Is Claude 5 Sonnet or GPT-5.5 cheaper?

For a typical request (10,000 input + 2,000 output tokens), Claude 5 Sonnet is cheaper — about 64% less, or roughly $7000 saved per 100,000 requests. Claude 5 Sonnet runs $2/$10 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 1,000,000.

How accurate are these token counts?

Claude 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 5 Sonnet vs GPT-5.5: pricing & cost comparison

On input tokens, Claude 5 Sonnet is the cheaper of the two — 60% less per million ($2 vs $5). On output, Claude 5 Sonnet is 67% cheaper ($10 vs $30) — and since output is usually the dominant cost driver, that gap matters more than it looks.

Side by side

	Claude 5 Sonnet	GPT-5.5
Input / 1M tokens	$2	$5
Output / 1M tokens	$10	$30
Context window	1,000,000	1,050,000
Token-count accuracy	±2%	exact
Cost — 10,000 input + 2,000 output tokens	$0.04	$0.11

What a real request costs

Take a representative turn — 10,000 input + 2,000 output tokens. Claude 5 Sonnet comes to $0.04, GPT-5.5 to $0.11. Across 100,000 requests that's a $7000 swing in favour of Claude 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 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 $10 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 5 Sonnet and GPT-5.5.

FAQ

Is Claude 5 Sonnet or GPT-5.5 cheaper?: For a typical request (10,000 input + 2,000 output tokens), Claude 5 Sonnet is cheaper — about 64% less, or roughly $7000 saved per 100,000 requests. Claude 5 Sonnet runs $2/$10 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 1,000,000.
How accurate are these token counts?: Claude 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 platform.claude.com and developers.openai.com, verified 2026-07-06. Vendor pricing changes often — confirm before you commit.