Claude model comparison · updated October 8, 2026
Haiku 5.5 vs Opus 5.5
Claude Opus 5.5 is Anthropic's flagship for long-running agentic work; Claude Haiku 5.5 is its fastest and cheapest model. Both read 1M tokens and write up to 128K, so the real differences are quality, speed and price. Here is how far apart they are, and which one to use.
Choose Haiku 5.5
for speed and volume: chat, extraction, classification, routing and sub-agent jobs. It costs 1/40 of Opus 5.5 per token.
Choose Opus 5.5
for long, hard or high-stakes work: agentic coding, deep research and complex knowledge work. It leads on every benchmark the two launches share.
Or use both: let Opus 5.5 plan and review, and hand the high-volume steps to Haiku 5.5.
- cheaper per token on Haiku 5.5 (prompts up to 100K tokens)
- 40×
- points Opus 5.5 leads by on Terminal-Bench 4.0, the widest gap
- +27.2
- token context window on both models
- 1M
- Haiku 5.5's latency rating from Anthropic. Opus 5.5 is rated moderate
- Fastest
Specs side by side
Same context window, same output limit, same tokenizer and the same five effort levels. The differences are price, speed and how thinking works.
| Spec | Claude Haiku 5.5 | Claude Opus 5.5 |
|---|---|---|
| API model ID | claude-haiku-5-5 | claude-opus-5-5 |
| Released | October 7, 2026 | September 22, 2026 |
| Context window | 1M tokens | 1M tokens |
| Max output | 128K tokens (300K on the Batch API, beta) | 128K tokens (300K on the Batch API, beta) |
| Price per 1M tokens (input / output) | $0.10 / $0.50 for prompts up to 100K tokens; $0.50 / $2.50 above | $4 / $20 at any prompt length |
| Cache reads per 1M tokens | $0.01 (prompts up to 100K tokens) | $0.20 |
| Batch API per 1M tokens | $0.05 / $0.25 | $2 / $10 |
| Thinking | Adaptive, on by default; can be turned off | Adaptive, always on |
| Effort levels | low · medium · high · xhigh · max (default medium) | low · medium · high · xhigh · max (default medium) |
| Latency (Anthropic's rating) | Fastest | Moderate |
| Fast mode | Not available | $8 / $40 per 1M tokens, up to 2.5× faster output (Claude API) |
| Input → output | Text and images → text | Text and images → text |
| Knowledge cutoff | June 2026 | June 2026 |
| Built for | High-volume, latency-sensitive work: classification, routing, extraction, sub-agents | Long-running agentic coding and knowledge work |
Claude API list prices in US dollars. Both models use the same newer tokenizer, so a prompt is the same number of tokens on either.
Benchmarks: Opus 5.5 leads, but by how much?
The launch posts for the two models share four benchmarks. Opus 5.5 wins all four. The gap is narrowest on expert reasoning and graded coding patches, and widest on long, multi-step terminal work.
Per point of score, Haiku 5.5 is the bargain: on Humanity's Last Exam and FrontierCode it reaches about 85% of Opus 5.5's score at 1/40 of the per-token price. On Terminal-Bench 4.0, where the model has to carry out multi-step jobs in a command line, Opus 5.5 is in another class.
Token use differs by model and effort level, so the cheaper model per token is not always cheaper per finished task. For long, hard tasks, test both on your own work before you decide.
Scores from Anthropic's launch posts for Haiku 5.5 (Oct 7, 2026) and Opus 5.5 (Sep 22, 2026). Opus 5.5 ran at max effort, Terminal-Bench 4.0 at xhigh. Both posts also report OSWorld 2.1 and Chartography, but on different setups (offline subset vs partial credit; without vs with tools), so those are left out here.
Price: 40× apart per token
Because both models share a tokenizer, the per-token gap is the real gap. It narrows in two places: prompts over 100K tokens, where Haiku 5.5 moves to its higher rate card, and cache reads, which Opus 5.5 prices at only 5% of its input rate.
| Per 1M tokens | Haiku 5.5 · prompt ≤ 100K | Haiku 5.5 · prompt > 100K | Opus 5.5 | Opus ÷ Haiku |
|---|---|---|---|---|
| Input | $0.10 | $0.50 | $4 | 40× |
| Output | $0.50 | $2.50 | $20 | 40× |
| Cache write (5 min) | $0.125 | $0.625 | $5 | 40× |
| Cache read | $0.01 | $0.05 | $0.20 | 20× |
| Batch input | $0.05 | $0.25 | $2 | 40× |
| Batch output | $0.25 | $1.25 | $10 | 40× |
What typical jobs cost
1,000 chat replies
2,000 input + 500 output tokens each
- Haiku 5.5
- $0.45
- Opus 5.5
- $18.00
40× cheaper on Haiku 5.5
One long-document question
150K-token prompt + 2,000-token answer
- Haiku 5.5
- $0.08
- Opus 5.5
- $0.64
8× cheaper on Haiku 5.5
10,000 batch classifications
1,000 input + 200 output tokens each, Batch API
- Haiku 5.5
- $1.00
- Opus 5.5
- $40.00
40× cheaper on Haiku 5.5
List prices without caching. Output tokens include thinking, so the effort level you pick moves the real cost on both models.
Speed and thinking
Anthropic rates Haiku 5.5 as the fastest model in its lineup and Opus 5.5 as moderate. Artificial Analysis measured Haiku 5.5 at about 244 output tokens per second on Anthropic's API in October 2026, well above the 111 tokens per second median of the models it compares.
Opus 5.5 can be quicker in one case: Fast mode, a research preview on the Claude API with up to 2.5× faster output at $8 / $40 per million tokens. Anthropic says Opus in Fast mode outpaces Haiku 5.5 at standard speed, at 80× Haiku's per-token price.
Both models think adaptively, default to medium effort and offer the same five levels from low to max. The difference: Haiku 5.5 lets you switch thinking off (at high effort or below) for the snappiest replies, while Opus 5.5's thinking is always on and effort is the only dial. Lower effort means fewer thinking tokens, which is faster and cheaper on either model.
Which one should you use?
Choose Haiku 5.5 when…
- Requests are many, short and alike: classification, routing, extraction, tagging, summaries.
- Latency matters: live chat, customer support, in-product assistants.
- It works as a sub-agent: quick lookups, file reads and context compaction inside a larger Opus 5.5 or Sonnet 5.5 run.
- You automate a browser or desktop at volume. Haiku 5.5 scores 72.4% on OSWorld 2.1 (offline subset), up from 15.7% for Haiku 4.5.
- Prompts stay under 100K tokens, where its price is lowest.
Choose Opus 5.5 when…
- The task is long and autonomous: multi-step agentic coding, migrations, debugging across a codebase.
- Mistakes are expensive: legal, financial or research work where the best answer is worth paying for.
- You need deep reasoning or expert knowledge work. Opus 5.5 leads on Humanity's Last Exam and GDPval-AA.
- You send 100K+ token prompts on every call. Opus 5.5 charges one rate up to 1M tokens, so the gap shrinks to 8×.
- You want the strongest model short of Claude Fable 5.1, which costs 2.5× more again.
Use them together
Anthropic pitches Haiku 5.5 as the sub-agent inside Opus 5.5 and Sonnet 5.5 runs: the big model plans and reviews, Haiku 5.5 does the many small steps. Devin reports a FrontierCode score of 66.2 for a setup that pairs Opus 5.5 with Haiku 5.5 as its sidekick model, at lower cost and latency. In the API, Opus 5.5 can also read Haiku 5.5's thinking blocks, so a conversation can be handed up from Haiku to Opus without losing its reasoning.
In between: Sonnet 5.5
If Haiku 5.5 falls short and Opus 5.5 feels like overkill, Claude Sonnet 5.5 costs $2 / $10 per million tokens, half of Opus 5.5, and lands close to it on several of the benchmarks above.
Switching between them in the API
Swapping the model ID does most of the work, but a few request options behave differently.
| Request option | Claude Haiku 5.5 | Claude Opus 5.5 |
|---|---|---|
| Turning thinking off | Allowed at effort high or below | Rejected (400): lower the effort instead |
| Forcing a tool call (tool_choice any or tool) | Allowed; the call comes without thinking first | Rejected (400): use auto with a strict tool |
| Server-side fallback on refusal | Not available | Available (beta) |
| Fast mode | Not available | Research preview, Claude API only |
| Prompts over 100K tokens | Billed on the higher rate card | Same rate up to 1M tokens |
The same on both: non-default temperature, top_p and top_k return an error, assistant prefill is rejected, computer use goes through the new computer toolset, and both take up to 1M input and 128K output tokens.
Haiku 5.5 vs Opus 5.5: questions
Is Haiku 5.5 better than Opus 5.5?
No. Opus 5.5 scores higher on every benchmark the two launch posts share: by 8 to 27 points on the percentage tests and by 226 Elo on GDPval-AA. Haiku 5.5 wins on speed and price. Anthropic rates it its fastest model, and it costs 40× less per token.
How much cheaper is Haiku 5.5 than Opus 5.5?
40× per token for prompts up to 100K tokens: $0.10 / $0.50 versus $4 / $20 per million input / output tokens. Above 100K tokens Haiku 5.5 charges $0.50 / $2.50, so the gap narrows to 8×. Cache reads are 20× cheaper ($0.01 vs $0.20).
Do Haiku 5.5 and Opus 5.5 have the same context window?
Yes. Both read up to 1M tokens and write up to 128K tokens per response (300K on the Batch API with a beta header). Haiku 5.5 charges more for prompts over 100K tokens; Opus 5.5 charges the same at any length.
Which is faster, Haiku 5.5 or Opus 5.5?
Haiku 5.5. Anthropic rates it the fastest model in its lineup and Opus 5.5 as moderate. Opus 5.5's paid Fast mode is quicker still, but it costs $8 / $40 per million tokens.
Can Haiku 5.5 replace Opus 5.5 for coding?
For quick edits, lookups and sub-agent work, often yes. For long autonomous coding, no: Opus 5.5 scores 66.4% on Terminal-Bench 4.0 against 39.2% for Haiku 5.5, and Anthropic recommends Opus 5.5 or Sonnet 5.5 for complex agentic coding.
Where can I try Haiku 5.5 for free?
Right here. Haiku55 lets you chat with Claude Haiku 5.5 free without signing up, with web search and link reading built in. Opus 5.5 is available through Anthropic's Claude apps and the Claude API.
Keep reading
- Haiku 5.5 pricingThe full rate card, the 100K-token rule and a cost calculator.
- Haiku 5.5 benchmarksEvery published score next to Haiku 4.5, Sonnet 5.5 and GPT-6 Luna.
- Haiku 5.5 vs Haiku 4.5What changed in the new Haiku, including API breaking changes.
- Chat with Haiku 5.5 freeNo sign-up needed. Web search and link reading built in.
Try Claude Haiku 5.5 free, right now
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Start chatting freeSources
- Anthropic — Introducing Claude Haiku 5.5
- Anthropic — Introducing Claude Opus 5.5
- Claude Docs — Pricing
- Claude Docs — Claude Haiku 5.5 overview
- Claude Docs — Claude Opus 5.5 overview
- Anthropic — Claude Haiku (availability, customer results)
- Artificial Analysis — Claude Haiku 5.5
Haiku55 is an independent service and is not affiliated with Anthropic. Prices and scores are as published by Anthropic and the testers named above, checked on October 8, 2026; see the sources for later changes.