The Demo vs Production Gap
Demo: "We'll use GPT-4 for customer support. Costs $2/day in testing!"
Month 1 production: $4,200 bill arrives.
Month 2: $6,800.
Finance: "What happened to $2/day?"
Why Microsoft's Calculator Is Wrong
Microsoft's Azure OpenAI pricing calculator shows token costs. It doesn't show:
- Hosting fees: $1,836/month minimum for fine-tuning
- PTU costs: $2,448/month minimum for dedicated capacity
- Embedding costs: Often more expensive than completions
- Token ratio reality: Output tokens cost 3x input tokens
Real Pricing (December 2025)
GPT-4o (Newest, Cheapest GPT-4 Class)
- Input: $0.005 per 1K tokens
- Output: $0.015 per 1K tokens
GPT-4 Turbo
- Input: $0.01 per 1K tokens
- Output: $0.03 per 1K tokens
GPT-3.5 Turbo
- Input: $0.0015 per 1K tokens
- Output: $0.002 per 1K tokens
Text Embedding (ada-002)
- $0.0001 per 1K tokens
- (Sounds cheap until you embed millions of documents)
Token Math That Actually Matters
1,000 tokens ≈ 750 words
Typical customer support query:
- User question: 50 tokens
- System prompt: 200 tokens
- Context from knowledge base: 1,000 tokens
- Response: 300 tokens
- Total: 1,550 tokens per interaction
Cost per interaction (GPT-4o):
- Input: 1,250 tokens × $0.005 / 1,000 = $0.00625
- Output: 300 tokens × $0.015 / 1,000 = $0.0045
- Total: $0.01075 per interaction
At scale:
- 1,000 queries/day = $10.75/day = $323/month
- 10,000 queries/day = $107/day = $3,225/month
The Hidden Costs
Fine-Tuning Hosting Fee
$1,836/month minimum just to host a fine-tuned model. Even if you use it zero times.
When worth it:
- High-volume specialized use case (>1M tokens/month)
- Accuracy improvement justifies $22K/year fixed cost
When not worth it:
- "Let's fine-tune for better results" (try prompt engineering first)
- Low-volume use cases
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