Claude Sonnet 5.5 vs GPT-6 Astra Pro
Pick up to 3 models · pricing, context and capabilities · simulate your product cost
Data updated on September 30, 2026· 217 models
Claude Sonnet 5.5 is Anthropic's Sonnet-class model for well-scoped everyday work, succeeding Claude Sonnet 5 as a direct upgrade.
- Reasoning estimated
- Speed estimated
- ▲
- Input
- Output
- Context
- 1 M tokens
- Max output
- 128 K
- Input, $ per 1M tokens
- ▲$2.00
- Output, $ per 1M tokens
- ▲$10.00
- Cache read, $ per 1M
- $0.200
- Batch (input / output)
- $1.00 / $5.00
- Tool calling
- Yes
- Released
- ▲09/28/2026
- Knowledge cutoff
- 2026-06
- API id
- anthropic/claude-sonnet-5.5
GPT-6 Astra Pro is the same underlying model as GPT-6 Astra, served with reasoning.mode set to pro for higher-quality responses on complex tasks.
- Reasoning estimated
- ▲
- Speed estimated
- Input
- Output
- Context
- ▲1.1 M tokens
- Max output
- 128 K
- Input, $ per 1M tokens
- $10.00
- Output, $ per 1M tokens
- $50.00
- Cache read, $ per 1M
- $1.000
- Batch (input / output)
- $5.00 / $25.00
- Tool calling
- Yes
- Released
- 09/04/2026
- Knowledge cutoff
- —
- API id
- openai/gpt-6-astra-pro
Which is the better API choice: Claude Sonnet 5.5 vs GPT-6 Astra Pro?
- Claude Sonnet 5.5: cheapest input (80% less than GPT-6 Astra Pro)
- Claude Sonnet 5.5: cheapest output
- GPT-6 Astra Pro: largest context (1.1 M)
- Claude Sonnet 5.5: the newest (09/28/2026)
- GPT-6 Astra Pro: most reasoning (estimated)
- Claude Sonnet 5.5: the fastest (estimated)
Claude Sonnet 5.5 costs 80% less on input and 80% less on output than GPT-6 Astra Pro ($2.00 / $10.00 versus $10.00 / $50.00 per million tokens). GPT-6 Astra Pro accepts more context (1.1 M). Claude Sonnet 5.5 and GPT-6 Astra Pro offer a batch tier at half price for jobs that do not need an immediate answer.
What would your product cost?
Estimate the monthly cost with your app's real volume. List prices, no cache or batch discounts.
With Claude Sonnet 5.5 you save $280.00 a month versus GPT-6 Astra Pro (80% less).
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Paste your prompt: tokens and cost per model
Rough estimate (about 4 characters per token). Nothing is sent to any server.
Cost of sending it 1,000 times (input only)
- 1Claude Sonnet 5.5 Anthropic$0.152
- 2Claude Sonnet 5 Anthropic$0.152
- 3Claude Opus 5.5 Anthropic$0.304
- 4Claude Opus 5 Anthropic$0.380
- 5Claude Opus 4.8 Anthropic$0.380
- 6GPT-6 Astra Pro OpenAI$0.760
- 7Claude Fable 5.1 Anthropic$0.760
- 8Claude Fable 5 Anthropic$0.760
Popular comparisons
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Frequently asked questions
Which is the better API choice: Claude Sonnet 5.5 vs GPT-6 Astra Pro?
Claude Sonnet 5.5 costs 80% less on input and 80% less on output than GPT-6 Astra Pro ($2.00 / $10.00 versus $10.00 / $50.00 per million tokens). GPT-6 Astra Pro accepts more context (1.1 M). Claude Sonnet 5.5 and GPT-6 Astra Pro offer a batch tier at half price for jobs that do not need an immediate answer.
Which is cheaper: Claude Sonnet 5.5 and GPT-6 Astra Pro?
Claude Sonnet 5.5 is cheaper: $2.00 per million input tokens and $10.00 per million output tokens, versus $10.00 / $50.00 for GPT-6 Astra Pro.
Which has more context: Claude Sonnet 5.5 and GPT-6 Astra Pro?
GPT-6 Astra Pro accepts 1.1 M tokens of context; Claude Sonnet 5.5 accepts 1 M.
Which is newer: Claude Sonnet 5.5 and GPT-6 Astra Pro?
Claude Sonnet 5.5 was released on 09/28/2026; GPT-6 Astra Pro on 09/04/2026.
What would 10,000 requests a month cost with Claude Sonnet 5.5 and GPT-6 Astra Pro?
With 1,500 input and 400 output tokens per request: Claude Sonnet 5.5: $70.00; GPT-6 Astra Pro: $350.00 a month, at list price.
Where do the prices come from and how often are they updated?
From the public catalogs of OpenRouter, models.dev and LiteLLM, which publish each provider's list prices. They sync once a day and the last update date is shown above the comparison.
What does price per million tokens mean?
It is what the provider charges per million tokens you send (input) or the model generates (output). A token is roughly 4 characters. Output almost always costs more than input.
Sources: OpenRouter, models.dev and LiteLLM. Prices in USD per million tokens, list price, no volume discounts. Prompt tokens are an estimate; each provider's tokenizer may differ.