Gemini 3.5 Flash is $0.5 cheaper per 1M input tokens (25% lower; 1.33x difference).
API cost decision in 10 seconds
Grok 4.5 vs Gemini 3.5 Flash
Pick Grok 4.5 for lower cost; pick Gemini 3.5 Flash only if the larger context window matters more.
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Data confirmed:
Prices normalized to USD per 1M tokens
Sample workload: 1M input + 500K output
Budget verdict
Pick Grok 4.5 for lower cost; pick Gemini 3.5 Flash only if the larger context window matters more.
On the standard 1M input plus 500K output workload, Grok 4.5 is estimated at $5 vs $6 for Gemini 3.5 Flash, saving $1 (16.7% lower).
Cost-first pickGrok 4.5
Context-first pickGemini 3.5 Flash
Sample savings$116.7%
10x traffic gap$10
Gemini 3.5 Flash has more context, but Grok 4.5 saves $1 on the standard workload. At 10x that traffic, the same price gap is about $10. Use the calculator below to replace the sample workload with your own token volume.
Cost sensitivity
Workload Sensitivity
Cost winner changes by workload shape: input-heavy / RAG favors Gemini 3.5 Flash, balanced workload favors Grok 4.5, and output-heavy chatbot favors Grok 4.5.
| Workload shape | Token mix | Better pick | Grok 4.5 | Gemini 3.5 Flash |
|---|---|---|---|---|
| Input-heavy / RAG | 5M input + 500K output | Gemini 3.5 Flash | $13 | $12 |
| Balanced workload | 1M input + 1M output | Grok 4.5 | $8 | $10.5 |
| Output-heavy chatbot | 1M input + 5M output | Grok 4.5 | $32 | $46.5 |
Grok 4.5 is $3 cheaper per 1M output tokens (33.3% lower; 1.5x difference).
Gemini 3.5 Flash has 548.58K more context (2.1x larger).
Grok 4.5 is $1 cheaper on the standard workload (16.7% lower).
Estimate your workload cost
Your Workload Cost
This estimate uses normalized public API pricing per 1M tokens. It is a planning aid, not a billing quote. Verify provider pricing, limits, and terms before production use.
Quick Decision
Gemini 3.5 Flash has the lower input price; Grok 4.5 has the lower output price; Gemini 3.5 Flash offers the larger context window. For the 1M input plus 500K output sample, Grok 4.5 is cheaper for the standard workload.
For a 1M input token plus 500K output token workload, the estimated API cost is $5 for Grok 4.5 and $6 for Gemini 3.5 Flash.
Choose Grok 4.5 when you care most about lower output-token price.
Choose Gemini 3.5 Flash when you care most about lower input-token price, and larger context window.
- On the standard 1M input plus 500K output workload, Grok 4.5 is estimated at $5 vs $6 for Gemini 3.5 Flash, saving $1 (16.7% lower).
- Grok 4.5 is $1 cheaper on the standard workload (16.7% lower).
- Gemini 3.5 Flash is $0.5 cheaper per 1M input tokens (25% lower; 1.33x difference).
- Grok 4.5 is $3 cheaper per 1M output tokens (33.3% lower; 1.5x difference).
- Gemini 3.5 Flash has 548.58K more context (2.1x larger).
| Feature | Grok 4.5 (SpaceXAI) | Gemini 3.5 Flash (Google) |
|---|---|---|
| Input Price prompt tokens per 1M | $2 | $1.5 |
| Completion Price per 1M tokens | $6 | $9 |
| Sample Workload Cost 1M input + 500K output | $5 | $6 |
| Context Window | 500K | 1.05M |
| Release Date |
Use-Case Decision Matrix
| Use case | Better pick | Why |
|---|---|---|
| Budget-constrained production | Grok 4.5 | On the standard 1M input plus 500K output workload, Grok 4.5 is estimated at $5 vs $6 for Gemini 3.5 Flash, saving $1 (16.7% lower). |
| High-volume input processing | Gemini 3.5 Flash | Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill. |
| Long responses and chatbots | Grok 4.5 | Lower output-token price matters most when assistants generate many completion tokens. |
| RAG or long-document work | Gemini 3.5 Flash | A larger context window leaves more room for retrieved passages, conversation history, or source files. |
Related Alternatives
- Grok Build 0.1 can replace Grok 4.5 when lower sample workload cost matters most: $2.
- Grok 4.3 can replace Grok 4.5 when lower sample workload cost matters most: $2.5.
- Grok 4.20 Multi-Agent can replace Grok 4.5 when lower sample workload cost matters most: $2.5.
- Grok 4.20 can replace Grok 4.5 when lower sample workload cost matters most: $2.5.
- Grok 4.20 Multi-Agent offers 2M context with $2.5 sample workload cost.
- Grok 4.20 offers 2M context with $2.5 sample workload cost.
- DeepSeek V4 Flash 0731 offers 1.31M context with $0.17 sample workload cost.
- DeepSeek V4 Flash Latest offers 1.31M context with $0.11 sample workload cost.
- DeepSeek V4 Flash 0731 · DeepSeek · #1
- MiMo-V2.5 · Xiaomi · #2
- Hy3 · Tencent · #3
- Ox Alpha · stealth · #4
Cheaper alternatives
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Open Google modelsGrok 4.5 is a model from SpaceXAI with frontier performance on coding, knowledge work, and STEM.
Gemini 3.5 Flash is Google's high-efficiency multimodal model, bringing near-Pro level coding and reasoning at Flash-tier cost and speed. It is highly optimized for coding proficiency and parallel agentic execution...