CtrlAltDebrief

GPT-4o vs GPT-5.1

API pricing, context window and capabilities for GPT-4o and GPT-5.1, side by side. Prices are the cheapest listed serving route per 1M tokens, from LiteLLM and OpenRouter.

Verdict

computed from the published numbers

GPT-5.1 wins on price, on intelligence and on context window. Benchmark data is unavailable for one or both models.

Price
GPT-5.1
Terminal-Bench
Not called
Intelligence
GPT-5.1
Context window
GPT-5.1

Key takeaways

who wins on what, from the published numbers

GPT-4o wins

  • More serving providers (6 vs 5)
  • Supports audio

GPT-5.1 wins

  • Cheaper input ($2.50 vs $1.25 /1M)
  • Larger context window (131K vs 410K)
  • Higher max output (16K vs 128K)
  • Has reasoning mode
  • Has web search
Cheaper overall
GPT-5.1
$1.25 + $10.00 /1M
Larger context
GPT-5.1
410K
More providers
GPT-4o
6 providers

Pricing & specs

cheapest listed route · per 1M tokens
On-demand listed rates, OpenRouter routed quotes and Vercel reseller quotes. Enterprise commitments can be materially lower.
GPT-4oGPT-5.1
Input $/1M$2.50via OpenAI $1.25via Databricks best
Output $/1M$10.00via OpenAI $10.00via Databricks
Context window131K 410K best
Max output16K 128K best
Serving providers6 best5
DateReleased May 13, 2024 Released Nov 13, 2025

Benchmarks

Benchmark scores, side by side
GPT-4oGPT-5.1
Intelligence8.4 24.7 best
Terminal-BenchNot available 52%
GPQA Diamond54% 87% best
Output speed150 t/s best117 t/s
Latency (TTFT)0.79s best35.59s

Cost calculator

choose a serving route for each side
Input tokens / month
Output tokens / month
GPT-4o
via Gmi
$23
GPT-5.1
via Databricks
$16

Capabilities

feature support, side by side
FeatureGPT-4oGPT-5.1
Vision✓✓
Tool use✓✓
Reasoning—✓
Audio✓—
Prompt caching✓✓
Structured output✓✓
Web search—✓

Related comparisons

Frequently asked questions

Which is cheaper, GPT-4o or GPT-5.1?
GPT-5.1 is cheaper for input ($2.50 vs $1.25 per 1M tokens) from Databricks.
What is the context window difference between GPT-4o and GPT-5.1?
GPT-4o has a 131K-token context window and GPT-5.1 has 410K tokens, so GPT-5.1 can take a larger prompt.
How do GPT-4o and GPT-5.1 compare on benchmarks?
On the tracked benchmarks, GPT-5.1 leads on intelligence.
Listed prices from LiteLLM, OpenRouter and Vercel · last checked Oct 14, 2026

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