Model comparison
Claude Opus 5.5 vs Gemini 4 Argon
Claude Opus 5.5 (Anthropic) and Gemini 4 Argon (Google) side by side: what each costs per million tokens through Rapid Router, how much context each takes, what each supports, and where independent benchmarks place them. Same API, same key; switching is a one-string change.
| Claude Opus 5.5 | Gemini 4 Argon | |
|---|---|---|
| Input price per 1M | $4.00 | $2.00 |
| Output price per 1M | $20.00 | $10.00 |
| Context window | 1M tokens | 1M tokens |
| Max output | 128K tokens | 33K tokens |
| Input types | text, image, pdf | text, image, video, audio, pdf |
| Capabilities | tools, JSON, vision, reasoning | tools, JSON, vision, audio, reasoning |
| Author | Anthropic | |
| LMArena Overall | 1516 | 1532 |
| LMArena Coding | 1545 | 1547 |
| LMArena Math | 1508 | 1536 |
| LMArena Creative writing | 1534 | 1527 |
| LMArena Instruction following | 1536 | 1536 |
| LMArena Hard prompts | 1535 | 1546 |
| LMArena Vision | 1321 | — |
| LMArena Web dev | 1811 | 1678 |
| GPQA Diamond | 90.6% | 96.4% |
| OTIS Mock AIME | 100.0% | 100.0% |
| SimpleQA Verified | 72.2% | 76.0% |
Scores from LMArena and Epoch AI, as published; a blank cell means not measured there.
What a month costs on each
| Workload | Claude Opus 5.5 | Gemini 4 Argon |
|---|---|---|
| Chatbot month (15M in, 4M out) | $140.00 | $70.00 |
| RAG month (40M in, 3M out) | $220.00 | $110.00 |
| Coding month (60M in, 10M out) | $440.00 | $220.00 |
On a typical 75/25 input-output mix, Gemini 4 Argon costs less (about 50% less than Claude Opus 5.5). Gemini 4 Argon takes the longer prompt at 1M tokens. Try your own numbers in the cost calculator.
Call either one
curl https://rapidrouter.ai/api/v1/chat/completions \
-H "Authorization: Bearer $RAPIDROUTER_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model": "anthropic/claude-opus-5-5", "messages": [{"role": "user", "content": "Hello"}]}'
# the other one: change the model string
-d '{"model": "google/gemini-4-argon", ...}'Common questions
Which is cheaper, Claude Opus 5.5 or Gemini 4 Argon?
Gemini 4 Argon is cheaper on a typical mix of 75% input and 25% output tokens, by about 50%. Through Rapid Router both are billed at the provider list price per million tokens.
Which has the larger context window?
Gemini 4 Argon, at 1M tokens. Claude Opus 5.5 offers 1M tokens.
Can I switch between Claude Opus 5.5 and Gemini 4 Argon without changing code?
Yes. Both are callable at https://rapidrouter.ai/api/v1 with the same OpenAI-compatible request; only the model string changes (anthropic/claude-opus-5-5 or google/gemini-4-argon).
How do I pay for Claude Opus 5.5 or Gemini 4 Argon?
Top up a Rapid Router balance by card in US dollars, and both models debit that balance per request.
More Claude models: Anthropic API pricing · More Gemini: Google API pricing