Compare AI models

Specifications
Context window
1M1.05M
API pricing
Input price
$2.00$10.00
Output price
$10.00$50.00
Cached input price
$0.20$1.00
Cheapest input
—$5.00OpenAI
Cheapest output
—$25.00OpenAI
Benchmarks
FrontierCode v1.1 (Main) · main split
52.1%53.3%
Terminal-Bench 4.0
70.6%57.9%
Overview
CompanyAnthropicOpenAI
Release dateSep 28 2026Sep 3 2026
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Claude Sonnet 5.5 and GPT-6 Astra are evenly matched across the 2 benchmarks they both report (FrontierCode v1.1 (Main), Terminal-Bench 4.0). Claude Sonnet 5.5 is cheaper on both input and output: $2.00 vs $10.00 per million input tokens, and $10.00 vs $50.00 per million output tokens. Figures are base-tier rates. GPT-6 Astra shipped 25 days before Claude Sonnet 5.5, so benchmark comparisons should account for the intervening progress.

Context windows are 1M (Claude Sonnet 5.5) vs 1.05M (GPT-6 Astra).

On FrontierCode v1.1 (Main) · main split, GPT-6 Astra leads at 53.3% vs Claude Sonnet 5.5 at 52.1%. On Terminal-Bench 4.0, Claude Sonnet 5.5 leads at 70.6% vs GPT-6 Astra at 57.9%.