Local LLMs vs Cloud APIs — A Real Cost Comparison (2026)

"Just use ChatGPT" — sure, until your API bill hits $500/month. I've been running both local and cloud AI for over a year. Here are the real numbers. The Test Setup Cloud: OpenAI GPT-4o, Anthropic Claude Sonnet, Google Gemini Pro Local: Ollama with Qwen 3.5 9B (Mac Mini M4) + Qwen 3 Coder 30B (RTX 3060) Workload: ~500 queries/day — code review, content generation, customer support, data analysis. Monthly Cloud API Costs For 500 queries/day: OpenAI GPT-4o (200 queries): ~$90/month Anthropic Claude Sonnet (200 queries): ~$72/month Google Gemini Pro (100 queries): ~$25/month Total: ~$187/month Monthly Local Setup Costs Mac Mini M4 (already owned): $0 RTX 3060 12GB (used, eBay): $150 one-time Electricity 24/7: ~$12/month Total: ~$12/month ongoing Break-even: less than 1 month. Quality Comparison (What Surprised Me) For 80% of daily tasks, local models are good enough: General chat: Qwen 3.5 9B is roughly GPT-4o quality (~90%) Code generation: Qwen 3 Coder 30B is close to Claude Sonnet (~85