Model Routing Savings Calculator

Model routing savings calculator

✓ Last verified: 2026-07-15· Source: official provider pricing page· Auto-monitored — report change →

The single biggest LLM cost lever isn't a discount — it's not sending every request to the expensive model. Route the easy ones to a cheap model and only escalate the hard ones. Enter your split and per-model prices to see the blended cost and monthly saving.

Routing beats every discount

Teams chase prompt caching, batch discounts and committed-use deals, but the largest savings almost always come from a blunter move: stop paying frontier prices for trivial work. A model cascade — also called model routing — sends each request to the smallest model that can do the job. Classification, short replies, data extraction and simple Q&A go to a cheap model that's often 10–30× cheaper per token; only the genuinely hard prompts escalate to the premium model. Because most production traffic is easy, shifting 60–80% of it to the cheap tier typically cuts the bill by half or more — and this calculator shows the exact figure for your split and prices, not a rule of thumb.

The router that decides can be as simple as a keyword rule, a length threshold, a tiny classifier, or a confidence check: let the cheap model answer first and only escalate when it signals uncertainty. The cost of routing itself is negligible, so the only real constraint is quality — how much traffic can ride the cheap model before answers degrade. Slide the share here against the dollar saving to find the point where the trade stops being worth it.

Once you've sized the split, price each leg precisely with the LLM token cost calculator, find the cheapest model for the easy tier with the cheapest LLM API ranker, and stack a second lever on top with the prompt caching savings calculator — routing and caching compound. For the whole picture, the AI app cost estimator rolls it all into one monthly bill.

How to use it

1. Pick a preset model pair or type your own per-million input/output prices for both models.
2. Enter monthly requests and the typical input/output tokens per request.
3. Slide the share of traffic you can safely route to the cheap model.
4. Read the blended cost, the monthly saving and the cost-cut percentage; use the table to see what each extra 10% is worth.

Common mistakes

Assuming you must route on input only. Output tokens are usually the expensive half — a cheap model with cheap output is where the big wins are. Over-routing. Pushing 95% to the cheap model looks great on the bill but tanks quality on the requests that needed the big model; size to the share your evals tolerate. Ignoring the escalation cost. If you run the cheap model and then the premium one on hard requests, those pay twice — count escalations as premium here. Forgetting prices move. Cheap-model prices have fallen sharply; re-check periodically because the break-even share shifts with them.

FAQ

How much does model routing typically save?

With a cheap model 10–30× cheaper and 60–80% of traffic routable to it, most teams cut spend 50–70%. The exact figure is your split times the price gap — this tool computes it.

What is a model cascade / router?

A system that tries the cheapest capable model first and escalates to a bigger one only when needed, using a rule, classifier or confidence check. Most of the quality, a fraction of the cost.

Does routing add latency?

A rule-based router adds almost none. A "cheap model first, escalate on uncertainty" design can add latency on the escalated minority, so route confidently-easy traffic directly when you can.

Can I combine routing with caching and batching?

Yes — they stack. Route to the cheap model, cache repeated context, and batch non-urgent jobs. Each lever multiplies the others; model the combined bill in the estimator.

Routing is the cheap version of this idea; distilling your own student model is the expensive one. Price the up-front commitment with the model distillation ROI calculator.

Estimate only. Model prices are reference figures and change frequently — verify current pricing with each provider.

Frequently asked questions

How much can model routing save on LLM costs?

It depends on two things: how much cheaper your small model is, and what fraction of traffic can safely go to it. Cheap models are often 10–30× cheaper per token than frontier ones, so if 70% of your requests are simple enough for the cheap model you typically cut the bill by 50–70%. This calculator multiplies your real split by your real prices to give the exact blended cost and monthly saving rather than a rule of thumb.

What is LLM model routing?

Model routing (also called a model cascade) sends each request to the smallest model that can handle it. Easy tasks — classification, short replies, extraction — go to a cheap fast model; only genuinely hard prompts escalate to an expensive frontier model. A router (a rule, a classifier, or a confidence check on the cheap model's answer) decides. The result is most of the quality of the big model at a fraction of the cost.

What routing rate do I need to break even on a smarter router?

Routing itself is almost free — a keyword rule or a tiny classifier costs near nothing. The real question is how high you can push the share going to the cheap model before quality drops. This calculator shows the blended cost at your current split and the all-premium baseline, so you can see exactly what each extra 10% of cheap-routed traffic is worth in dollars and decide if the quality trade-off is justified.