AI model comparison

Claude Sonnet 4.5 vs GPT-4.1

Comparing two widely-used large-context flagship models for production agent and assistant workloads that mix long documents with structured extraction and tool calls.

Quick answer: GPT-4.1 lists lower prices than Claude Sonnet 4.5 ($2 vs $3 per 1M input, $8 vs $15 per 1M output) and a 1M-token context window versus 200k, while Claude Sonnet 4.5 is positioned around agentic reliability, tool calling and structured output.

Pricing & context

All figures below are list prices pulled directly from the Harpd pricing registry (last verified 2026-08-18). Prices change often — open each model’s source link to confirm before budgeting. Machine-readable copy: /data/llm-pricing.json.

MetricClaude Sonnet 4.5GPT-4.1
ProviderAnthropicOpenAI
Input / 1M tokens$3$2
Output / 1M tokens$15$8
Cached input / 1M tokens$0.3$0.2
Batch discount50% off50% off
Context window200,000 tokens1,000,000 tokens
SourceAnthropic pricing ↗OpenAI pricing ↗
GPT-4.1 lists the lower cost for this workload.

$1,800 vs $3,000 / month (100k calls, 5k in / 1k out)

Last updated
Methodology
Computed from list prices per 1M tokens; excludes prompt caching and batch discounts.
GPT-4.1 lists the larger context window.

1,000,000 tokens

Last updated
Harpd has not measured these two models head-to-head yet.

First benchmark: JSON extraction, 100 real tasks — target ship 2026-09-15

Last updated
Methodology
Until then, no performance win is claimed on this page — validate both models on your own tasks.
Claude Sonnet 4.5

Capabilities

Claude Sonnet 4.5 offers strong tool-calling and agentic reliability, well-regarded structured-output and long-document reasoning, with a 200k token context window and published prompt caching for repeat prefixes.

Best for

Agentic flows, tool calling, document-heavy reasoning and structured extraction inside a 200k-token window.

Limitations

200k tokens is the smaller context window of this pair, and at $3/$15 per 1M it lists above GPT-4.1 on both directions.

GPT-4.1

Capabilities

GPT-4.1 provides a 1M token context window, strong instruction-following and code generation, and prompt caching, making it a common choice for very long-context retrieval and code-heavy tasks.

Best for

Very long-context work up to 1M tokens, code-heavy generation, and lower list prices on general assistant workloads.

Limitations

For high-volume simple tasks cheaper mini-tier models exist, and only your own testing shows whether it holds your quality bar.

Recommendation

Both are strong general-purpose flagships, so the right pick depends on your workload rather than a fixed quality ranking. If your tasks stretch past 200k tokens or lean heavily on code, GPT-4.1’s larger window is worth testing; for agentic and document-heavy flows, Claude Sonnet 4.5 is a frequent default. Because price does not predict which passes your real tasks, validate both on a representative sample before committing.

Updated 2026-08-18. Sources: Anthropic and OpenAI official pricing pages (verified 2026-08-18); no Harpd-measured benchmark yet.

Methodology & sources

Prices on this page come from the Harpd pricing registry, which mirrors the officialAnthropic and OpenAI pricing pages and was last verified 2026-08-18. Capability notes summarize documented provider positioning — they are not Harpd measurements. Cheaper-cost claims are computed from the registry at a fixed reference workload, so they are reproducible from the published dataset. Read the pricing methodology and themodel replacement guide before switching a production workload.

Answer

Price tells you what a model costs. It does not tell you whether it can replace your current model on your real tasks.

Read the evaluation guide
Evidence

Related comparisons

Claude Sonnet 4.5 vs Gemini 2.5 ProGemini 2.5 Pro lists a lower input price ($1.25 vs $3 per 1M) and a 1M-token context window versus 200k; Claude Sonnet 4.5 lists a higher output price ($15 vs $10 per 1M) and is positioned around agentic reliability and structured output.GPT-4.1 vs Gemini 2.5 ProBoth list 1M-token context windows, but pricing splits by direction: Gemini 2.5 Pro lists the cheaper input ($1.25 vs $2 per 1M) while GPT-4.1 lists the cheaper output ($8 vs $10 per 1M), so which is cheaper depends on your input/output mix.DeepSeek V3 vs Claude Sonnet 4.5DeepSeek V3 lists roughly 11× cheaper input and 14× cheaper output than Claude Sonnet 4.5 ($0.27/$1.10 vs $3/$15 per 1M), trading a 128k context window, managed-flagship support and pricing stability for that gap.

Explore related tools

Model Compare

Side-by-side pricing and capability explorer for every model in the registry.

LLM Pricing

Full list-price table across providers, updated from official sources.

Benchmarks

Open benchmark data — methodology, datasets and published results.

Claude Sonnet 4.5 vs GPT-4.1, answered

Which is cheaper, Claude Sonnet 4.5 or GPT-4.1?
GPT-4.1 lists the lower cost at Harpd's reference workload (100,000 calls/month, 5,000 input / 1,000 output tokens): about $1,800 versus $3,000 per month at list prices (2/8 vs 3/15 USD per 1M input/output tokens). The mix matters: if your workload is output-heavy, recompute with the model compare calculator.
What is the main difference between Claude Sonnet 4.5 and GPT-4.1?
GPT-4.1 lists lower prices than Claude Sonnet 4.5 ($2 vs $3 per 1M input, $8 vs $15 per 1M output) and a 1M-token context window versus 200k, while Claude Sonnet 4.5 is positioned around agentic reliability, tool calling and structured output.
Which has the larger context window?
GPT-4.1 lists 1,000,000 tokens versus 200,000 for Claude Sonnet 4.5, according to the Harpd pricing registry (last verified 2026-08-18).
Which is better for coding?
Both list code generation among their documented strengths — GPT-4.1's official positioning emphasizes coding, and Claude Sonnet 4.5 is widely used for agentic coding workflows. Harpd has not measured a head-to-head coding benchmark yet (see the open benchmark program), so the honest answer is: run both on a sample of your own coding tasks and compare against the same rubric.
Which should I choose?
Both are strong general-purpose flagships, so the right pick depends on your workload rather than a fixed quality ranking. If your tasks stretch past 200k tokens or lean heavily on code, GPT-4.1’s larger window is worth testing; for agentic and document-heavy flows, Claude Sonnet 4.5 is a frequent default. Because price does not predict which passes your real tasks, validate both on a representative sample before committing.