By the toolist.ai editors. Researched from public sources, not hands-on tested by toolist.ai. Updated October 6, 2026; prices checked October 6, 2026.

Claude Opus 5 vs GPT-6 Astra

Verdict

For a new project, pick neither: Claude Opus 5 became a legacy model on September 22, and Claude Opus 5.5 is cheaper and stronger than both (see Claude Opus 5.5 vs GPT-6 Astra). Between these two, GPT-6 Astra wins seven of the nine benchmarks both have, including coding and science, while Claude Opus 5 costs half as much per token and leads on GDPval-AA knowledge work.

Verdict based on published prices, limits and benchmarks, not on our own tests.

Choose Claude Opus 5 if

  • Price matters: $5 and $25 per million tokens against Astra's $10 and $50
  • Your work is GDPval-style knowledge work (1724 Elo against 1542)
  • You already run on Opus 5 and need thinking switched off, which Opus 5 still allows

Choose GPT-6 Astra if

  • You need the stronger coder (59.1% against 49.0% on Terminal-Bench 4.0)
  • You work on science questions (63.3% against 28.6% on Terminal-Bench-Science; 96.1% against 93.2% on GPQA Diamond)
  • You want a fast first token: 5.5 seconds for Astra at medium effort against 21.4 for Opus 5 at its default high effort

Price

Input costs 2 times as much on GPT-6 Astra as on Claude Opus 5. Output costs 2 times as much on GPT-6 Astra as on Claude Opus 5.

Per million tokensClaude Opus 5GPT-6 Astra
Input$5 source$10 source
Cached input$0.50 source$1 source
Output$25 source$50 source

Claude Opus 5: Cache writes cost $6.25 per million tokens (5-minute cache) or $10 (1-hour cache). The Batch API costs half. There is no long-context surcharge. Fast mode costs $10 in and $50 out.

GPT-6 Astra: Prompts over 272,000 input tokens are billed at twice the input rate and 1.5 times the output rate for the whole request. Batch and Flex cost half; Fast mode costs double and Ultrafast six times.

Worked example: what a month costs

We priced three monthly workloads at the standard rates. The provider does not publish these figures.

WorkloadClaude Opus 5GPT-6 Astra
Support chatbot
100,000 replies, each 3,000 input and 400 output tokens, no caching (300M in, 40M out)		 $2,500$5,000
Document Q&A
5,000 questions over the same 60,000-token document set (90% cache hits), 800 output tokens each (300M in, 4M out)		 $385$770
Coding agent
200 tasks, each 1.5 million input tokens (90% cache hits) and 50,000 output tokens (300M in, 10M out)		 $535$1,070

Price your own workload

ModelCost a month
Claude Opus 5 $375
GPT-6 Astra $750

Standard API prices, no batch or priority discounts. Cached input is billed at the cache-read price; cache-write charges are not included. Reasoning models bill their thinking as output tokens.

Limits and release dates

Claude Opus 5GPT-6 Astra
ReleasedJuly 24, 2026 sourceSeptember 3, 2026 source
Context window1,000,000 tokens source1,050,000 tokens source
Maximum output128,000 tokens source128,000 tokens source
Knowledge cutoffMay 2026 sourceApril 30, 2026 source
Input and outputText and images in; text out sourceText and images in; text out source
API model nameclaude-opus-5gpt-6-astra

Benchmarks

Scores as published by the provider or measured by Artificial Analysis; higher is better. A dash means no score was published.

BenchmarkClaude Opus 5GPT-6 Astra
Artificial Analysis Intelligence Index
max effort		 50.8 source52.7 source
Intelligence Index at everyday effort 48.1 (high effort, the API default) source49.6 (medium effort; OpenAI publishes no default) source
Coding Agent Index 59.7 (Claude Code harness, max effort) source61.6 (Codex harness, max effort) source
Terminal-Bench 4.0
max effort		 49.0% source59.1% source
Humanity's Last Exam
max effort		 54.9% source54.7% source
GDPval-AA v2.1 (Elo)
max effort		 1724 source1542 source
SciCode
max effort		 56.4% source56.5% source
Terminal-Bench-Science 0.1
max effort		 28.6% source63.3% source
GPQA Diamond
max effort		 93.2% source96.1% source
Output speed 56.2 tokens/s (high effort, Anthropic API) source50.9 tokens/s (medium effort, OpenAI API) source

Benchmark and speed data from Artificial Analysis where linked.

Read more

Sources