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Gemini 2.5 Flash vs GPT-4o

API pricing, context window and capabilities for Gemini 2.5 Flash and GPT-4o, side by side. Prices are the cheapest listed serving route per 1M tokens, from LiteLLM and OpenRouter.

Verdict

computed from the published numbers

Gemini 2.5 Flash wins on price, on intelligence and on context window. Benchmark data is unavailable for one or both models.

Price
Gemini 2.5 Flash
Terminal-Bench
Not called
Intelligence
Gemini 2.5 Flash
Context window
Gemini 2.5 Flash

Key takeaways

who wins on what, from the published numbers

Gemini 2.5 Flash wins

  • Cheaper input ($0.15 vs $2.50 /1M)
  • Cheaper output ($0.60 vs $10.00 /1M)
  • Larger context window (1M vs 131K)
  • Higher max output (1M vs 16K)
  • More serving providers (8 vs 6)
  • Has reasoning mode
  • Has web search

GPT-4o wins

No clear edge on the tracked metrics.

Cheaper overall
Gemini 2.5 Flash
$0.15 + $0.60 /1M
Larger context
Gemini 2.5 Flash
1M
More providers
Gemini 2.5 Flash
8 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.
Gemini 2.5 FlashGPT-4o
Input $/1M$0.15via OCI best$2.50via OpenAI
Output $/1M$0.60via OCI best$10.00via OpenAI
Context window1M best131K
Max output1M best16K
Serving providers8 best6
DateReleased Jun 17, 2025 Released May 13, 2024

Benchmarks

Benchmark scores, side by side
Gemini 2.5 FlashGPT-4o
Intelligence9.8 best8.4
GPQA Diamond68% best54%
Output speed206 t/s best150 t/s
Latency (TTFT)0.47s best0.79s

Cost calculator

choose a serving route for each side
Input tokens / month
Output tokens / month
Gemini 2.5 Flash
via OCI
$1.35
GPT-4o
via Gmi
$23

Capabilities

feature support, side by side
FeatureGemini 2.5 FlashGPT-4o
Vision✓✓
Tool use✓✓
Reasoning✓—
Audio✓✓
Prompt caching✓✓
Structured output✓✓
Web search✓—

Related comparisons

Frequently asked questions

Which is cheaper, Gemini 2.5 Flash or GPT-4o?
Gemini 2.5 Flash is cheaper for input ($0.15 vs $2.50 per 1M tokens) from OCI. Gemini 2.5 Flash is cheaper for output ($0.60 vs $10.00 per 1M tokens) from OCI.
What is the context window difference between Gemini 2.5 Flash and GPT-4o?
Gemini 2.5 Flash has a 1M-token context window and GPT-4o has 131K tokens, so Gemini 2.5 Flash can take a larger prompt.
How do Gemini 2.5 Flash and GPT-4o compare on benchmarks?
On the tracked benchmarks, Gemini 2.5 Flash leads on intelligence.
Listed prices from LiteLLM, OpenRouter and Vercel · last checked Oct 14, 2026

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