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Head to head

Claude Sonnet 5.5 vs Claude Opus 5.5

Sonnet 5.5 nearly matches Opus 5.5 on most measured work at a lower rate — it even beat Opus on Terminal-Bench 4.0. Pay for Opus when the work is long, open-ended and needs judgement throughout, which Anthropic says is where Opus is clearly stronger.

Try both on one keySee every model’s rate

Choose Claude Sonnet 5.5 if

  • Everyday coding and terminal work — 70.6% on Terminal-Bench 4.0 against Opus’s 66.4%.
  • Speed.
  • High volumes.
About Claude Sonnet 5.5

Choose Claude Opus 5.5 if

  • Long, open-ended work that needs sustained judgement.
  • Reviewing large codebases.
  • The most dependable answer on hard professional tasks.
About Claude Opus 5.5

Side by side

Claude Sonnet 5.5Claude Opus 5.5
Made byAnthropicAnthropic
ReleasedSeptember 2026September 2026
Input price, per 1M tokensS$2.68S$5.36
Output price, per 1M tokensS$13.39S$26.78
Cached input, per 1M tokensS$0.2678S$0.2678
Batch (about half price)YesYes
Context window1M tokens1M tokens
Longest answer128K tokens128K tokens
ReadsText, Images, PDFsText, Images, PDFs
Thinks before answeringYes, adjustableAlways on
Open weightsNoNo

Prices are Roar AI’s published rates, live from our price list. Specs are each lab’s own published figures. Prices are our published US dollar rates converted at S$1.30 to the dollar, our rate for October — the same rate your card is charged.

What a real job costs

Take 1,000 requests, each about 3,000 tokens in and 1,000 out — a long prompt and a page of answer.

Claude Sonnet 5.5S$21.42
Claude Opus 5.5S$42.85

Claude Sonnet 5.5 does the same job for 2.0× less. Models that think before answering spend extra output tokens doing it, so on hard prompts the real gap can be wider than the rates suggest.

Use both, switch any time

On Roar AI both are on the same key and the same monthly invoice, paid in your local currency. Trying the other one is a one-word change:

client.chat.completions.create(model="claude-sonnet-5-5", …)
client.chat.completions.create(model="claude-opus-5-5", …)

Send the same prompts to both for a day and compare the answers on your own work — that settles it faster than any benchmark. Read the docs.

More head-to-heads

Claude Sonnet 5.5 vs GPT-6.1 SolHead to headClaude Sonnet 5.5 vs Gemini 3.8 FlashHead to headGPT-5.3-Codex vs Claude Sonnet 5.5Head to headKimi K3 vs Claude Sonnet 5.5Head to headClaude Opus 5.5 vs GPT-6.1 SolHead to headGemini 3.1 Pro vs Claude Opus 5.5Head to head

Try both
on one key

Send the same prompts to each and compare the answers on your own work.

Get startedRead the docs