Is Claude 4.5 Sonnet or GPT-5.5 cheaper?

For a typical request (10,000 input + 2,000 output tokens), Claude 4.5 Sonnet is cheaper — about 45% less, or roughly $5000 saved per 100,000 requests. Claude 4.5 Sonnet runs $3/$15 per 1M input/output tokens; GPT-5.5 runs $5/$30.

Which has the larger context window?

GPT-5.5, at 1,050,000 tokens versus 200,000.

How accurate are these token counts?

Claude 4.5 Sonnet: Approximated with cl100k_base — drift typically <2% on English and code. GPT-5.5: 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-5.5: pricing & cost comparison

On input tokens, Claude 4.5 Sonnet is the cheaper of the two — 40% less per million ($3 vs $5). On output, Claude 4.5 Sonnet is 50% cheaper ($15 vs $30) — and since output is usually the dominant cost driver, that gap matters more than it looks.

Side by side

	Claude 4.5 Sonnet	GPT-5.5
Input / 1M tokens	$3	$5
Output / 1M tokens	$15	$30
Context window	200,000	1,050,000
Token-count accuracy	±2%	exact
Cost — 10,000 input + 2,000 output tokens	$0.06	$0.11

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-5.5 to $0.11. Across 100,000 requests that's a $5000 swing in favour of Claude 4.5 Sonnet. To run the numbers on your actual prompt, paste it into the calculator and toggle Compare across all models.

Close call — decide on output cost

Claude 4.5 Sonnet and GPT-5.5 are close enough on price that the tie-breakers matter more than the headline rate. Output tokens are usually the dominant cost driver, so weigh $15 vs $30 per 1M output first, then context window — GPT-5.5 carries the larger one at 1,050,000 tokens. They're different vendors, so factor in a small tokenizer calibration buffer on whichever side isn't exact.

See the full breakdown on the dedicated pages for Claude 4.5 Sonnet and GPT-5.5.

FAQ

Is Claude 4.5 Sonnet or GPT-5.5 cheaper?: For a typical request (10,000 input + 2,000 output tokens), Claude 4.5 Sonnet is cheaper — about 45% less, or roughly $5000 saved per 100,000 requests. Claude 4.5 Sonnet runs $3/$15 per 1M input/output tokens; GPT-5.5 runs $5/$30.
Which has the larger context window?: GPT-5.5, at 1,050,000 tokens versus 200,000.
How accurate are these token counts?: Claude 4.5 Sonnet: Approximated with cl100k_base — drift typically <2% on English and code. GPT-5.5: Exact tokenization via the canonical OpenAI vocab (o200k_base). The dollar math itself is exact once the token count is known.

Both prices are computed from tokenmath's verified pricing table. Rates sourced from www.anthropic.com and developers.openai.com, verified 2026-07-06. Vendor pricing changes often — confirm before you commit.