Using GPT-4o-mini for Simple Tasks and GPT-4o for Complex Ones - Automatically

You are paying gpt-4o prices for tasks gpt-4o-mini handles just as well. If your application sends every request to your most capable model, you are not being safe - you are leaving money on the table and paying a reliability tax for headroom you rarely need. This post shows how to use gpt-4o-mini for simple tasks and gpt-4o for complex ones automatically, with three working approaches ranked by sophistication. The Cost Math First, the numbers. As of early 2025: gpt-4o-mini : ~$0.15 per 1M input tokens, ~$0.60 per 1M output tokens gpt-4o : ~$2.50 per 1M input tokens, ~$10.00 per 1M output tokens That is roughly a 15-17x difference on input, and a 16-17x difference on output. Now model a realistic workload: # Classification task: label an email as spam/not-spam classification_input_tokens = 200 classification_output_tokens = 10 # Synthesis task: summarize a 10-page document into executive memo synthesis_input_tokens = 2000 synthesis_output_tokens = 400 # Cost per request (in dollars) mi