Which is cheaper, Claude Opus 5 and Claude Opus 5.5?

Claude Opus 5.5 has the lowest input price. Per 1M input tokens: Claude Opus 5 from $5.00 and Claude Opus 5.5 from $4.00.

Can I switch between Claude Opus 5 and Claude Opus 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-opus-5, anthropic/claude-opus-5.5).

Claude Opus 5 vs Claude Opus 5.5

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

Claude Opus 5 Anthropicanthropic/claude-opus-5

Claude Opus 5.5 Anthropicanthropic/claude-opus-5.5

Creator

Anthropic

Released

Jul 24, 2026

Sep 22, 2026

Context window

Max output

128K

Input / 1MLowest provider price

$5.00

$4.00

Output / 1MLowest provider price

$25.00

$20.00

Providers

IntelligenceArtificial Analysis index

48.1

57.6

CodingArtificial Analysis index

76.5

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LatencyMedian time to first token

30s

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ThroughputMedian tokens per second

<1 t/s

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Accepts

Text, Image, Files

Produces

Text

Tool calling

Yes

Structured output

Yes

Reasoning

Yes

Claude Opus 5 vs Claude Opus 5.5: summary

Claude Opus 5 and Claude Opus 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 Opus 5, from Anthropic, has a 1,000,000-token context window, costs from $5.00/1M input and $25.00/1M output tokens across 3 providers and scores 48.1 on the Artificial Analysis Intelligence Index.

Claude Opus 5.5, from Anthropic, has a 1,000,000-token context window, costs $4.00/1M input and $20.00/1M output tokens and scores 57.6 on the Artificial Analysis Intelligence Index.

Claude Opus 5.5 is the cheapest on input, 1.3× cheaper than the next model and Claude Opus 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-opus-5", messages=[...]) # or client.chat.completions.create(model="anthropic/claude-opus-5.5", messages=[...])

Full API docs

Frequently asked questions

More comparisons

Benchmark scores sourced from ArtificialAnalysis