Model vs model
Claude Opus 5.5 vs Claude Sonnet 5
Claude Opus 5.5 and Claude Sonnet 5 are both in llmwise. What each gets on every plan, what it reads, how it's served and what happens when its provider fails, from the catalog and the code that runs them.
Model prices and specs checked against OpenRouter's Claude Opus 5.5 page, OpenRouter's Claude Sonnet 5 page. Updated .
Short answer
Claude Sonnet 5 gets twice as many messages: up to 125 messages a month on Pro, against up to 62 messages a month for Claude Opus 5.5. Otherwise, only Claude Opus 5.5 can be passed to another model by its maker's safety system. In our test runs, Claude Opus 5.5 passed 49 of the 50 prompts both answered and Claude Sonnet 5 46; 5 prompts split them, most on summarization (5 to 3).
Claude Opus 5.5 vs Claude Sonnet 5, prompt by prompt
Every prompt Claude Opus 5.5 and Claude Sonnet 5 both answered, compared directly, their biggest differences first. One run each, through OpenRouter: a wait depends on the provider and the load that day, so a lead under 10% counts as close.
Of the 50 prompts both answered, both passed 45, only Claude Opus 5.5 passed 4, only Claude Sonnet 5 passed 1, and neither passed 0. Claude Opus 5.5 answered sooner on 6 of the 50 and Claude Sonnet 5 on 38; the rest were within 10% of each other. The 50 replies cost $0.5360 on Claude Opus 5.5 and $0.2030 on Claude Sonnet 5: 2.6× less on Claude Sonnet 5.
The 5 prompts only one of Claude Opus 5.5 and Claude Sonnet 5 passed
Announce a second bakery shop on LinkedIn (writing): Claude Opus 5.5 passed and Claude Sonnet 5 didn't. Claude Opus 5.5: Graded 5.0 of 5 on average (lowest 5). Claude Sonnet 5: Graded 3.5 of 5 on average (lowest 3).
Argue both sides of free buses (writing): Claude Sonnet 5 passed and Claude Opus 5.5 didn't. Claude Opus 5.5: Graded 4.7 of 5 on average (lowest 4); but a paragraph of 93 words, over the 90 allowed. Claude Sonnet 5: Graded 4.0 of 5 on average (lowest 4).
An article in three bullets (summarization): Claude Opus 5.5 passed and Claude Sonnet 5 didn't. Claude Opus 5.5: Graded 5.0 of 5 on average (lowest 5). Claude Sonnet 5: Graded 3.7 of 5 on average (lowest 3).
An email thread in one sentence (summarization): Claude Opus 5.5 passed and Claude Sonnet 5 didn't. Claude Opus 5.5: Graded 5.0 of 5 on average (lowest 5). Claude Sonnet 5: Graded 5.0 of 5 on average (lowest 5); but 32 words, over the 30 allowed.
Correlation between ad spend and sign-ups (data analysis): Claude Opus 5.5 passed and Claude Sonnet 5 didn't. Claude Opus 5.5: Final answer 0.97: right. Claude Sonnet 5: Final answer 0.99; expected 0.97.
Job by job, the widest gaps first
Summarization: Claude Opus 5.5 passed 5 of 5 and Claude Sonnet 5 3 of 5. Claude Sonnet 5 answered 1.3× sooner at the median, 3.7 s against 2.7 s. Claude Sonnet 5 cost 3.4× less, $0.0475 against $0.0140 for the 5 replies. Claude Opus 5.5's replies ran 19% longer, in tokens of reply, thinking not counted.
Data analysis: Claude Opus 5.5 passed 5 of 5 and Claude Sonnet 5 4 of 5. Claude Opus 5.5 answered 1.2× sooner at the median, 4.6 s against 5.3 s. Claude Sonnet 5 cost 1.9× less, $0.0654 against $0.0344 for the 5 replies. Claude Opus 5.5's replies ran 42% longer, in tokens of reply, thinking not counted.
Writing: Claude Opus 5.5 passed 4 of 5 and Claude Sonnet 5 4 of 5. Claude Sonnet 5 answered 1.8× sooner at the median, 8.2 s against 4.5 s. Claude Sonnet 5 cost 5.4× less, $0.0923 against $0.0171 for the 5 replies. Their replies ran to about the same length.
Translation: Claude Opus 5.5 passed 5 of 5 and Claude Sonnet 5 5 of 5. Claude Sonnet 5 answered 2.0× sooner at the median, 5.5 s against 2.8 s. Claude Sonnet 5 cost 3.6× less, $0.0540 against $0.0149 for the 5 replies. Claude Opus 5.5's replies ran 26% longer, in tokens of reply, thinking not counted.
RAG and answering from documents: Claude Opus 5.5 passed 5 of 5 and Claude Sonnet 5 5 of 5. Claude Sonnet 5 answered 1.6× sooner at the median, 2.9 s against 1.8 s. Claude Sonnet 5 cost 3.4× less, $0.0367 against $0.0109 for the 5 replies. Claude Opus 5.5's replies ran 101% longer, in tokens of reply, thinking not counted.
SQL: Claude Opus 5.5 passed 5 of 5 and Claude Sonnet 5 5 of 5. Claude Sonnet 5 answered 2.0× sooner at the median, 4.3 s against 2.2 s. Claude Sonnet 5 cost 3.2× less, $0.0459 against $0.0142 for the 5 replies. Claude Opus 5.5's replies ran 58% longer, in tokens of reply, thinking not counted.
Customer support: Claude Opus 5.5 passed 5 of 5 and Claude Sonnet 5 5 of 5. Claude Sonnet 5 answered 1.8× sooner at the median, 6.4 s against 3.5 s. Claude Sonnet 5 cost 3.0× less, $0.0540 against $0.0182 for the 5 replies. Their replies ran to about the same length.
Agents and tool use: Claude Opus 5.5 passed 5 of 5 and Claude Sonnet 5 5 of 5. Claude Sonnet 5 answered 1.6× sooner at the median, 3.1 s against 2.0 s. Claude Sonnet 5 cost 2.1× less, $0.0252 against $0.0121 for the 5 replies. Their replies ran to about the same length.
Math: Claude Opus 5.5 passed 5 of 5 and Claude Sonnet 5 5 of 5. Their median waits were close, 3.9 s against 3.9 s. Claude Sonnet 5 cost 1.8× less, $0.0298 against $0.0165 for the 5 replies. Their replies ran to about the same length.
Coding: Claude Opus 5.5 passed 5 of 5 and Claude Sonnet 5 5 of 5. Claude Sonnet 5 answered 2.7× sooner at the median, 7.2 s against 2.7 s. Claude Sonnet 5 cost 1.7× less, $0.0853 against $0.0508 for the 5 replies. Their replies ran to about the same length.
All 50 prompts: who passed, who answered sooner, who cost less
| Prompt | Result | Sooner | Cheaper |
|---|---|---|---|
| Turn a title into a URL slug | Both passed | Claude Sonnet 5, 1.3×took 3.1 s and 2.3 s | Claude Sonnet 5, 2.3×cost $0.0055 and $0.0024 |
| Parse a duration like “1h 30m” | Both passed | Claude Sonnet 5, 2.8×took 7.2 s and 2.6 s | Claude Sonnet 5, 3.1×cost $0.0112 and $0.0036 |
| Merge overlapping intervals | Both passed | Claude Sonnet 5, 1.4×took 3.7 s and 2.7 s | Claude Sonnet 5, 2.3×cost $0.0077 and $0.0034 |
| Evaluate an arithmetic expression, no eval | Both passed | Closetook 15.8 s and 16.9 s | Claude Sonnet 5, 1.5×cost $0.0336 and $0.0226 |
| Parse CSV with quoted fields | Both passed | Claude Opus 5.5, 1.3×took 11.9 s and 15.8 s | Claude Sonnet 5, 1.5×cost $0.0273 and $0.0187 |
| Announce a second bakery shop on LinkedIn | Only Claude Opus 5.5 | Claude Sonnet 5, 1.9×took 8.7 s and 4.6 s | Claude Sonnet 5, 4.7×cost $0.0175 and $0.0037 |
| Rewrite corporate jargon in plain words | Both passed | Claude Sonnet 5, 1.9×took 5.1 s and 2.7 s | Claude Sonnet 5, 3.5×cost $0.0078 and $0.0022 |
| Decline a meeting and offer two times | Both passed | Claude Sonnet 5, 1.5×took 4.1 s and 2.8 s | Claude Sonnet 5, 2.2×cost $0.0056 and $0.0026 |
| A product announcement with five rules | Both passed | Claude Sonnet 5, 1.8×took 8.2 s and 4.5 s | Claude Sonnet 5, 4.9×cost $0.0170 and $0.0035 |
| Argue both sides of free buses | Only Claude Sonnet 5 | Claude Sonnet 5, 3.4×took 22.5 s and 6.6 s | Claude Sonnet 5, 8.8×cost $0.0443 and $0.0050 |
| A discount, then sales tax | Both passed | Claude Sonnet 5, 1.4×took 2.7 s and 1.9 s | Claude Sonnet 5, 2.4×cost $0.0037 and $0.0015 |
| Pens at 3 for $4 | Both passed | Claude Opus 5.5, 1.2×took 5.3 s and 6.3 s | Claude Sonnet 5, 1.4×cost $0.0084 and $0.0061 |
| Compound interest over three years | Both passed | Closetook 3.7 s and 3.7 s | Claude Sonnet 5, 2.1×cost $0.0043 and $0.0021 |
| Four-digit numbers whose digits sum to 9 | Both passed | Closetook 4.7 s and 4.5 s | Claude Sonnet 5, 2.0×cost $0.0077 and $0.0039 |
| The highest of three dice is a 5 | Both passed | Closetook 3.9 s and 3.9 s | Claude Sonnet 5, 2.0×cost $0.0057 and $0.0028 |
| An article in three bullets | Only Claude Opus 5.5 | Claude Sonnet 5, 3.1×took 8.1 s and 2.6 s | Claude Sonnet 5, 6.3×cost $0.0171 and $0.0027 |
| An email thread in one sentence | Only Claude Opus 5.5 | Claude Sonnet 5, 1.1×took 2.6 s and 2.3 s | Claude Sonnet 5, 2.3×cost $0.0044 and $0.0019 |
| Decisions and action items from a meeting | Both passed | Claude Sonnet 5, 2.1×took 5.8 s and 2.8 s | Claude Sonnet 5, 3.5×cost $0.0118 and $0.0033 |
| A quarterly memo for the CEO | Both passed | Claude Sonnet 5, 1.2×took 3.5 s and 3.0 s | Claude Sonnet 5, 2.3×cost $0.0075 and $0.0033 |
| A study with a negative result | Both passed | Claude Sonnet 5, 1.3×took 3.7 s and 2.7 s | Claude Sonnet 5, 2.4×cost $0.0066 and $0.0028 |
| The region with the most revenue | Both passed | Claude Opus 5.5, 1.6×took 4.1 s and 6.4 s | Claude Sonnet 5, 2.1×cost $0.0087 and $0.0041 |
| Average order value in August | Both passed | Claude Sonnet 5, 1.1×took 4.4 s and 3.9 s | Claude Sonnet 5, 2.6×cost $0.0107 and $0.0041 |
| Revenue change from July to August | Both passed | Closetook 5.1 s and 5.3 s | Claude Sonnet 5, 1.9×cost $0.0120 and $0.0062 |
| A median, filtered two ways | Both passed | Closetook 4.6 s and 4.9 s | Claude Sonnet 5, 2.2×cost $0.0079 and $0.0036 |
| Correlation between ad spend and sign-ups | Only Claude Opus 5.5 | Claude Opus 5.5, 1.2×took 11.5 s and 13.8 s | Claude Sonnet 5, 1.6×cost $0.0261 and $0.0165 |
| A late order | Both passed | Claude Sonnet 5, 2.2×took 7.8 s and 3.5 s | Claude Sonnet 5, 3.2×cost $0.0114 and $0.0036 |
| A return inside the window | Both passed | Claude Sonnet 5, 1.5×took 4.4 s and 2.9 s | Claude Sonnet 5, 2.3×cost $0.0074 and $0.0032 |
| A frustrated customer | Both passed | Claude Sonnet 5, 1.5×took 6.4 s and 4.4 s | Claude Sonnet 5, 2.7×cost $0.0111 and $0.0041 |
| A refund request outside the window | Both passed | Claude Sonnet 5, 1.9×took 6.1 s and 3.2 s | Claude Sonnet 5, 3.4×cost $0.0106 and $0.0031 |
| A message with a planted instruction | Both passed | Claude Sonnet 5, 1.7×took 7.9 s and 4.6 s | Claude Sonnet 5, 3.3×cost $0.0136 and $0.0041 |
| A delivery message into Spanish | Both passed | Claude Sonnet 5, 1.2×took 3.2 s and 2.7 s | Claude Sonnet 5, 2.2×cost $0.0064 and $0.0029 |
| A product description into French | Both passed | Claude Sonnet 5, 2.3×took 5.8 s and 2.5 s | Claude Sonnet 5, 3.9×cost $0.0113 and $0.0029 |
| A meeting note into German | Both passed | Claude Sonnet 5, 2.0×took 5.5 s and 2.8 s | Claude Sonnet 5, 3.6×cost $0.0096 and $0.0027 |
| Idioms into natural Japanese | Both passed | Claude Opus 5.5, 1.1×took 3.6 s and 4.1 s | Claude Sonnet 5, 2.2×cost $0.0062 and $0.0028 |
| A lease clause into Brazilian Portuguese | Both passed | Claude Sonnet 5, 3.0×took 11.4 s and 3.8 s | Claude Sonnet 5, 5.7×cost $0.0204 and $0.0036 |
| Customers in one country | Both passed | Claude Sonnet 5, 1.4×took 2.5 s and 1.8 s | Claude Sonnet 5, 2.4×cost $0.0048 and $0.0020 |
| Count orders by status | Both passed | Claude Sonnet 5, 1.3×took 2.5 s and 2.0 s | Claude Sonnet 5, 2.5×cost $0.0049 and $0.0020 |
| Revenue by category | Both passed | Claude Sonnet 5, 1.2×took 4.3 s and 3.5 s | Claude Sonnet 5, 3.0×cost $0.0092 and $0.0031 |
| Every customer, even those without orders | Both passed | Claude Sonnet 5, 2.3×took 5.0 s and 2.2 s | Claude Sonnet 5, 3.1×cost $0.0094 and $0.0030 |
| Monthly revenue with a running total | Both passed | Claude Sonnet 5, 2.6×took 7.8 s and 3.0 s | Claude Sonnet 5, 4.2×cost $0.0176 and $0.0042 |
| A fact from one section | Both passed | Claude Sonnet 5, 1.5×took 2.5 s and 1.7 s | Claude Sonnet 5, 2.8×cost $0.0054 and $0.0019 |
| Core hours and start times | Both passed | Claude Sonnet 5, 1.3×took 2.6 s and 2.1 s | Claude Sonnet 5, 2.5×cost $0.0054 and $0.0022 |
| Two sections in one answer | Both passed | Claude Sonnet 5, 1.6×took 2.9 s and 1.8 s | Claude Sonnet 5, 2.4×cost $0.0053 and $0.0022 |
| A later amendment changes the answer | Both passed | Claude Sonnet 5, 3.6×took 7.7 s and 2.1 s | Claude Sonnet 5, 5.6×cost $0.0148 and $0.0026 |
| A question the handbook doesn't answer | Both passed | Claude Sonnet 5, 1.9×took 3.4 s and 1.8 s | Claude Sonnet 5, 3.0×cost $0.0057 and $0.0019 |
| Pick the tool and work out the date | Both passed | Claude Sonnet 5, 1.6×took 2.7 s and 1.7 s | Claude Sonnet 5, 2.3×cost $0.0041 and $0.0018 |
| Convert a currency | Both passed | Claude Sonnet 5, 1.4×took 2.8 s and 2.0 s | Claude Sonnet 5, 2.3×cost $0.0041 and $0.0018 |
| Book a meeting from a sentence | Both passed | Claude Sonnet 5, 1.3×took 7.2 s and 5.7 s | Claude Sonnet 5, 1.6×cost $0.0059 and $0.0037 |
| Search, but don't book | Both passed | Claude Sonnet 5, 1.7×took 3.1 s and 1.9 s | Claude Sonnet 5, 2.3×cost $0.0046 and $0.0020 |
| Two calls with a unit conversion | Both passed | Claude Opus 5.5, 1.1×took 3.4 s and 3.8 s | Claude Sonnet 5, 2.3×cost $0.0064 and $0.0028 |
Claude Opus 5.5 vs Claude Sonnet 5 in our test runs
Claude Opus 5.5 and Claude Sonnet 5 on the same prompts, job by job: how many replies passed their check.
Based on 100 of our test runs on , through OpenRouter with the app's own prompt and settings. Updated .
| Job | Claude Opus 5.5 | Claude Sonnet 5 |
|---|---|---|
| Coding | 5 of 5 | 5 of 5 |
| Writing | 4 of 5 | 4 of 5 |
| Math | 5 of 5 | 5 of 5 |
| Summarization | 5 of 5 | 3 of 5 |
| Data analysis | 5 of 5 | 4 of 5 |
| Customer support | 5 of 5 | 5 of 5 |
| Translation | 5 of 5 | 5 of 5 |
| SQL | 5 of 5 | 5 of 5 |
| RAG and answering from documents | 5 of 5 | 5 of 5 |
| Agents and tool use | 5 of 5 | 5 of 5 |
| All jobs | 49 of 50 · 1 message each · $0.0107 a reply | 46 of 50 · 1 message each · $0.0041 a reply |
The same prompts, sent to both through llmwise's own pipeline and checked the same way: five for each job. A bold count is the one that passed more. Messages: what each reply counted as on Pro. Cost: what OpenRouter charged us per reply, on average. Every prompt, and how it's scored.
Where they differed most, summarization: both replies to a prompt only one of them passed.
An everyday prompt: “An article in three bullets”, in full.
Claude Opus 5.5
Passed: Graded 5.0 of 5 on average (lowest 5).
- Aldmoor's six-month Market Street protected bike lane trial ended; council votes in November on keeping them. - Daily bike trips rose from 900 to 2,300, car traffic fell 14%, rush-hour drive times rose about a minute, and cyclist injuries dropped from nine to two. - Businesses were split; permanence would cost €1.1 million beyond the €410,000 installation.
727 tokens in, 674 out (539 of them reasoning) · 8.1 s · $0.0171 · 1 message on Pro · answered by anthropic/claude-opus-5.5 via Claude Platform on AWS ·
Claude Sonnet 5
Failed: Graded 3.7 of 5 on average (lowest 3).
- Aldmoor's 6-month trial bike lanes tripled cyclist trips (900→2,300/day), cut car traffic 14%, but added ~1 min to rush-hour drives. - Business impact mixed: 27 of 60 shops saw more customers, 19 fewer. - Injuries dropped (9→2); permanent install would cost €1.1M more.
725 tokens in, 125 out · 2.6 s · $0.0027 · 1 message on Pro · answered by anthropic/claude-sonnet-5 via Claude Platform on AWS ·
Claude Opus 5.5 and Claude Sonnet 5 on every plan
Whether the one-time free trial reaches each model, then each paid plan's messages on it.
| Plan | Price | Claude Opus 5.5 | Claude Sonnet 5 |
|---|---|---|---|
| Free | $0 | Not in the trial | Not in the trial |
| Plus | $10 a month | Up to 31 a month | Up to 62 a month |
| Pro | $20 a month | Up to 62 a month | Up to 125 a month |
| Max | $50 a month | Up to 200 a month | Up to 400 a month |
| Ultra | $100 a month | Up to 450 a month | Up to 900 a month |
| Studio | $200 a month | Up to 1,000 a month | Up to 2,000 a month |
Prices don't include tax, which is added where it applies and shown before you pay. A paid plan's month is one allowance shared by every model, so each monthly count is the most you get if all of it goes to that model. It renews each billing period; everyday models refill daily at 00:00 UTC. Long chats count more per reply. How pricing works.
Every limit is published. Paid plans also have a monthly fair-use limit on AI cost: Plus $3.75, Pro $7.50, Max $20, Ultra $42, Studio $85. Using every message on your plan at typical sizes stays under it; very large messages and heavy research use it faster. Every limit, explained.
What differs
Messages on Pro
Claude Sonnet 5 gets twice as many messages: up to 125 messages a month on Pro, against up to 62 messages a month for Claude Opus 5.5.
Context window
Both take up to 1M tokens of context. A chat in llmwise holds up to 200k tokens, which fits in either, so the difference shows only through each maker's own API.
Images and PDFs
Both read images. Both take a PDF as the whole file, pages and all.
On Free
Neither is in the free trial: both need a paid plan, from Plus.
Where messages go
Both are Claude models, served the same way. Sent to Anthropic directly.
Fact by fact
| Fact | Claude Opus 5.5 | Claude Sonnet 5 |
|---|---|---|
| Context window | 1M tokens | 1M tokens |
| Reads images | Yes | Yes |
| PDFs | Whole file | Whole file |
| Reasoning | Yes | Yes |
| API price (October 2026) | $4.00 in / $20.00 out per million tokens | $2.00 in / $10.00 out per million tokens |
| A typical message at API prices (4,000 tokens in, 700 out) | $0.0300 | $0.0150 |
| A $10 top-up adds | 50 messages | 100 messages |
| Where a message goes | Sent to Anthropic directly. | Sent to Anthropic directly. |
| If the provider fails | If Anthropic fails before the reply starts (an overload, a server error, a dropped connection), llmwise sends the same request to Claude Opus 5.5 through OpenRouter instead. | If Anthropic fails before the reply starts (an overload, a server error, a dropped connection), llmwise sends the same request to Claude Sonnet 5 through OpenRouter instead. |
| Anthropic's safety fallback | Anthropic's safety system can pass a Claude Opus 5.5 message to another Claude model. The reply then names the model that answered and says what you were charged for. | Doesn't apply |
Claude Opus 5.5 or Claude Sonnet 5?
From the facts above and our test runs: the rest is how their answers suit your work, which one chat can show you.
Pick Claude Sonnet 5: more messages for the money, up to 125 messages a month on Pro.
Each model's page, the families, and other pairs
Claude Opus 5.5 vs Claude Sonnet 5 is one pair of models. The page below covers the whole family.
- Claude Opus 5.5: price, limits and messages on every plan
- Claude Sonnet 5: price, limits and messages on every plan
- Claude playground: try Claude online
- Claude Fable 5.1 vs Claude Opus 5.5
- Claude Opus 5.5 vs Claude Sonnet 5.5
- Gemini 4 Argon vs Claude Opus 5.5
- Claude Sonnet 5.5 vs Claude Sonnet 5
- Claude Fable 5.1 vs Claude Sonnet 5
- Claude Sonnet 5 vs Claude Haiku 4.5
- Every model-vs-model page
Both are made by the same company, so they're served the same way.
Questions
Is Claude Opus 5.5 or Claude Sonnet 5 cheaper in llmwise?
Claude Sonnet 5 gets twice as many messages: up to 125 messages a month on Pro, against up to 62 messages a month for Claude Opus 5.5. Every paid plan's monthly allowance is shared by the models on it, so each count is the most you get if it all goes to that model.
Can I try Claude Opus 5.5 and Claude Sonnet 5 for free?
Neither is in the free trial of 5 messages: both need a paid plan, from Plus.
Which has the bigger context window, Claude Opus 5.5 or Claude Sonnet 5?
Neither: both take 1M tokens. A chat in llmwise holds up to 200k tokens, which fits in either, so the difference shows only through each maker's own API.
Can I use Claude Opus 5.5 and Claude Sonnet 5 in the same chat?
Yes. Pick Claude Opus 5.5 for one message and Claude Sonnet 5 for the next; the second sees the whole chat, including the first one's answer.
Which did better in your test runs, Claude Opus 5.5 or Claude Sonnet 5?
On the same 50 prompts, run on September 27, 2026, Claude Opus 5.5 passed 49 and Claude Sonnet 5 passed 46. The table on this page has each job, and every reply is published.
Claude, GPT, Gemini, DeepSeek, Grok, Kimi, GLM, and Mistral, in one chat.
See what a message costs before you send it. Free is 5 messages to try; sign in with an email link, no password or card.