Calculator
Model Routing Calculator
Model routing lowers AI spend by sending easy requests to a cheaper capable model and reserving the premium model for hard requests. The blended cost is the traffic-weighted cost of the cheap path, the premium path, and any classifier overhead. Routing pays off when the cheap model handles enough traffic and the price gap is larger than the routing overhead.
Open the live Model Routing calculator - Router savings →
Example scenario
Suppose 70 percent of requests are routine and 30 percent need a premium model. If the routine path is much cheaper and the classifier overhead is small, the blended monthly bill can fall sharply without changing the hard-request experience. If most requests still fall through to the premium model, routing adds complexity with little savings.
What the inputs mean
- Cheap model: the model used for routine or low-risk requests.
- Premium model: the fallback for hard, high-value, or risky requests.
- Easy traffic share: the portion of requests the cheap model can safely handle.
- Classifier overhead: extra tokens spent deciding which path a request should take.
- Request shape: input and output tokens per request, multiplied by monthly volume.
What the result means
You get the blended monthly cost, the single-model baseline, total savings, savings percentage, and the break-even easy-share where routing starts to pay. Use the result to decide whether the routing logic is worth the operational complexity.
Assumptions
- Model rates are list per-token rates from the source-backed index, not negotiated discounts.
- The easy-share input is your product judgment; the calculator does not infer quality or safety.
- Classifier overhead is counted as real model spend and can erase savings when traffic volume is low.
- Savings are directional until you validate quality and fallback rates in production logs.
Where the prices come from
Token rates come from the source-backed pricing index, where every figure links to the provider's own page and carries a last-checked date. This tool reads those committed numbers; it never calls a provider or fetches live prices.
Formula and methodology
The calculator computes one cost for the cheap path and one cost for the premium path using the same request shape. It multiplies each path by its traffic share, adds classifier overhead, and compares the blended monthly cost against sending 100 percent of traffic to the premium model. The break-even easy-share is the point where blended routing cost falls below the premium-only baseline.
Interpretation guide
- Compare alternatives with the same workload assumptions.
- Stress-test output-heavy, retry-heavy, cache-miss, and power-user cases before committing budget.
- Verify source links and production logs before using the estimate for billing decisions.
Limitations before production billing decisions
Treat ByteCosts calculations as planning estimates, not final billing totals. Real invoices can differ because token mix, retry rate, cache hit rate, rate limits, taxes, gateway fees, regional pricing, and negotiated discounts change the effective cost.
Verify the provider source before production billing decisions, then compare the estimate with your own logs or invoice once production traffic is live.
Frequently asked questions
When does model routing save money?
Routing saves money when a cheaper model can handle enough requests and the price gap is larger than classifier and fallback overhead. If most traffic still goes to the premium model, routing adds complexity without much savings.
What is the easy traffic share?
It is the share of requests you believe the cheaper model can safely answer. The calculator treats it as an input because only your product logs and quality checks can prove which requests are safe to route.
Does the classifier cost matter?
Yes. A classifier or router call is still model spend. On low-volume products or small price gaps, that overhead can erase the savings from sending some traffic to a cheaper model.
Should I route every request first?
Not automatically. Start with low-risk, routine traffic and validate quality, fallback rate, and user impact before moving critical workflows onto a cheaper path.
Model Routing Calculator. ByteCosts. https://bytecosts.com/tools/model-routing/