Overage Revenue Calculator
The bill for a plan with an included allowance and a per-unit overage, what share of it the overage is, and the usage at which the next plan up becomes cheaper.
Usage-based plans bundle an allowance into a flat price and charge per unit past it.
How the overage revenue calculator works
Usage-based plans bundle an allowance into a flat price and charge per unit past it. The bill is the plan price plus the excess units at the overage rate, and the effective price per unit falls as the allowance is used and then rises again on overage.
The crossover is the usage at which paying for the next tier costs the same as the overage: past it, the customer is better off upgrading, and a well-set overage rate makes that point obvious.
Formula: bill = plan price + max(0, usage − included) × overage rate; crossover = included + (next price − plan price) ÷ overage rate
Worked examples
| Inputs | Bill for the month | Note |
|---|---|---|
| Growing customer | $179.00 | 4,000 over × 0.02 = 80 → 179; crossover at 17,500 |
| Inside the allowance | $99.00 | flat price only |
| Past the crossover | $339.00 | 12,000 over → 339, against 249 on the next plan |
FAQFrequently asked questions
How should an overage rate be set?
Above the effective per-unit price of the plan, so the allowance is the better deal, but not so far above it that a small overage feels like a penalty. Many providers set it so the crossover to the next plan lands a little past the allowance — nudging growing customers up rather than punishing them.
What is the crossover?
The usage at which the overage on the current plan equals the price difference to the next plan. Past it, upgrading costs less; the calculator reports it whenever a next plan is entered.
Does the effective price per unit matter?
It is what the customer compares against alternatives. It falls as they use more of the allowance and rises again once overage starts, which is the argument for a plan ladder rather than a single plan with heavy overage.
Should overage be billed in arrears or capped?
Uncapped overage billed in arrears maximises revenue but produces surprise bills; hard caps and spend alerts trade some revenue for trust. Whichever you choose, this calculator gives the bill the rules would produce.
Where these figures come from
- Reichheld (2003), Harvard Business Review — The One Number You Need to Grow — the paper that introduced Net Promoter Score
- Australian Securities and Investments Commission — the Australian corporate regulator
Last checked: September 2026. These are the industry-standard definitions; where companies commonly disagree, the page says so.