Route easy calls to a cheap model, hard ones to a premium model — see the blended cost.
Routing is the biggest lever on an LLM bill because the traffic mix is lopsided — most requests are easy. Send those cheap, reserve the frontier model for the hard tail. Compare models on the AI cost calculator.
The AI Model Router Cost Calculator estimates the blended monthly cost of serving your API traffic across two models instead of one. You enter your calls per month, the input and output tokens per call, the share of traffic routed to the cheap model, and the per-million-token input and output prices for both the cheap and premium models. It applies each model's rates to its portion of the requests, sums the input and output token charges, and reports a combined monthly figure alongside the savings versus sending every call to the premium model. The main cost drivers are your total call volume, the tokens per call, the routing split, and the price gap between the two models.
The key trade-off to watch is quality versus cost: routing more traffic to the cheap model lowers the blended figure, but only some requests are simple enough to answer well without the premium model. Because output tokens are usually priced higher than input tokens, verbose responses can dominate the total even at a favorable split, so test the cheap model on your actual prompts and confirm its answers hold up before raising its traffic percentage.
Sending each request to the cheapest model that can handle it — small model for easy calls, frontier model for hard ones. A classifier or rules decide, and the blended cost lands far below all-premium.
Often 50–80%, since most real traffic is routine. The saving depends on how much you can safely send to the cheap model without hurting quality.
📚 New here? Learn how LLM API pricing works →
Cost at different volumes:
| Volume | Monthly | Yearly |
|---|