Claude Opus 5.5 vs GPT-6 Astra: API cost comparison

For a typical chatbot (1,500 input + 400 output tokens, 100,000 requests a month), Claude Opus 5.5 is 53% cheaper: $1,658 vs $3,500 for GPT-6 Astra. Paste your own prompt below to compare the exact cost of your workload.

0 characters0 words0 tokens (GPT o200k)

ModelInput tokensPrice / 1M (in → out)Per requestPer month
Claude Opus 5.5$4 → $20
GPT-6 Astra$10 → $50

≈ = estimated token count: only OpenAI publishes its tokenizer. Claude counts use Anthropic’s published ratios; use the count_tokens API for an exact number.

Price per million tokens

USD, standard tier. Prices checked on October 28, 2026.

Claude Opus 5.5GPT-6 Astra
Input$4$10
Output$20$50
Cached input$0.2$1
Cache write (5 min)$5Not charged separately
Long promptsSame price at any lengthAbove 272K tokens: $20 / $75
Batch API50% off50% off
ProviderAnthropic (Claude)OpenAI (GPT)

Monthly cost for common workloads

WorkloadClaude Opus 5.5GPT-6 Astra
Chatbot
1,500 input + 400 output tokens, 100,000 requests a month
$1,658$3,500
Document Q&A (RAG)
8,000 input + 500 output tokens, half the input cached, 20,000 requests a month
$680$1,380
Long-document summary
150,000 input + 2,000 output tokens, 1,000 requests a month
$898$1,600
Bulk classification (Batch API)
500 input + 20 output tokens, 1 million requests a month, Batch API where available
$1,630$3,000

Token counts are converted per model: the same text becomes a different number of tokens on each provider (see below). The cheaper option in each row is highlighted.

Frequently asked questions

Is Claude Opus 5.5 cheaper than GPT-6 Astra?

Per million tokens, Claude Opus 5.5 costs $4 / $20 (input / output) and GPT-6 Astra costs $10 / $50. For a typical chatbot workload (1,500 input + 400 output tokens, 100,000 requests a month), Claude Opus 5.5 is 53% cheaper: $1,658 vs $3,500 for GPT-6 Astra. Token counts differ between providers, so compare the cost of the same prompt rather than the price per token.

How much do Claude Opus 5.5 and GPT-6 Astra cost per million tokens?

Claude Opus 5.5: $4 / $20 for input / output, $0.2 for cached input. GPT-6 Astra: $10 / $50, $1 for cached input. Prices in US dollars, standard tier, checked on October 28, 2026.

Do Claude Opus 5.5 and GPT-6 Astra count tokens the same way?

Claude Opus 5.5 uses Anthropic's newer tokenizer, which produces about 30% more tokens than earlier Claude models. We estimate about 1.43× the GPT o200k count for the same text. GPT-6 Astra's tokenizer is not published; we use the o200k count, which is close for newer OpenAI models.

Do Claude Opus 5.5 and GPT-6 Astra have a Batch API discount?

Both do: Claude Opus 5.5 gets 50% off and GPT-6 Astra 50% off for requests sent through the Batch API, which may take up to 24 hours.

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