Claude Opus 5.5 vs Claude Sonnet 5
The current Anthropic tier decision: Opus 5.5 costs twice Sonnet 5 for an identical million-token window, so the question is entirely about depth per turn.
What the numbers say
- Claude Sonnet 5 is about 2.0x cheaper on output tokens (120 vs 240 credits per 1M).
- Both take the same 1M-token context window.
- Claude Opus 5.5 is the newer release (September 2026 vs June 2026).
Derived from the live registry Zeplik routes and bills against. Credits: 1 credit = $0.10, computed from the raw provider rate with a 1.20x margin.
Side by side
Claude Opus 5.5
Anthropic
Claude Opus 5.5 is Anthropic's flagship model for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5.
- Provider
- Anthropic
- Context window
- 1M tokens
- Input price
- 48.0 credits / 1M tokens ($4.00 raw)
- Output price
- 240 credits / 1M tokens ($20.00 raw)
- Vision (image input)
- Yes
- Tool calling
- Yes
- Extended reasoning
- No
Best for
- Hard problems where answer quality matters more than cost: strategy, analysis, difficult writing
- Very long documents and codebases: a 1M-token window fits entire books or repositories in one conversation
- Working with images: screenshots, charts, photos and scanned documents alongside text
- Tool use and agents: reliably calls functions, so it can search, run skills and drive workflows
Claude Sonnet 5
Anthropic
Sonnet 5 is Anthropic's most capable Sonnet-class model, with frontier performance across coding, agents, and professional work.
- Provider
- Anthropic
- Context window
- 1M tokens
- Input price
- 24.0 credits / 1M tokens ($2.00 raw)
- Output price
- 120 credits / 1M tokens ($10.00 raw)
- Vision (image input)
- Yes
- Tool calling
- Yes
- Extended reasoning
- No
Best for
- Hard problems where answer quality matters more than cost: strategy, analysis, difficult writing
- Very long documents and codebases: a 1M-token window fits entire books or repositories in one conversation
- Working with images: screenshots, charts, photos and scanned documents alongside text
- Tool use and agents: reliably calls functions, so it can search, run skills and drive workflows
Try both on Zeplik
The honest answer to most model debates is to run your own prompt on both. Zeplik puts Claude Opus 5.5 and Claude Sonnet 5 in the same chat, so you can switch mid-conversation and compare answers on the work you actually do.
Frequently asked questions
- What is the difference between Claude Opus 5.5 and Claude Sonnet 5?
- Claude Sonnet 5 is about 2.0x cheaper on output tokens (120 vs 240 credits per 1M). Both take the same 1M-token context window. Claude Opus 5.5 is the newer release (September 2026 vs June 2026).
- Is Claude Opus 5.5 or Claude Sonnet 5 cheaper?
- Claude Sonnet 5 is cheaper: 120 credits per million output tokens against 240. 1 credit = $0.10, computed from the raw provider rate with a 1.20x margin.
- Which has the larger context window, Claude Opus 5.5 or Claude Sonnet 5?
- Neither: both take 1M tokens.
- Can I use both Claude Opus 5.5 and Claude Sonnet 5 on Zeplik?
- Yes. Zeplik is a multi-model chat, so both sit behind one account and you can switch between them mid-conversation to compare answers on your own prompt.
- Do Claude Opus 5.5 and Claude Sonnet 5 need a paid plan?
- Both need a paid plan (Plus or above). Usage is then billed in credits from your monthly allowance.
Related comparisons
- Claude Opus 5.5 vs Claude Opus 5The rare upgrade with nothing to weigh: Opus 5.5 is newer than Opus 5 and twenty percent cheaper on both input and output, at the same million-token window.
- GPT-6 Sol vs Claude Sonnet 5Priced identically at $2 in and $10 out, five percent apart on context: the closest like-for-like comparison in the catalogue, and a genuine toss-up on price alone.
- Claude Opus 5.5 vs GPT-6 AstraAnthropic's and OpenAI's deep-reasoning flagships, eighteen days apart -- and Astra asks two and a half times Opus 5.5's price for a window only five percent larger.
- Grok 4.7 vs Claude Sonnet 5Grok 4.7 answers for roughly half Sonnet 5's output price; Sonnet 5 answers with twice the context. The trade is unusually clean.
- Claude Opus 5.5 vs GPT-6 SolBoth shipped on the same day at adjacent tiers: whether Opus 5.5's depth is worth double GPT-6 Sol's price when their context windows are within five percent of each other.
- GPT-6 Astra vs Claude Sonnet 5Frontier against workhorse: whether GPT-6 Astra earns five times Sonnet 5's price on the work you actually send it.
Explore Zeplik
- 467 AI skillsReady-to-run expert methods that run on Claude Opus 5.5, Claude Sonnet 5 or any other model.
- 997 integrationsConnect Gmail, Slack, GitHub, Notion and hundreds more so the assistant can work in your apps.
- Simple pricingPlus, Pro and Max plans with a monthly credit allowance that works across every model.