Side-by-side technical and economic comparison between OpenAI's GPT-6 Astra and OpenAI's GPT-5.6 Terra.
| Metric | GPT-6 Astra | GPT-5.6 Terra | Advantage |
|---|---|---|---|
| Provider Organization | OpenAI | OpenAI | — |
| Standard Input / 1M | $10.00 | $2.00 | GPT-5.6 Terra (80% lower) |
| Cached Input / 1M | $1.00 | $0.20 | GPT-5.6 Terra lower |
| Output / 1M | $50.00 | $12.00 | GPT-5.6 Terra lower |
| Context Window | 1.05M | 1.05M | Equal |
| Max Generation Tokens | 32k | 16.4k | GPT-6 Astra |
| Tokenizer Family | OpenAI o200k_base (200k vocabulary) | OpenAI o200k_base (200k vocabulary) | — |
| Workload (per month) | GPT-6 Astra | GPT-5.6 Terra |
|---|---|---|
| Chatbot10k requests · 500 in / 200 out | $150.00 | $34.00 |
| RAG app100k requests · 8,000 in / 1,200 out | $14,000.00 | $3,040.00 |
| Coding agent100k requests · 12,000 in / 2,000 out | $22,000.00 | $4,800.00 |
Standard rates, no caching or batch discounts. Model your own numbers below.
Opt for GPT-6 Astra when your engineering requirements prioritize OpenAI's ecosystem, specific tokenizer efficiencies (Exact BPE (o200k_base)), or when your expected prompt-to-completion ratios favor its $10/M input rate.
Opt for GPT-5.6 Terra when looking for OpenAI's tooling integration, specific context window depth (1.05M tokens), or when output generation volume favors its $12/M rate.
At a typical 3:1 input-to-output token mix, GPT-5.6 Terra is about 78% cheaper than GPT-6 Astra. GPT-6 Astra costs $10 per 1M input and $50 per 1M output tokens; GPT-5.6 Terra costs $2 and $12.
Both models have a 1.05M-token context window.
GPT-6 Astra: yes, cached input costs $1/1M. GPT-5.6 Terra: yes, cached input costs $0.2/1M.