Claude 5 Sonnet vs Claude 4.8 Opus
Compare pricing, context windows, and strengths for Claude 5 Sonnet by Anthropic and Claude 4.8 Opus by Anthropic - and see how to put either to work in Appaca.
Claude 5 Sonnet
Anthropic's most agentic Sonnet yet, closing much of the gap to Opus 4.8 on reasoning, coding, and tool use while staying at Sonnet's speed and price.
View Claude 5 SonnetClaude 4.8 Opus
Anthropic's flagship model for coding and agents, building on Opus 4.7 with stronger reliability, a cheaper fast mode, and gains across coding, computer use, and professional work.
View Claude 4.8 OpusClaude 5 Sonnet vs Claude 4.8 Opus at a glance
Specs and pricing side by side, from the Appaca AI models directory.
| Spec | Claude 5 Sonnet | Claude 4.8 Opus |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Model type | Text | Text |
| Context window | 1M tokens | 1M tokens |
| Input price | $3 / 1M tokens | $5 / 1M tokens |
| Output price | $15 / 1M tokens | $25 / 1M tokens |
| Status | Current | Current |
How Claude 5 Sonnet and Claude 4.8 Opus differ
What the numbers mean in practice when choosing between Claude 5 Sonnet and Claude 4.8 Opus.
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Claude 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 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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Both models offer the same 1M tokens context window.
Strengths side by side
Where each model shines, according to benchmarks and provider positioning.
Claude 5 Sonnet
1. Anthropic's most agentic Sonnet yet
- A substantial upgrade over Sonnet 4.6 on reasoning, tool use, coding, and knowledge work - narrows the gap to Opus 4.8 while staying at Sonnet pricing.
- Early partners describe it finishing multi-step jobs end to end where prior Sonnet models used to stall halfway.
2. Clear benchmark gains over Sonnet 4.6
- 63.2% on SWE-bench Pro (vs 58.1%), 80.4% on Terminal-Bench 2.1 (vs 67.0%), 81.2% on OSWorld-Verified (vs 78.5%), and 57.4% on Humanity's Last Exam with tools (vs 46.8%).
- On the GDPval-AA v2 knowledge-work benchmark it edges past Opus 4.8 (1,618 vs 1,615).
3. Near-Opus performance at a fraction of the price
- Priced at $3/M input and $15/M output - 40% cheaper than Opus 4.8's $5/$25 - with introductory pricing of $2/$10 through Aug 31, 2026 during the rollout.
- Supports
low,medium,high, andxhigheffort levels, covering a wider cost-performance range than Sonnet 4.6 and matching Opus 4.8 on some tasks at higher effort.
4. Long-context, long-horizon reliability
- Full 1M token context window with up to 128K output tokens.
- Adaptive thinking automatically decides how long to reason; better self-correction, fewer tool errors, and steadier follow-through across long agent sessions in Claude Code and Cowork.
5. Safer and more honest than its predecessor
- Lower rates of hallucination, sycophancy, and misaligned behavior than Sonnet 4.6 on Anthropic's automated safety audits.
- Deliberately limited cyber capability compared with Opus-class models, shipped with cyber safeguards enabled by default.
6. Updated tokenizer
- Uses a new tokenizer (shared with the Opus 4.7/4.8 line) that can map the same text to up to 1.35x more tokens than Sonnet 4.6 - introductory pricing is set so the switch is roughly cost-neutral.
Claude 4.8 Opus
1. Modest but tangible gains across the board
- 69.2% on SWE-bench Pro (+4.9 points over Opus 4.7's 64.3%), 88.6% on SWE-bench Verified, and a 1,890 Elo on GDPval-AA - about 121 Elo ahead of GPT-5.5.
- Anthropic frames it as an incremental refinement of Opus 4.7 rather than a step-change release.
2. The most reliable agent model Anthropic has shipped
- The only model to complete every case end-to-end on Anthropic's internal Super-Agent benchmark, beating prior Opus models and GPT-5.5 at parity on cost.
- Leads CursorBench across every effort level with more efficient tool calling - fewer steps for the same intelligence.
- 84% on Online-Mind2Web and stronger OSWorld-Verified scores make it the strongest computer-use and browser-agent model Anthropic has tested.
3. New highs for professional and legal work
- Highest score ever recorded on Anthropic's Legal Agent Benchmark, and the first model to break 10% on its all-pass standard.
- Roughly a 4x improvement in honesty and calibrated uncertainty versus Opus 4.7 on Anthropic's evaluations.
4. Cheaper, faster controls
- Standard pricing holds at $5/M input and $25/M output, unchanged from Opus 4.7.
- Fast mode now runs at 2.5x speed for $10/M input and $50/M output - about a third of what fast mode cost on prior Opus releases.
- A new effort dial gives finer control over how hard the model works before answering.
5. Long-horizon agent workflows
- 1M token context window in beta and up to 128K output tokens.
- Introduces Dynamic Workflows (research preview) in Claude Code - Opus can write its own orchestration script and run up to 16 concurrent / 1,000 total subagents in a single session.
Use Claude 5 Sonnet or Claude 4.8 Opus - or both
Appaca is the AI workspace for operators. Build internal tools and AI co-workers powered by Claude 5 Sonnet or Claude 4.8 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 5 Sonnet or Claude 4.8 Opus. No code, no API keys, no deployment.
Switch models without rebuilding
Start on Claude 5 Sonnet, test the same tool on Claude 4.8 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 5 Sonnet or Claude 4.8 Opus - connected to the tools you already use.
Related comparisons
See how Claude 5 Sonnet and Claude 4.8 Opus stack up against other models in the directory.
FAQs
Claude 5 Sonnet is generally cheaper: $3 input / $15 output per million tokens, versus $5 / $25 for Claude 4.8 Opus. Actual cost depends on how many tokens your workload reads and writes.
They are equal: both Claude 5 Sonnet and Claude 4.8 Opus support a 1M tokens context window.
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 5 Sonnet, test the same tool on Claude 4.8 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 5 Sonnet, Claude 4.8 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 5 Sonnet or Claude 4.8 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.