Claude Sonnet 5.5 wins on price ($2 vs $4/1M input). Claude Opus 5.5 wins on coding (100 vs 98). For most workflows, Claude Sonnet 5.5 is the stronger default — near-opus 5.5 quality on scoped work at half the price.
The safest Claude Sonnet 5.5 vs Claude Opus 5.5 default, the cheaper option worth trying first, and the specialist pick — before you read the detail below.
Claude Sonnet 5.5 is the strongest answer here for Claude Sonnet 5.5 vs Claude Opus 5.5 — pick it when quality of output matters more than the $2.00/1M/1M input you pay for it.
Claude Sonnet 5.5 is the cheaper way in for Claude Sonnet 5.5 vs Claude Opus 5.5, at $2.00/1M/1M input against Claude Sonnet 5.5's $2.00/1M/1M.
Claude Opus 5.5 is the fastest of these for Claude Sonnet 5.5 vs Claude Opus 5.5 — worth it when latency is what the reader notices, not the last few points of reasoning depth.
Claude Opus 5.5 leads on coding with a score of 100 vs 98 for Claude Sonnet 5.5.
Claude Sonnet 5.5 is cheaper at $2/1M input tokens vs $4/1M for Claude Opus 5.5.
Claude Sonnet 5.5 is the stronger default for coding tasks.
Claude Sonnet 5.5 is the safer default: it is built for everyday feature work, bug fixing and polished documents at mid-tier pricing, which covers most of what people bring to this comparison.
Claude Opus 5.5 earns its place when your work is mostly agentic coding and long-running agents and knowledge work where Opus 5 was the bar, even though it loses the overall count here.
Both models serve different primary workflows — Claude Sonnet 5.5 for everyday feature work and bug fixing and polished documents at mid-tier pricing, Claude Opus 5.5 for agentic coding and long-running agents and knowledge work where Opus 5 was the bar — so running each where it has a clear edge often beats forcing one to do both.
Switch the scoring lens to see whether the Claude Sonnet 5.5 vs Claude Opus 5.5 answer changes when cost, speed, or long-document depth leads the decision.
Anthropic / Balanced / Oct 10, 2026
Near-Opus 5.5 quality on scoped work at half the price.
Ranks models by the broadest mix of coding, writing, research, and long-context usefulness.
The work is long, ambiguous and multi-step — Anthropic positions Opus 5.5 for exactly that — or you need the lowest possible price, where Haiku 5.5 costs a twentieth as much.
Where the Claude Sonnet 5.5 vs Claude Opus 5.5 recommendation shifts once you weigh price or latency differently.
Near-Opus 5.5 quality on scoped work at half the price.
Anthropic's new coding default — top SWE-bench Pro score at a lower price than Opus 5.
List prices and published scores — the numbers this page's pick is built from.
| Model | Input | Output | Est. month | Context | Speed | Coding | Writing | Research |
|---|---|---|---|---|---|---|---|---|
| Claude Sonnet 5.5Anthropic | $2.00/1M | $10.00/1M | $40 | 1M tokens | Fast | 98 | 98 | 95 |
| Claude Opus 5.5Anthropic | $4.00/1M | $20.00/1M | $80 | 1M tokens | Deliberate | 100 | 97 | 99 |
Scores out of 100 — how we evaluate models. “Est. month” is 10M in / 2M out at list price: a ceiling, no discounts.
Why each one is on the shortlist for Claude Sonnet 5.5 vs Claude Opus 5.5, what it is genuinely good at, and where we would steer you away from it.
Our pick for Claude Sonnet 5.5 vs Claude Opus 5.5. It scores 98/100 on the coding axis we weight this page by, and nothing else in this shortlist matches it on output quality.
Anthropic's September 28, 2026 Sonnet — built for well-scoped everyday work like features, bug fixes, documents, slides and spreadsheets, priced at $2/$10 and close to Opus 5.5 on most of Anthropic's launch rows.
The work is long, ambiguous and multi-step — Anthropic positions Opus 5.5 for exactly that — or you need the lowest possible price, where Haiku 5.5 costs a twentieth as much.
The model most people should default to in the Claude lineup. Sonnet 5.5 lands within a few points of Opus 5.5 on most of Anthropic's launch rows, beats it on Terminal-Bench 4.0, and costs half as much. Step up to Opus 5.5 only when the task is open-ended and long.
Full pricing, benchmark table and release notes on the Claude Sonnet 5.5 page.
Here for latency: it answers fastest of anything listed for Claude Sonnet 5.5 vs Claude Opus 5.5, at 100/100 on coding.
Anthropic's September 22, 2026 Opus — a step up from Opus 5 on agentic coding, long-running agent work and vision, at a lower $4/$20 list price and with fewer tokens spent per finished task.
Your tasks are well-scoped and latency-sensitive — Sonnet 5.5 is half the price and Anthropic says it is the fastest Sonnet yet.
The new premium coding default from Anthropic. Opus 5.5 posts the highest SWE-bench Pro figure in any launch table we track and costs less than Opus 5 did. Fable 5.1 still makes sense for the hardest open-ended research at $10/$50; for almost everything else Opus 5.5 is the better buy, and Sonnet 5.5 at half the price is close behind on well-scoped work.
Full pricing, benchmark table and release notes on the Claude Opus 5.5 page.
UseRightAI recommendations are based on practical decision factors people actually feel in day-to-day use.
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Claude Sonnet 5.5 wins on more of the categories we score — coding, writing, research — so it is the better default of the two. Claude Opus 5.5 is the better pick when your work is mostly agentic coding and long-running agents and knowledge work where Opus 5 was the bar. Neither is universally "better": Claude Sonnet 5.5 is aimed at everyday feature work and bug fixing and polished documents at mid-tier pricing, Claude Opus 5.5 at agentic coding and long-running agents and knowledge work where Opus 5 was the bar.
Claude Sonnet 5.5 is cheaper at $2/1M input and $10/1M output. Claude Opus 5.5 costs $4/1M input and $20/1M output.
Both Claude Sonnet 5.5 and Claude Opus 5.5 have the same 1M context window.
Claude Opus 5.5 is better for coding with a score of 100 vs Claude Sonnet 5.5's 98 (out of 100). Claude Opus 5.5 is the overall coding leader in this directory at 100/100.
Claude Sonnet 5.5 is faster with a fast speed rating (score: 4) vs Claude Opus 5.5's deliberate rating (score: 2). Speed matters most for interactive and high-throughput work; for batch jobs the Claude Opus 5.5 latency penalty is usually invisible.
Anthropic itself says Opus 5.5 is better on loosely defined tasks that need longer reasoning. Trails Opus 5.5 on Humanity's Last Exam (64.5% vs 67.7%). Avoid it if the work is long, ambiguous and multi-step — Anthropic positions Opus 5.5 for exactly that — or you need the lowest possible price, where Haiku 5.5 costs a twentieth as much. That is the main case for looking at Claude Opus 5.5 instead.
Not ahead everywhere: Anthropic's own table has Opus 5 higher on Toolathlon Verified (80.6% vs 77.8%). Fast mode doubles the price to $8/$40. Terminal-Bench 4.0 differs by effort setting (66.4% at xhigh, 64.8% at max), so single-digit gaps against rivals are directional. Avoid it if your tasks are well-scoped and latency-sensitive — Sonnet 5.5 is half the price and Anthropic says it is the fastest Sonnet yet. Against Claude Sonnet 5.5 specifically, the gap shows up most on coding (98 vs 100).
Take a moderate workload of 10M input and 2M output tokens a month. Claude Sonnet 5.5 runs $40.00 (at $2/1M in and $10/1M out); Claude Opus 5.5 runs $80.00 (at $4/1M in and $20/1M out). That is a $40.00/month difference — Claude Sonnet 5.5 is the cheaper of the two at this volume, and the gap scales linearly as you send more. Output tokens dominate the bill on both, so prompt length matters far less than response length.
Yes, and for most teams that beats picking one. A common split is Claude Sonnet 5.5 for everyday feature work and bug fixing and polished documents at mid-tier pricing, with Claude Opus 5.5 handling agentic coding and long-running agents and knowledge work where Opus 5 was the bar. Since Claude Sonnet 5.5 is both the stronger and the cheaper option here, a split mainly makes sense if Claude Opus 5.5 covers a capability you specifically need.