GPT-5.1 vs Claude Sonnet 4.5: token pricing & cost compared (July 2026)

How GPT-5.1 (OpenAI) and Claude Sonnet 4.5 (Anthropic) actually compare on price — input, output, and total monthly cost at the MAU you care about. Updated against live OpenRouter pricing.

OpenAI

GPT-5.1

Input: $1.25 / 1M tokens
Output: $10.00 / 1M tokens
Output / Input ratio: 8.0×
Context window: 400K

Anthropic

Claude Sonnet 4.5

Input: $3.00 / 1M tokens
Output: $15.00 / 1M tokens
Output / Input ratio: 5.0×
Context window: 1,000K

The short answer

GPT-5.1 is cheaper across the board for typical workloads.

Token pricing side-by-side

GPT-5.1
Claude Sonnet 4.5

Cost at your usage

Avg input tokens / call

Avg output tokens / call

Calls per active user / day: 5

Active days / month: 20

MAU: 1,000

GPT-5.1

Per call

$0.00563

Per user / mo

$0.5625

Total / mo

$563

Claude Sonnet 4.5

Per call

$0.00900

Per user / mo

$0.9000

Total / mo

$900

GPT-5.1 is cheaper by $0.3375/user/month — a saving of $337/month at 1,000 MAU.

Total monthly bill across MAU

GPT-5.1
Claude Sonnet 4.5

Same usage profile applied to both models; only the per-token price differs.

Run this against your real numbers

The mini-calculator above is a preview. Use the full tools to model power-user blast radius, gross margin, and 12-month spend forecasts.

Other comparisons

DeepSeek V4 Pro vs GPT-5.1 Claude Sonnet 4.6 vs GPT-5.1 GLM 5.2 vs GPT-5.1 Fable 5 vs GPT-5.1 o3 vs GPT-5.1 GPT-5.5 vs GPT-5.1

Comparing GPT-5.1 vs Claude Sonnet 4.5 on price alone never tells the whole story — output-token weighting, context length, and your usage profile change the answer dramatically. Use the calculators below for the full picture.