claude 4.5 Sonnet vs Claude 4.5 Opus
Compare pricing, context windows, and strengths for Claude 4.5 Sonnet by Anthropic and Claude 4.5 Opus by Anthropic - and see how to put either to work in Appaca.
Claude 4.5 Sonnet
A frontier-level hybrid-reasoning model excelling at coding, long-horizon tasks, computer use, and domain reasoning with top-tier alignment and reliability.
View Claude 4.5 SonnetClaude 4.5 Opus
Anthropic's November 2025 flagship model, combining maximum capability with practical performance for coding, agents, computer use, and enterprise workflows.
View Claude 4.5 OpusClaude 4.5 Sonnet vs Claude 4.5 Opus at a glance
Specs and pricing side by side, from the Appaca AI models directory.
| Spec | Claude 4.5 Sonnet | Claude 4.5 Opus |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Model type | Text | Text |
| Context window | 1M tokens | 200K tokens |
| Input price | $3 / 1M tokens | $5 / 1M tokens |
| Output price | $15 / 1M tokens | $25 / 1M tokens |
| Status | Superseded by Claude 4.6 Sonnet | Superseded by Claude 4.6 Opus |
How Claude 4.5 Sonnet and Claude 4.5 Opus differ
What the numbers mean in practice when choosing between Claude 4.5 Sonnet and Claude 4.5 Opus.
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Claude 4.5 Sonnet is 40% cheaper on input tokens ($3 vs $5 per million), which adds up quickly in document-heavy workloads.
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Claude 4.5 Sonnet is 40% cheaper on output tokens ($15 vs $25 per million) - the bigger factor for tools that generate long documents.
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Claude 4.5 Sonnet's 1M tokens context window is roughly 5x larger than Claude 4.5 Opus's 200K tokens, so it can work across bigger codebases, contracts, or archives in one pass.
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Claude 4.5 Sonnet has been superseded by Claude 4.6 Sonnet - for new builds, consider the newer model first.
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Claude 4.5 Opus has been superseded by Claude 4.6 Opus - for new builds, consider the newer model first.
Strengths side by side
Where each model shines, according to benchmarks and provider positioning.
Claude 4.5 Sonnet
1. Best-in-class coding performance
- #1 on SWE-bench Verified (77.2% standard, 82.0% high-compute).
- Excels at debugging, architecture, and multi-file code generation.
- Maintains coherence for extremely long tasks (30+ hours).
2. State-of-the-art computer use & agents
- Leads OSWorld at 61.4%.
- Strongest model for agentic workflows, multi-step tool use, and real computer control.
- Powering Claude Code, the new Claude Agent SDK, and Chrome agent actions.
3. Advanced reasoning & math
- Large improvements across reasoning-heavy benchmarks (AIME, MMMLU, τ2-bench, Terminal-Bench).
- Deep multi-step reasoning with extended or interleaved thinking.
4. High alignment & safety
- Most aligned Claude model to date with reduced deception, hallucinations, sycophancy, and harmful compliance.
- Strong protections against prompt injection for agentic tasks (ASL-3 safeguards).
5. Domain-expert performance
- Notable gains in finance, law, medicine, and STEM tasks.
- Trusted by early customers for long-context legal analysis, multi-file engineering, security research, and red-teaming.
Claude 4.5 Opus
1. Maximum capability with more practical pricing
- Anthropic introduced Opus 4.5 as its most intelligent model, combining maximum capability with practical performance.
- It was positioned as the best model in the world for coding, agents, and computer use at launch, with pricing reduced to $5/M input and $25/M output.
2. Step-change gains for coding and advanced agent work
- Anthropic describes Opus 4.5 as state-of-the-art on real-world software engineering tests.
- It also improved everyday knowledge-work tasks like deep research, slides, and spreadsheets while staying strong on long-horizon agent workflows.
3. Better control over reasoning depth
- Opus 4.5 introduced the
effortparameter, letting developers trade off response thoroughness against token efficiency. - This made it easier to use one flagship model across both high-depth analysis and more cost-sensitive production workloads.
4. Stronger computer use and continuity
- Added enhanced computer use with a zoom action for inspecting detailed screen regions.
- Preserves prior thinking blocks across turns, helping the model maintain reasoning continuity in extended multi-step tasks.
Use Claude 4.5 Sonnet or Claude 4.5 Opus - or both
Appaca is the AI workspace for operators. Build internal tools and AI co-workers powered by Claude 4.5 Sonnet or Claude 4.5 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 and it builds a working app powered by Claude 4.5 Sonnet or Claude 4.5 Opus. No code, no API keys, no deployment.
Switch models without rebuilding
Start on Claude 4.5 Sonnet, test the same tool on Claude 4.5 Opus, and keep whichever performs better - 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 and it builds a working app powered by Claude 4.5 Sonnet or Claude 4.5 Opus - connected to the tools you already use.
Related comparisons
See how Claude 4.5 Sonnet and Claude 4.5 Opus stack up against other models in the directory.
FAQs
Claude 4.5 Sonnet is generally cheaper: $3 input / $15 output per million tokens, versus $5 / $25 for Claude 4.5 Opus. Actual cost depends on how many tokens your workload reads and writes.
Claude 4.5 Sonnet has the larger context window at 1M tokens, compared to 200K tokens for Claude 4.5 Opus. A larger window means the model can consider more text at once - useful for long contracts, codebases, or months of records.
It depends on the job. Compare the pricing, context window, and strengths above against your workload - and remember the choice isn't permanent. In Appaca you can build a tool on Claude 4.5 Sonnet, test the same tool on Claude 4.5 Opus, and switch at any time without rebuilding anything.
Yes. Appaca is a no-code AI workspace: describe the internal tool your team needs and the Appaca agent builds it as a working app powered by Claude 4.5 Sonnet, Claude 4.5 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 AI tools with Claude 4.5 Sonnet or Claude 4.5 Opus
Describe the 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.