Introduction
Choosing between GPT-4o and Claude 3.5 Sonnet is one of the most common decisions AI developers face. Both are flagship models from their respective companies, both are excellent at reasoning and coding, and both are priced in a similar range — but the details matter significantly at scale.
In this guide, we break down the exact costs, performance characteristics, and ideal use cases for each model.
Pricing Breakdown
| Model | Input (per 1M tokens) | Output (per 1M tokens) |
|---|---|---|
| GPT-4o | $2.50 | $10.00 |
| Claude 3.5 Sonnet | $3.00 | $15.00 |
At first glance, GPT-4o is cheaper on both input and output tokens. For most workloads, GPT-4o will cost 15-50% less than Claude 3.5 Sonnet.
Real-World Cost Examples
Example 1: Customer Support Bot
A typical customer support query might have:
- 500 input tokens (system prompt + user message)
- 300 output tokens (response)
| Model | Cost per Query | Cost per 10K queries/day |
|---|---|---|
| GPT-4o | $0.00425 | $42.50 |
| Claude 3.5 Sonnet | $0.00600 | $60.00 |
GPT-4o saves you ~$17.50/day or ~$525/month.
Example 2: Code Review Agent
Code review involves longer context:
- 2,000 input tokens (code + instructions)
- 800 output tokens (review comments)
| Model | Cost per Review | Cost per 1K reviews |
|---|---|---|
| GPT-4o | $0.0130 | $13.00 |
| Claude 3.5 Sonnet | $0.0180 | $18.00 |
Example 3: Document Summarization
Long-document tasks:
- 10,000 input tokens
- 500 output tokens
| Model | Cost per Doc | Cost per 1K docs |
|---|---|---|
| GPT-4o | $0.0300 | $30.00 |
| Claude 3.5 Sonnet | $0.0375 | $37.50 |
When to Choose Each Model
Choose GPT-4o when:
- Cost is the primary factor — it’s consistently cheaper
- You need multimodal inputs — GPT-4o has strong vision capabilities
- Your workload is high-volume — savings compound quickly at scale
- You use OpenAI’s ecosystem — Assistants API, function calling, etc.
Choose Claude 3.5 Sonnet when:
- You need long-context precision — Claude handles 200K token contexts excellently
- Writing quality matters — Claude’s prose and tone are often preferred
- You’re doing nuanced analysis — Claude tends to be more careful and thorough
- You want API simplicity — Anthropic’s API has excellent ergonomics
The Budget-Friendly Alternatives
If you’re primarily concerned with cost, consider:
- GPT-4o mini: $0.15 input / $0.60 output — 94% cheaper than GPT-4o
- Claude 3.5 Haiku: $0.80 input / $4.00 output — 73% cheaper than Claude 3.5 Sonnet
- Gemini 1.5 Flash: $0.075 input / $0.30 output — the cheapest capable model
For most applications, these smaller models deliver 80-90% of the quality at a fraction of the cost.
Conclusion
For pure cost efficiency, GPT-4o wins the comparison against Claude 3.5 Sonnet. However, Claude 3.5 Sonnet is competitive in quality and may be worth the premium for certain writing-heavy or long-context workloads.
Use our Token Cost Calculator to plug in your specific token counts and see the exact dollar difference for your use case.