Calculation note
Billable-hours tracking grew from professional services, agencies and consulting, where time is both a delivery constraint and a pricing unit. The useful calculation separates all work from client-chargeable work before revenue is forecast.
Utilisation starts with an honest calendar
A full workweek is not the same as a full billable week. Administration, proposals, internal coordination, learning, quality control and downtime consume real hours that cannot always be charged to a client.
Annual capacity needs leave and gaps
Using 52 weeks can overstate capacity when holidays, sick time, public holidays, seasonal shutdowns or unpaid gaps exist. The working-weeks input keeps that assumption visible.
Collected revenue is lower than theoretical billing
Even when hours are worked and invoiced, discounts, write-offs, disputes and late or failed payment can reduce collected revenue. The collection-rate field is a simple way to stop capacity planning from pretending every invoice is perfect cash.