THE NUMORIX GUIDE
How to use the Subscription Calculator
Last reviewed September 14, 2026
What this calculator does
The engine sums each subscription's monthlyCost for total monthly cost and multiplies that rounded monthly total by 12 for total annual cost.
Formula and method
The engine sums each subscription's monthlyCost for total monthly cost and multiplies that rounded monthly total by 12 for total annual cost. It adds usesPerMonth across subscriptions and divides monthly cost by total monthly uses for average cost per use. Each row also gets a monthly cost, annual cost, and cost per use; a zero-use row receives a cost-per-use value of zero.
Variables and inputs
Add any number of subscriptions with a name, monthly cost in dollars, and uses per month. The Display Period selector can be Monthly or Annual. It changes whether the view displays monthly or annual totals and row costs, but the engine always calculates from monthly cost and monthly uses.
Worked example
With Netflix at $15.49 for 20 uses, Spotify at $10.99 for 30 uses, and Gym at $49.99 for 12 uses, total monthly cost is $76.47 and annual cost is $76.47 x 12 = $917.64. Total uses are 62, so average cost per use is $76.47 / 62 = $1.2334, displayed by the view as $1.23.
How to interpret the result
The result shows recurring subscription cash flow and a usage-weighted average cost per use. Annual cost assumes each monthly price remains unchanged for twelve months; it is not a forecast of renewals, taxes, or promotions.
Common mistakes to avoid
Enter a monthly equivalent for an annual plan, count actual uses per month rather than days you could use it, and do not read a zero-use row's displayed $0.00 per use as evidence that the service is free. Check whether a subscription is shared before assigning uses.
Assumptions and limitations
The engine does not model annual billing discounts, price changes, taxes, add-ons, free trials, cancellation dates, family sharing, unused capacity, or different values for different uses. The period selector is display-only, and total cost per use is a simple ratio rather than a measure of value.