Claude Opus 5.5 vs OpenAI o1

rates, context and capabilities side by side on the impossibl api, and what the same workload costs on each.

the models at a glance: base rates, context window and modalities
specificationClaude Opus 5.5

anthropic/claude-opus-5-5

OpenAI o1

openai/o1

input · usd / 1m tok$4.00$15.00
output · usd / 1m tok$20.00$60.00
context window1mtokens200ktokens
modalities · in → out

takes text and image in, gives text out

takes text and image in, gives text out

pricing

base api rates by model
base api rates · usd per 1m tokensClaude Opus 5.5

anthropic/claude-opus-5-5

OpenAI o1

openai/o1

input$4.00$15.00
output$20.00$60.00
cache read$0.20$7.50
cache write · default ttl$5.00not published
cache write · 1h ttl$8.00not published

the estimate below prices one workload at these rates on every model.

specifications

published specifications by model
as publishedClaude Opus 5.5

anthropic/claude-opus-5-5

OpenAI o1

openai/o1

creatorAnthropicOpenAI
model typeText generationText generation
context window1,000,000tokens200,000tokens
input

takes text and image in, gives text out

takes text and image in, gives text out

outputtexttext
tool callingnot verifiednot verified
releasedsep 22, 2026dec 5, 2024
endpoint/v1/chat/completions/v1/chat/completions

unknown means the public catalog does not establish that fact. a model's documented capabilities can differ from what a particular api supports. see the model documentation for integration details.

benchmarks

benchmark scores by model, primary tested configuration
primary configurationClaude Opus 5.5

anthropic/claude-opus-5-5

no benchmarks yet

OpenAI o1

openai/o1

intelligence index · gateway ranknot measured15.2#68 of 90
coding indexnot measured39.7#46 of 60
omnisciencenot measured-11.1#54 of 86
gpqanot measured74.7%#70 of 88
humanity’s last examnot measured7.0%#76 of 89
ifbenchnot measured70.3%
livecodebenchnot measured67.9%
aa-lcrnot measured65.0%
tau2not measured62.6%
terminal-bench hardnot measured12.9%
critptnot measured0.3%

OpenAI o1 source ↗

each column describes the tested configuration named under the model; performance and costs can differ on impossibl. a score one model was not measured on is left blank rather than scored zero. indices are ranked against every model on the gateway with one. last checked 2026-09-11.

estimate your cost

one token workload, priced on every model at the published rates, in usd. change the numbers to match yours.

token workload

total input, including cached tokens

include billable reasoning tokens

the same token usage in each request

a subset of total input, never additional tokens

Claude Opus 5.5

anthropic/claude-opus-5-5

estimated usage cost

$14.00

1,000 requests × (1,000 uncached input × $4.00 + 500 output × $20.00) / 1,000,000 = $14.00

base rates; no context pricing tiers are published.

OpenAI o1

openai/o1

estimated usage cost

$45.00

1,000 requests × (1,000 uncached input × $15.00 + 500 output × $60.00) / 1,000,000 = $45.00

base rates; no context pricing tiers are published.

estimates use published impossibl api usage rates. configured billing adjustments, funding fees, taxes, and custom workspace rates are excluded and may change the final amount.

image and audio usage, cache creation, and additional tool charges are excluded. reasoning tokens count as billable output, even when they are not visible in the response.

summary

Claude Opus 5.5 and OpenAI o1 are available through the Impossibl API. they share the /v1/chat/completions endpoint; the model identifier selects the model for a request.

Claude Opus 5.5 is created by Anthropic. It has a 1,000,000-token context window. Base API pricing (USD): $4.00 per million input tokens; $20.00 per million output tokens.

OpenAI o1 is created by OpenAI. It has a 200,000-token context window. Base API pricing (USD): $15.00 per million input tokens; $60.00 per million output tokens.

Claude Opus 5.5OpenAI o1

this page compares Claude Opus 5.5 vs OpenAI o1 as listed by the impossibl public api. prices and availability come from that catalog, refreshed here every five minutes. this is an impossibl offering, not a comparison of independent hosting-provider quotes.

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