Is Claude 4.5 Sonnet or GPT-4o cheaper?

For a typical request (10,000 input + 2,000 output tokens), GPT-4o is cheaper — about 25% less, or roughly $1500 saved per 100,000 requests. Claude 4.5 Sonnet runs $3/$15 per 1M input/output tokens; GPT-4o runs $2.5/$10.

Which has the larger context window?

Claude 4.5 Sonnet, at 200,000 tokens versus 128,000.

How accurate are these token counts?

Claude 4.5 Sonnet: Approximated with cl100k_base — drift typically <2% on English and code. GPT-4o: Exact tokenization via the canonical OpenAI vocab (o200k_base). The dollar math itself is exact once the token count is known.

Claude 4.5 Sonnet vs GPT-4o: pricing & cost comparison

On input tokens, GPT-4o is the cheaper of the two — 17% less per million ($3 vs $2.5). On output, GPT-4o is 33% cheaper ($15 vs $10) — and since output is usually the dominant cost driver, that gap matters more than it looks.

Side by side

	Claude 4.5 Sonnet	GPT-4o
Input / 1M tokens	$3	$2.5
Output / 1M tokens	$15	$10
Context window	200,000	128,000
Token-count accuracy	±2%	exact
Cost — 10,000 input + 2,000 output tokens	$0.06	$0.045

What a real request costs

Take a representative turn — 10,000 input + 2,000 output tokens. Claude 4.5 Sonnet comes to $0.06, GPT-4o to $0.045. Across 100,000 requests that's a $1500 swing in favour of GPT-4o. To run the numbers on your actual prompt, paste it into the calculator and toggle Compare across all models.

Which should you pick?

These are different vendors, so a switch means a different API and a slightly different tokenizer — budget a small calibration buffer. GPT-4o give exact counts; the others land within a few percent. See the full breakdown on the dedicated pages for Claude 4.5 Sonnet and GPT-4o.

FAQ

Is Claude 4.5 Sonnet or GPT-4o cheaper?: For a typical request (10,000 input + 2,000 output tokens), GPT-4o is cheaper — about 25% less, or roughly $1500 saved per 100,000 requests. Claude 4.5 Sonnet runs $3/$15 per 1M input/output tokens; GPT-4o runs $2.5/$10.
Which has the larger context window?: Claude 4.5 Sonnet, at 200,000 tokens versus 128,000.
How accurate are these token counts?: Claude 4.5 Sonnet: Approximated with cl100k_base — drift typically <2% on English and code. GPT-4o: Exact tokenization via the canonical OpenAI vocab (o200k_base). The dollar math itself is exact once the token count is known.