Simulating realistic Agentic workflow parameters (40,000 in / 1,500 out with 65% cache reuse). Claude Sonnet 5 delivers a 4% cost reduction over GPT-5.3 Codex.
| Traffic Volume Tier | GPT-5.3 Codex Monthly | Claude Sonnet 5 Monthly | Monthly Savings by picking Claude Sonnet 5 |
|---|---|---|---|
| 1,000 reqs/mo (Dev/Testing) | $50.05 | $48.20 | Save $1.85 / mo |
| 10,000 reqs/mo (Small App) | $500.50 | $482.00 | Save $18.50 / mo |
| 100,000 reqs/mo (Growth Production) | $5,005.00 | $4,820.00 | Save $185.00 / mo |
| 1,000,000 reqs/mo (Scale SaaS) | $50,050.00 | $48,200.00 | Save $1,850.00 / mo |
Claude Sonnet 5 is 4% cheaper for Agentic workflow workloads. At standard Agentic workflow parameter ratios (40,000 input tokens, 1,500 output tokens, 65% cache hit), Claude Sonnet 5 costs $0.0482 per request compared to $0.0501 on GPT-5.3 Codex.
GPT-5.3 Codex offers a context window of 256,000 tokens (max output: 64,000), while Claude Sonnet 5 offers 1,000,000 tokens (max output: 128,000).
At 100,000 requests per month, using Claude Sonnet 5 saves $185.00 every month (or $2,220.00 annually) compared to GPT-5.3 Codex.
Prompt caching is the single biggest lever — each step re-reads prior context. Summarize or prune tool outputs before appending them to the transcript. Cap the step budget; runaway loops are the #1 surprise on agent invoices.