Gemini 3.8 Flash vs Grok 4.5
API pricing, context window and capabilities for Gemini 3.8 Flash and Grok 4.5, side by side. Prices are the cheapest listed serving route per 1M tokens, from LiteLLM and OpenRouter.
Verdict
computed from the published numbersGemini 3.8 Flash wins on price, on Terminal-Bench, on intelligence and on context window.
Price
Gemini 3.8 Flash
Terminal-Bench
Gemini 3.8 Flash
Intelligence
Gemini 3.8 Flash
Context window
Gemini 3.8 Flash
Key takeaways
who wins on what, from the published numbersGemini 3.8 Flash wins
- Cheaper input ($0.75 vs $2.00 /1M)
- Cheaper output ($3.75 vs $6.00 /1M)
- Larger context window (1M vs 500K)
- More serving providers (5 vs 3)
- Supports audio
Grok 4.5 wins
- Higher max output (66K vs 500K)
Cheaper overall
Gemini 3.8 Flash
$0.75 + $3.75 /1M
Larger context
Gemini 3.8 Flash
1M
More providers
Gemini 3.8 Flash
5 providers
Pricing & specs
cheapest listed route · per 1M tokensOn-demand listed rates, OpenRouter routed quotes and Vercel reseller quotes. Enterprise commitments can be materially lower.
| Gemini 3.8 Flash | Grok 4.5 | |
|---|---|---|
| Input $/1M | $0.75via Google best | $2.00via xAI |
| Output $/1M | $3.75via Google best | $6.00via xAI |
| Context window | 1M best | 500K |
| Max output | 66K | 500K best |
| Serving providers | 5 best | 3 |
| Date | Released Sep 2, 2026 | Released Jul 7, 2026 |
Benchmarks
Benchmark scores, side by side| Gemini 3.8 Flash | Grok 4.5 | |
|---|---|---|
| Intelligence | 40.9 best | 38.8 |
| Terminal-Bench | 88% best | 82% |
| GPQA Diamond | 95% best | 93% |
| Output speed | 145 t/s best | 63 t/s |
| Latency (TTFT) | 24.48s | 13.52s best |
Cost calculator
choose a serving route for each sideInput tokens / month
Output tokens / month
Gemini 3.8 Flash
via Vertex AI
$7.50
Grok 4.5
via OpenRouter
$16
Capabilities
feature support, side by side| Feature | Gemini 3.8 Flash | Grok 4.5 |
|---|---|---|
| Vision | ✓ | ✓ |
| Tool use | ✓ | ✓ |
| Reasoning | ✓ | ✓ |
| Audio | ✓ | — |
| Prompt caching | ✓ | ✓ |
| Structured output | ✓ | ✓ |
| Web search | ✓ | ✓ |
Related comparisons
Frequently asked questions
Which is cheaper, Gemini 3.8 Flash or Grok 4.5?
Gemini 3.8 Flash is cheaper for input ($0.75 vs $2.00 per 1M tokens) from Google. Gemini 3.8 Flash is cheaper for output ($3.75 vs $6.00 per 1M tokens) from Google.
What is the context window difference between Gemini 3.8 Flash and Grok 4.5?
Gemini 3.8 Flash has a 1M-token context window and Grok 4.5 has 500K tokens, so Gemini 3.8 Flash can take a larger prompt.
How do Gemini 3.8 Flash and Grok 4.5 compare on benchmarks?
On the tracked benchmarks, Gemini 3.8 Flash leads on Terminal-Bench, and Gemini 3.8 Flash leads on intelligence.
Listed prices from LiteLLM, OpenRouter and Vercel · last checked Oct 14, 2026
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