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GPT-5 vs Grok 3 Fast
XOpenAI · 1M context | xAI · 128k context
Cost Calculator
💰 Grok 3 Fast saves $1,950.00/month (27% cheaper)
OGPT-5
Per request$0.0240
Daily$240.00
Monthly$7,200.00
Yearly$87,600.00
XGrok 3 FastCHEAPER
Per request$0.0175
Daily$175.00
Monthly$5,250.00
Yearly$63,875.00
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Choose GPT-5 when…
- ✓ Larger context window (1M vs 128k) — better for long documents
- ✓ Supports prompt caching — save up to 90% on repeated prompts
- ✓ Optimized for: Frontier tasks & agents
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Choose Grok 3 Fast when…
- ✓ Cheaper for RAG & document retrieval (lower input cost)
- ✓ 38% cheaper per input token
- ✓ Cheaper for generation-heavy workloads (lower output cost)
- ✓ Optimized for: Low-latency flagship tasks