Claude Opus 5.5 vs GPT-6 Astra
How does Claude Opus 5.5 (Anthropic) compare against GPT-6 Astra (OpenAI)? Side-by-side scores, capability ratings and pricing, plus a clear verdict.
🏆 Quick verdict
Claude Opus 5.5 comes out ahead with an AIVerso score of 99 vs 98 and an aggregate capability rating of 667 vs 665 across 7 categories. GPT-6 Astra still leads on Math & Logic, Knowledge and Long Context.
Overall winner
Claude Opus 5.5
by Anthropic
Score: 99/100
PriceFrom $20/mo (Pro)
Pricing details$4/$20 per 1M
Context window1M
Free tierNo
API accessYes
Open sourceNo
Headline factsFable-class coding for less · #1 SWE-bench Pro (89.9%) · #1 Terminal-Bench 4.0 (66.4%) · $4/$20 per 1M · 1M context
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GPT-6 Astra
by OpenAI
Score: 98/100
PriceFrom $20/mo (Plus)
Pricing details$10/$50 per 1M
Context window1M
Free tierNo
API accessYes
Open sourceNo
Headline factsOpenAI's "AGI-era" flagship · FrontierMath Tier 4 97.6% · Terminal-Bench 4.0 57.9% · 1M context
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📊 Capability ratings
AIVerso capability ratings (0–100) per category — an editorial summary informed by public benchmark results. Higher is better.
Category
Claude Opus 5.5
GPT-6 Astra
Math & Logice.g. AIME, MATH-500
96
97
Programminge.g. SWE-bench, LiveCodeBench
96
92
Reasoninge.g. GPQA, ARC
96
96
Knowledgee.g. MMLU-Pro
92
94
Long Contexte.g. MRCR, needle tests
95
96
Instruction Followinge.g. IFEval
95
95
Agent Capabilitye.g. Terminal-Bench, tool use
97
95
Why Claude Opus 5.5
Higher overall score (99 vs 98)
Lower API price ($4/$20 per 1M vs $10/$50 per 1M)
Leads on Programming (96 vs 92)
Leads on Agent Capability (97 vs 95)
Fable-class coding for less
#1 SWE-bench Pro (89.9%)
Why GPT-6 Astra
Leads on Math & Logic (97 vs 96)
Leads on Knowledge (94 vs 92)
Leads on Long Context (96 vs 95)
OpenAI's "AGI-era" flagship
FrontierMath Tier 4 97.6%
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❓ Frequently Asked Questions
Which is better: Claude Opus 5.5 or GPT-6 Astra?
Claude Opus 5.5 has the higher AIVerso score (99 vs 98). The better choice still depends on your use case — GPT-6 Astra leads on Math & Logic and Knowledge.
How much does Claude Opus 5.5 cost compared to GPT-6 Astra?
Claude Opus 5.5: From $20/mo (Pro) ($4/$20 per 1M). GPT-6 Astra: From $20/mo (Plus) ($10/$50 per 1M). Neither has a free tier.
What context window does each support?
Claude Opus 5.5: 1M tokens. GPT-6 Astra: 1M tokens. The context window determines how much text, code or chat history a model can process at once.
Are Claude Opus 5.5 and GPT-6 Astra open source?
Claude Opus 5.5 is a closed, proprietary model. GPT-6 Astra is a closed, proprietary model.
How we compare: Scores and capability ratings are based on public benchmarks and provider documentation — not on commission rates. Last updated: September 29, 2026.