Overage

How it works

A plan sets an included volume for each billing period. The vendor counts your usage in its billing unit. If the count ends above the included volume, the difference is multiplied by the overage rate and added to the bill. The count starts again at zero in the next period.

A short example with made-up numbers: a plan includes 100 units and charges 1 cent per extra unit. You use 130. Overage is 30 units, so 30 cents is added to the base price.

Not every plan has an overage rate. The guide on what happens when you pass a plan's included volume covers the other rules a plan can use and where to find them.

When it matters

Overage matters in two moments. Before you buy, it tells you what a good month will cost: a plan with a low base price and a high overage rate can end up dearer than a plan with a higher base. After you buy, it is the line on the invoice that moves, so it is the one to watch in the middle of each period.

Paying overage now and then is fine. Paying it every month is one of the signals that you have outgrown the plan.

How it relates to attribution

What you measure decides what you pay. When the unit is an event, every extra event you record brings overage closer, so tracking events nobody reads has a price. When the unit is an attributed install, a successful campaign raises the bill directly. Airbridge Core is an example of the first kind, and the guide linked above works through its rate.^[1]