Claude Sonnet 5 vs GPT-5.4: which API costs less?
Averaged across three realistic workloads, Claude Sonnet 5 is about 28% cheaper than GPT-5.4. Below: raw rates and side-by-side monthly costs, computed from prices verified 2026-10-17 (we track what you are billed today, promos included).
Rates per 1M tokens
| Model | Input | Output | Cached input |
|---|---|---|---|
| Claude Sonnet 5Anthropic | $2 | $10 | $0.200 |
| GPT-5.4OpenAI | $2.50 | $15 | $0.250 |
Claude Sonnet 5: The $2/$10 launch price became the standard price; the planned increase to $3/$15 was cancelled. GPT-5.4: Prompts up to 272K tokens; longer prompts cost more.
Monthly cost, side by side
| Workload | Claude Sonnet 5 | GPT-5.4 | Difference |
|---|---|---|---|
Customer-support chatbot 2M input + 0.5M output tokens/month, 60% of input served from prompt cache | $6.84 | $9.80 | Claude Sonnet 5 −30% |
RAG / document Q&A 20M input + 1M output tokens/month, 70% cached (shared context) | $24.80 | $33.50 | Claude Sonnet 5 −26% |
Agentic coding assistant 50M input + 5M output tokens/month, 80% cached (long sessions) | $78.00 | $110 | Claude Sonnet 5 −29% |
Your traffic looks different? Run your own numbers in the calculator.
FAQ
Which is cheaper: Claude Sonnet 5 or GPT-5.4?
Across three realistic workloads (chatbot, RAG, agent), Claude Sonnet 5 works out about 28% cheaper than GPT-5.4 on average. Raw rates: Claude Sonnet 5 $2/$10 per 1M tokens vs GPT-5.4 $2.50/$15. Verified 2026-10-17.
Does prompt caching change the comparison?
Yes — cached input costs $0.200 on Claude Sonnet 5 and $0.250 on GPT-5.4. Our scenario numbers already include realistic cache hit rates.
Is cheaper always better?
No. Price is one axis — model capability, context window and latency differ. This page answers only the cost question; benchmark quality on your own tasks before switching.