Claude Opus 5.5 and Claude Sonnet 5.5 are the two tiers most teams evaluate first in Anthropic's current line-up. Anthropic's Models overview recommends starting with Opus 5.5 for most workloads and positions Sonnet 5.5 as the best combination of speed and intelligence.
Every figure comes from Anthropic's Models overview, re-read on 2026-11-02. It is vendor documentation, not an independent benchmark, and it does not cover privacy terms or consumer plan limits.
Key differences at a glance
- Price: $4 / $20 per million input/output tokens for Opus 5.5 against $2 / $10 for Sonnet 5.5.
- Latency label: Moderate against Fast.
- Same limits: 1M-token context window and 128K-token maximum synchronous output.
- Thinking: adaptive and always on for Opus 5.5; adaptive (and can be steered) for Sonnet 5.5. Default effort is medium for Opus, high for Sonnet.
- Same reliable knowledge cutoff: June 2026.
Specification comparison
| Feature | Claude Opus 5.5 | Claude Sonnet 5.5 |
|---|---|---|
| API ID | claude-opus-5-5 | claude-sonnet-5-5 |
| Positioning | Long-running agentic coding and knowledge work | Best combination of speed and intelligence |
| Latency | Moderate | Fast |
| Context window | 1M tokens | 1M tokens |
| Max output | 128K tokens | 128K tokens |
| Price per MTok (in / out) | $4 / $20 | $2 / $10 |
| Extended thinking | Adaptive (always on) | Adaptive |
| Default effort | medium | high |
| Reliable knowledge cutoff | Jun 2026 | Jun 2026 |
Shaded cells mean the cited sources did not state the value. We do not fill gaps from memory.
Positioning and capability
Anthropic describes Opus 5.5 as built for long-running agentic coding and knowledge work, and recommends it as the starting point for most workloads. Sonnet 5.5 is described as the best combination of speed and intelligence. Anthropic states that all current models support text and image input, text output, multilingual use, vision and tool use, so the difference is capability and speed rather than modality. Neither the page nor AYORAHUB provides benchmark scores; test both on representative tasks.
Cost and latency
Opus 5.5 lists at twice Sonnet 5.5's price on both input and output. Anthropic notes Batch API requests are 50% off and prompt-cache reads cost 5% of the base input price for both of these models, which can change the economics of repeated long prompts. Latency is labelled Moderate for Opus and Fast for Sonnet, relative to the current line-up; actual latency depends on prompt length, output length and thinking effort.
Thinking and effort controls
Both use adaptive thinking, where the model decides how much to reason, steered by an effort setting. Opus 5.5's thinking is always on and its default effort is medium; Sonnet 5.5 defaults to high effort. Anthropic notes that Sonnet 5.5 does not accept a fully disabled thinking mode but does accept turning off up-front thinking between tools. Effort is a lever for cost and latency, so a lower-effort Opus call and a higher-effort Sonnet call can be closer in practice than the list prices suggest.
Context, output and availability
Both list a 1M-token context window, roughly 555,000 words on the current tokenizer according to Anthropic, and 128K tokens of synchronous output, with up to 300K on the Message Batches API using a beta header. Anthropic lists identifiers for its own API, Amazon Bedrock, Google Cloud, Microsoft Foundry and Claude Platform on AWS, with retirement not sooner than September 22, 2027 (Opus 5.5) and September 28, 2027 (Sonnet 5.5).
Strengths and limitations
Claude Opus 5.5
Strengths
- Page recommends it for most workloads and long-running agentic coding.
Limitations
- Twice the price of Sonnet 5.5; moderate latency.
Claude Sonnet 5.5
Strengths
- Half the listed price and faster.
Limitations
- Page positions it below Opus for long-running agentic work.
Verified pricing
Opus 5.5: $4 / $20. Sonnet 5.5: $2 / $10. Prices are per million tokens (MTok) as listed on the cited page on the verification date; they can change.
Which should you choose?
- Long-running agentic coding: Claude Opus 5.5 — positioned for it on the cited page
- Cost-sensitive volume with strong quality: Claude Sonnet 5.5 — $2 / $10 per MTok and fast latency
Our verdict
Both models share context and output limits, so the choice is capability versus cost and latency. Test both on your own tasks; this page reports specs, not benchmark results.
Frequently asked questions
Is Claude Opus 5.5 better than Sonnet 5.5?
Anthropic positions Opus 5.5 for long-running agentic coding and knowledge work and recommends it for most workloads; Sonnet 5.5 is faster and half the price. No benchmark is cited here, so evaluate both on your own tasks.
Do they have the same context window?
Yes. Anthropic lists 1M tokens of context and 128K tokens of maximum synchronous output for both.
How much cheaper is Sonnet 5.5?
Half the price: $2 / $10 per million input/output tokens against $4 / $20 for Opus 5.5, as listed on 2026-11-02.
Does this page cover privacy or data retention?
No. Anthropic's Models overview does not cover data-handling terms. Check Anthropic's commercial terms and your platform's policies.
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How this was checked
Specifications compiled on 2026-11-02 from the sources below. The cited sources were re-opened and the key table values re-checked on 2026-11-02.
Anthropic Models overview re-read on 2026-11-02; all listed values matched.
Disclosure: AYORAHUB did not hands-on test these products or services. Nothing on this page is a lab measurement, benchmark or review score; analysis explains what the cited specifications mean in practice.
- All Anthropic figures come from the single Models overview page; availability on cloud platforms is not stated there.
- No benchmark data is included.
Sources
- Models overview — Anthropic Claude Platform Docs (manufacturer/official)
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