Compare AI models

Specifications
ParametersThe learned values that shape how a model responds. B means billion and T means trillion. For mixture-of-experts models, the total count is larger than the number active for each token. Parameter count alone does not measure quality.
—21B
Context windowHow much information the model can work with in one request, measured in tokens — pieces of words or other data. This includes your question, attachments, conversation and reply. Limits can vary by model variant and provider.
1M128k
API pricingUSD per 1M tokens · lower wins
Input priceWhat you pay for everything you send the model — your question, plus any documents or earlier conversation you include with it.
$10.00—
Output priceWhat you pay for the text the model writes back. It is normally the dearer half: producing an answer costs more than reading one.
$50.00—
Cached input priceA reduced rate for text you send over and over. If every request starts with the same instructions or the same document, the provider keeps a copy ready and charges less to read it again.
$1.00—
Cheapest inputLowest input rate across every provider on OpenRouter, the lab included. The cheapest endpoint may run a quantised build or a shorter context — see "Available from" on the model page.
$10.00Amazon Bedrock$0.018Darkbloom
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
$50.00Amazon Bedrock$0.09Darkbloom
$4,500Anthropic list price$8.10Darkbloom · fp8
Benchmarks
SWE-Bench VerifiedCoding — Real coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better.
95.5%60.7%
Humanity's Last Exam · with toolsMultidisciplinary reasoning — Humanity's Last Exam — extremely hard expert questions across many subjects. “With tools” means the AI is allowed to search the web or run code while answering. Higher is better.
64.5%17.3%
Overview
CompanyAnthropicOpenAI
Release dateJun 9 2026Aug 5 2025
AccessClosedOpen Weight
Model detailsView modelView model

Frequently asked questions

Claude Fable 5 leads gpt-oss-20b on 2 of the 2 benchmarks they both report (SWE-Bench Verified, Humanity's Last Exam). Only Claude Fable 5 has a verified first-party API price: $10.00 per million input tokens and $50.00 per million output tokens. No pay-as-you-go API rate is tracked for gpt-oss-20b. gpt-oss-20b shipped 308 days before Claude Fable 5, so benchmark comparisons should account for the intervening progress.

Context windows are 1M (Claude Fable 5) vs 128k (gpt-oss-20b). Claude Fable 5 is closed, while gpt-oss-20b is open weight.

On SWE-Bench Verified, Claude Fable 5 leads at 95.5% vs gpt-oss-20b at 60.7%. On Humanity's Last Exam · with tools, Claude Fable 5 leads at 64.5% vs gpt-oss-20b at 17.3%.