Compare AI models

Specifications
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.
1M1M
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.
$4.00—
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.
$20.00—
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.
$0.20—
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.
$4.00Amazon Bedrock$0.006Relace
Cheapest outputLowest output rate across every provider on OpenRouter, the lab included. May come from a different provider than the cheapest input.
$20.00Amazon Bedrock$0.2028Baidu
$1,800Anthropic list price$20.28Baidu · fp8
Benchmarks
BullshitBench v2Nonsense detection — Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better.
63%57%
Terminal-Bench 4.0Agentic terminal coding — Can the AI work in a command-line terminal — running commands and finishing technical setup tasks the way a developer would? Version 4.0 recalibrated how much time, CPU and memory each task gets, removed eight tasks and fixed nineteen, so fewer runs fail for reasons that have nothing to do with the model. Scores are not comparable with earlier versions. Higher is better.
66.4%31.2%
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.
67.7%63.9%
AutomationBenchBusiness workflows — Tests whether the AI can run real multi-step business workflows — the kind of end-to-end office processes companies want to automate — from start to finish. Higher is better.
40%54.8%
Chartography · with toolsChart tasks — A chart-centred test run with tools available to the AI, reported separately from the chart-reading benchmarks above it. Higher is better.
89%78.9%
threejsevalCommunity preference (Three.js) — Every model gets the same prompt — "the Eiffel Tower", "a glass fishbowl", "a robot arm picking toys into a box" — and builds a 3D scene in Three.js. Real people then see two scenes side by side, names hidden, and vote for the one they prefer. The votes become a chess-style Elo rating on threejseval.com, averaged across all the prompts. It measures whether the scene looks and moves right to a human eye, not whether the code passes a test. Higher is better.
20651634
Overview
CompanyAnthropicDeepSeek
Release dateSep 22 2026Sep 10 2026
AccessClosedOpen Weight
Model detailsView modelView model

Frequently asked questions

Claude Opus 5.5 leads DeepSeek-V4.1-Flash on 5 of the 6 benchmarks they both report. Only Claude Opus 5.5 has a verified first-party price for an available API: $4.00 per million input tokens and $20.00 per million output tokens. No currently available pay-as-you-go API rate is tracked for DeepSeek-V4.1-Flash. DeepSeek-V4.1-Flash shipped 12 days before Claude Opus 5.5, so benchmark comparisons should account for the intervening progress.

Context windows are 1M (Claude Opus 5.5) vs 1M (DeepSeek-V4.1-Flash). Claude Opus 5.5 is closed, while DeepSeek-V4.1-Flash is open weight.

On BullshitBench v2, Claude Opus 5.5 leads at 63% vs DeepSeek-V4.1-Flash at 57%. On Terminal-Bench 4.0, Claude Opus 5.5 leads at 66.4% vs DeepSeek-V4.1-Flash at 31.2%. On Humanity's Last Exam · with tools, Claude Opus 5.5 leads at 67.7% vs DeepSeek-V4.1-Flash at 63.9%. On AutomationBench, DeepSeek-V4.1-Flash leads at 54.8% vs Claude Opus 5.5 at 40%. On Chartography · with tools, Claude Opus 5.5 leads at 89% vs DeepSeek-V4.1-Flash at 78.9%. On threejseval, Claude Opus 5.5 leads at 2065 vs DeepSeek-V4.1-Flash at 1634.