Claude Opus 5.5 vs GPT-6 Astra: cost comparison

For a typical chatbot reply, Claude Opus 5.5 is 1.9× cheaper than GPT-6 Astra ($18.20 vs $35.00 per 1,000 replies, including Claude's ~30% higher token count).

Claude Opus 5.5 Anthropic

$4.00input /1M

$0.20cached /1M

$20.00output /1M

Uses Anthropic's newer tokenizer, which produces about 30% more tokens for the same text than Claude Sonnet 4.6 and earlier.
Batch processing: 50% off input and output ($2.00 / $10.00 per 1M tokens).

GPT-6 Astra OpenAI

$10.00input /1M

$1.00cached /1M

$50.00output /1M

Prompts over 272,000 tokens are billed at $20.00 input / $2.00 cached / $75.00 output per 1M tokens for the whole request.
Batch processing: 50% off input and output ($5.00 / $25.00 per 1M tokens).

Cost per 1,000 requests

Workload	Claude Opus 5.5	GPT-6 Astra	Difference
Chatbot reply1,500 input / 400 output tokens	$18.20	$35.00	1.9×
RAG answer8,000 input / 600 output tokens	$57.20	$110.00	1.9×
Agent step30,000 input (80% cached) / 800 output	$58.24	$124.00	2.1×
Summarize a long report60,000 input / 1,200 output tokens	$343.20	$660.00	1.9×
Classify a ticket400 input / 10 output tokens	$2.34	$4.50	1.9×

Standard pricing, no batch discount. Claude 4.7+ costs include its ~30% higher token count for the same text. Price is only one factor; quality, speed, context length and rate limits matter too, so test both on your own prompts.

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