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Specifications
Parameters
—253B
API pricing
Input price
$3.00—
Output price
$15.00—
Cached input price
$0.30—
Cheapest input
$3.00Amazon Bedrock—
Cheapest output
$15.00Amazon Bedrock—
Benchmarks
GPQA Diamond
83.4%76%
Overview
CompanyAnthropicNVIDIA
Release dateSep 29 2025Apr 8 2025
AccessClosedOpen Weight
Model detailsView modelView model

Frequently asked questions

Claude Sonnet 4.5 leads Llama Nemotron Ultra 253B on 1 of the 1 benchmark they both report (GPQA Diamond). Only Claude Sonnet 4.5 has a verified first-party API price: $3.00 per million input tokens and $15.00 per million output tokens. No pay-as-you-go API rate is tracked for Llama Nemotron Ultra 253B. Llama Nemotron Ultra 253B shipped 174 days before Claude Sonnet 4.5, so benchmark comparisons should account for the intervening progress.

Claude Sonnet 4.5 is closed, while Llama Nemotron Ultra 253B is open weight.

On GPQA Diamond, Claude Sonnet 4.5 leads at 83.4% vs Llama Nemotron Ultra 253B at 76%.