Is Claude 4.5 Sonnet or Gemini 3.1 Pro cheaper?

For a typical request (10,000 input + 2,000 output tokens), Gemini 3.1 Pro is cheaper — about 27% less, or roughly $1600 saved per 100,000 requests. Claude 4.5 Sonnet runs $3/$15 per 1M input/output tokens; Gemini 3.1 Pro runs $2/$12.

Which has the larger context window?

Gemini 3.1 Pro, at 1,000,000 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. Gemini 3.1 Pro: Approximated with o200k_base; drift typically ~3% on English and code. The dollar math itself is exact once the token count is known.

Claude 4.5 Sonnet vs Gemini 3.1 Pro: pricing & cost comparison

On input tokens, Gemini 3.1 Pro is the cheaper of the two — 33% less per million ($3 vs $2). On output, Gemini 3.1 Pro is 20% cheaper ($15 vs $12) — and since output is usually the dominant cost driver, that gap matters more than it looks.

Side by side

	Claude 4.5 Sonnet	Gemini 3.1 Pro
Input / 1M tokens	$3	$2
Output / 1M tokens	$15	$12
Context window	200,000	1,000,000
Token-count accuracy	±2%	±3%
Cost — 10,000 input + 2,000 output tokens	$0.06	$0.044

What a real request costs

Take a representative turn — 10,000 input + 2,000 output tokens. Claude 4.5 Sonnet comes to $0.06, Gemini 3.1 Pro to $0.044. Across 100,000 requests that's a $1600 swing in favour of Gemini 3.1 Pro. 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 Gemini 3.1 Pro 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 $12 per 1M output first, then context window — Gemini 3.1 Pro carries the larger one at 1,000,000 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 Gemini 3.1 Pro.

FAQ

Is Claude 4.5 Sonnet or Gemini 3.1 Pro cheaper?: For a typical request (10,000 input + 2,000 output tokens), Gemini 3.1 Pro is cheaper — about 27% less, or roughly $1600 saved per 100,000 requests. Claude 4.5 Sonnet runs $3/$15 per 1M input/output tokens; Gemini 3.1 Pro runs $2/$12.
Which has the larger context window?: Gemini 3.1 Pro, at 1,000,000 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. Gemini 3.1 Pro: Approximated with o200k_base; drift typically ~3% on English and code. 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 ai.google.dev, verified 2026-07-06. Vendor pricing changes often — confirm before you commit.