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Specifications
Parameters
—253B
API pricing
Input price
$5.00—
Output price
$25.00—
Cached input price
$0.50—
Cheapest input
$5.00Amazon Bedrock—
Cheapest output
$25.00Amazon Bedrock—
Benchmarks
GPQA Diamond
91.3%76%
Overview
CompanyAnthropicNVIDIA
Release dateFeb 5 2026Apr 8 2025
AccessClosedOpen Weight
Model detailsView modelView model

Frequently asked questions

Claude Opus 4.6 leads Llama Nemotron Ultra 253B on 1 of the 1 benchmark they both report (GPQA Diamond). Only Claude Opus 4.6 has a verified first-party API price: $5.00 per million input tokens and $25.00 per million output tokens. No pay-as-you-go API rate is tracked for Llama Nemotron Ultra 253B. Llama Nemotron Ultra 253B shipped 303 days before Claude Opus 4.6, so benchmark comparisons should account for the intervening progress.

Claude Opus 4.6 is closed, while Llama Nemotron Ultra 253B is open weight.

On GPQA Diamond, Claude Opus 4.6 leads at 91.3% vs Llama Nemotron Ultra 253B at 76%.