// head_to_head
Claude Opus 5.5 vs GPT-6 Astra
Published LiveBench scores across all seven categories, live list pricing, context windows, and the measured cost of a point of capability — for both models, side by side.
Effectively the same quality — Claude Opus 5.5 is the cheaper way to get it.
The two are within 0.5 points overall, which is inside the range that effort settings alone move a LiveBench score, so treat them as quality-equivalent. Claude Opus 5.5 lists 2.5× cheaper per blended million tokens. When quality ties, cost is the whole decision.
anthropic
Claude Opus 5.5
- Blended / 1M
- $8.00
- Context
- 1M
- Released
- Sep 22, 2026
- Overall score
- 85.1
openai
GPT-6 Astra
- Blended / 1M
- $20.00
- Context
- 1.1M
- Released
- Sep 4, 2026
- Overall score
- 85.6
Specs and pricing
| Metric | Claude Opus 5.5 | GPT-6 Astra |
|---|---|---|
| LiveBench overall Weighted mean of the seven LiveBench category scores, 0–100. Higher is better. | 85.1 | 85.6 |
| Cost per point Measured benchmark spend divided by overall score — dollars per point of capability. | $0.0482 | $0.0483 |
| Blended price / 1M 3:1 input:output mix, the usual shape of production traffic. | $8.00win | $20.00 |
| Input price / 1M | $4.00win | $10.00 |
| Output price / 1M | $20.00win | $50.00 |
| Cached input / 1M Price of an input token served from the prompt cache, where the provider publishes one. | $0.200win | $1.00 |
| Context window | 1M | 1.1M |
| Max output tokens | 128K | 128K |
Benchmarks by category
An overall score averages away the thing you probably care about. These are the seven LiveBench categories scored separately — Claude Opus 5.5 on top, GPT-6 Astra below, both out of 100.
What each one costs to run
Per-token prices are hard to feel. These are monthly list costs for both models across five workload shapes, using each provider's published cached-input rate where there is one.
| Workload | Claude Opus 5.5 | GPT-6 Astra |
|---|---|---|
| Support chatbot 1.2K in / 400 out × 200K requests | $2,286/mo | $5,752/mo |
| RAG assistant 8K in / 600 out × 100K requests | $2,880/mo | $7,400/mo |
| Coding agent 40K in / 4K out × 20K requests | $2,672/mo | $6,960/mo |
| Document extraction 20K in / 1.5K out × 50K requests | $5,310/mo | $13,300/mo |
| Bulk classification 500 in / 20 out × 5M requests | $10,100/mo | $25,500/mo |
Which should you pick?
The workload is coding or agentic work
GPT-6 Astra
Leads on long-horizon agentic — 77.5 against 72.8.
You are cost-constrained
Claude Opus 5.5
Cheaper on blended list price at $8.00 per million tokens.
Claude Opus 5.5 vs GPT-6 Astra FAQ
Which is better, Claude Opus 5.5 or GPT-6 Astra?
Effectively the same quality — Claude Opus 5.5 is the cheaper way to get it. The two are within 0.5 points overall, which is inside the range that effort settings alone move a LiveBench score, so treat them as quality-equivalent. Claude Opus 5.5 lists 2.5× cheaper per blended million tokens. When quality ties, cost is the whole decision.
Is Claude Opus 5.5 cheaper than GPT-6 Astra?
Claude Opus 5.5 is cheaper. On a 3:1 input:output blend, Claude Opus 5.5 lists at $8.00 per million tokens and GPT-6 Astra at $20.00 — Claude Opus 5.5 is 2.5× cheaper. Input and output are priced separately — Claude Opus 5.5 charges $4.00 in and $20.00 out, GPT-6 Astra charges $10.00 and $50.00 — so the model that looks cheaper flips depending on how output-heavy your workload is.
Claude Opus 5.5 vs GPT-6 Astra: which scores higher on benchmarks?
Claude Opus 5.5 scores 85.1 and GPT-6 Astra scores 85.6 overall on LiveBench, the weighted mean of its seven categories. That gap is inside the range that effort settings alone move a score, so treat them as equivalent on published quality. Category scores differ from the overall figure — a model can lead on reasoning and trail on coding, which the per-category table above breaks out.
Which gives better value for money, Claude Opus 5.5 or GPT-6 Astra?
They are close. Claude Opus 5.5 costs $0.0482 per point of overall capability and GPT-6 Astra costs $0.0483, a difference small enough that workload shape will matter more than the rate.
Does Claude Opus 5.5 or GPT-6 Astra have a bigger context window?
They are effectively the same — 1M for Claude Opus 5.5 and 1.1M for GPT-6 Astra.
Do Claude Opus 5.5 and GPT-6 Astra support prompt caching?
Both publish a cached-input rate: $0.200 per million for Claude Opus 5.5 and $1.00 for GPT-6 Astra, against full input rates of $4.00 and $10.00. On a workload with a long stable prefix — a system prompt, a tool schema, a retrieved corpus — that changes the economics more than the headline price does.
Related comparisons
How these numbers are produced
- Price — provider list price from OpenRouter, refreshed every 15 minutes. “Blended” is a 3:1 input:output mix.
- Scores — LiveBench release 2026-10-25, using their own category map. Each model shows its strongest published run. A blank means “not evaluated”, never “bad”.
- Cost per point — the measured dollars LiveBench spent on the run, divided by the score it earned.
- “Win” — awarded only past a threshold: one full point on a benchmark score, 10% on a price, 25% on a context window. Anything tighter reports as a tie, because effort settings alone move a LiveBench score by more than that.
Published benchmarks rank models on someone else's tasks. Before committing, see LLM & agent evaluation for building an eval on your own.