Which is cheaper, Claude Haiku 5.5 and Claude Sonnet 5.5?

Claude Haiku 5.5 has the lowest input price. Per 1M input tokens: Claude Haiku 5.5 from $0.10 and Claude Sonnet 5.5 from $2.00.

Can I switch between Claude Haiku 5.5 and Claude Sonnet 5.5 without changing my code?

Yes. All of them are served through FastRouter's OpenAI-compatible API, so switching is a change of the model parameter (anthropic/claude-haiku-5.5, anthropic/claude-sonnet-5.5).

Claude Haiku 5.5 vs Claude Sonnet 5.5

Side-by-side pricing per provider, context window, benchmark scores and speed, all on one OpenAI-compatible API.

Claude Haiku 5.5 Anthropicanthropic/claude-haiku-5.5

Claude Sonnet 5.5 Anthropicanthropic/claude-sonnet-5.5

Creator

Anthropic

Released

Oct 7, 2026

Sep 28, 2026

Context window

Max output

128K

Input / 1MLowest provider price

$0.10

$2.00

Output / 1MLowest provider price

$0.50

$10.00

Providers

IntelligenceArtificial Analysis index

41.2

56.0

Accepts

Image, Text

Text, Image

Produces

Text

Tool calling

Yes

Structured output

Yes

Reasoning

Yes

Claude Haiku 5.5 vs Claude Sonnet 5.5: summary

Claude Haiku 5.5 and Claude Sonnet 5.5 are both available through FastRouter's OpenAI-compatible API, so switching between them is a change of model id, not a new integration.

Claude Haiku 5.5, from Anthropic, has a 1,000,000-token context window, costs $0.10/1M input and $0.50/1M output tokens and scores 41.2 on the Artificial Analysis Intelligence Index.

Claude Sonnet 5.5, from Anthropic, has a 1,000,000-token context window, costs $2.00/1M input and $10.00/1M output tokens and scores 56.0 on the Artificial Analysis Intelligence Index.

Claude Haiku 5.5 is the cheapest on input, 20× cheaper than the next model and Claude Sonnet 5.5 scores highest for intelligence.

Switch with one line

client = OpenAI(base_url="https://api.fastrouter.ai/api/v1", api_key="<FASTROUTER_API_KEY>") client.chat.completions.create(model="anthropic/claude-haiku-5.5", messages=[...]) # or client.chat.completions.create(model="anthropic/claude-sonnet-5.5", messages=[...])

Full API docs

Frequently asked questions

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Benchmark scores sourced from ArtificialAnalysis