Claude Sonnet 4.5
$10.50
estimated usage cost
1,000 requests × (1,000 uncached input × $3.00 + 500 output × $15.00) / 1,000,000 = $10.50
base rates; no context pricing tiers are published.
Text generation / Anthropic
Claude Sonnet 4.5
Claude Sonnet 4.5 is a text generation model from Anthropic, available through the Impossibl API. Its published context window is 200,000 tokens. The advertised input rate is $3.00 per million input tokens. The advertised output rate is $15.00 per million output tokens.
api id: anthropic/claude-sonnet-4-5
how much does claude sonnet 4.5 cost?
published base api rates · usd per 1m tokens
- input
- $3.00
- output
- $15.00
- cache read
- $0.30
- cache write · default ttl
- $3.75
- cache write · 1h ttl
- $6.00
rates are published by the impossibl api. balance-purchase fees, taxes, tool charges, and workspace-specific pricing are separate.
specifications & capabilities
- creator
- Anthropic
- model type
- Text generation
- context window
- 200k tokens
- maximum output
- not published in the catalog
- input types
- text, image
- output types
- text
- tool calling
- not verified in the catalog
unknown means the public catalog does not establish that fact. a model's documented capabilities can differ from what a particular api supports.
estimate your usage
estimate your api cost
estimate text token usage for your workload. all amounts are in usd.
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.
compare more Text generation models
- Claude Fable 5$10.00 input / 1m tokenscompare →
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- Claude Haiku 4.5$1.00 input / 1m tokenscompare →
- Claude Opus 4.5$5.00 input / 1m tokenscompare →
independent benchmarks
Results from Artificial Analysis. Each configuration is listed separately. These evaluations describe the tested model configuration; performance and costs can differ on Impossibl. Last checked 2026-09-11.
Claude 4.5 Sonnet (Non-reasoning)
| Benchmark | Score |
|---|---|
| Intelligence Index | 19.34 |
| Omniscience Index | -9.37 |
| GPQA | 72.73% |
| Humanity’s Last Exam | 7.23% |
| CritPt | 0.00% |
| Terminal-Bench Hard | 28.79% |
| AA-LCR | 54.00% |
| MMMU-Pro | 65.20% |
| IFBench | 42.65% |
| Tau2 | 70.47% |
| LiveCodeBench | 59.05% |
| AIME 2025 | 37.00% |
| intelligence index (API) | 19.3 |
Unmeasured scores are omitted. API values retain their source units.
view source ↗Claude 4.5 Sonnet (Reasoning)
| Benchmark | Score |
|---|---|
| Intelligence Index | 21.18 |
| Omniscience Index | -0.08 |
| GPQA | 83.43% |
| Humanity’s Last Exam | 17.79% |
| SciCode | 45.72% |
| CritPt | 1.14% |
| Terminal-Bench v2.1 | 55.81% |
| Terminal-Bench v4.0 | 0.00% |
| Terminal-Bench Hard | 35.61% |
| AA-LCR | 72.33% |
| GDPval Elo | 989.26 |
| GDP.pdf All-pass | 5.20% |
| AutomationBench Partial | 14.08% |
| MMMU-Pro | 68.73% |
| IFBench | 57.28% |
| Tau2 | 78.07% |
| Tau Banking | 24.54% |
| LiveCodeBench | 71.43% |
| AIME 2025 | 88.00% |
| coding index (API) | 52.1 |
| agentic index (API) | 17.5 |
| intelligence index (API) | 21.2 |
Unmeasured scores are omitted. API values retain their source units.
view source ↗frequently asked questions
What is Claude Sonnet 4.5?
Claude Sonnet 4.5 is a text-generation model from Anthropic, available through the Impossibl API.
How much does Claude Sonnet 4.5 cost?
Claude Sonnet 4.5 costs $3.00 per million input tokens and $15.00 per million output tokens through the Impossibl API. Cache reads cost $0.30 per million tokens; cache writes cost $3.75 per million tokens; cache writes with one-hour retention cost $6.00 per million tokens. All rates are in USD.
What is the context length of Claude Sonnet 4.5?
Claude Sonnet 4.5 has a 200,000-token context window through the Impossibl API.
What inputs and outputs does Claude Sonnet 4.5 support?
Claude Sonnet 4.5 accepts text and image as input. Claude Sonnet 4.5 returns text.
How do I use Claude Sonnet 4.5 through an API?
Claude Sonnet 4.5 is available through the Impossibl API. Use anthropic/claude-sonnet-4-5 as the model identifier with /v1/chat/completions. The quickstart explains how to create an API key and send your first request.
When was Claude Sonnet 4.5 released?
Anthropic released Claude Sonnet 4.5 on September 29, 2025.
sources & coverage
this page describes Claude Sonnet 4.5 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.
model descriptions and release dates, where available, use the creator sources linked in the faq. api prices and limits use the impossibl catalog. benchmark results, where available, are credited to Artificial Analysis in the benchmarks section. report a correction →