Effective rate is earnings over every hour
Multiply your billable rate by the hours you actually bill for your weekly earnings, then divide by all the hours you work. An admin hour spent without billing does not reduce your rate - it dilutes the earnings across more hours, which is exactly why the per-hour figure falls even though the rate itself is unchanged.
A freelancer billing 25 of 40 hours at $150 earns a $3,750 week, but spread across every working hour that is only about $94, not $150. The annual figure scales that same week by a working year of 48 paid weeks (the common freelancer count that leaves four weeks off), so it is the identical arithmetic moved out to a year rather than a separate guess.
Because total hours can equal or exceed the billable ones, the denominator is always the real cost of the week: it includes the admin, the email and the proposals that a pure billing rate ignores, and the headline answers what your working time actually paid per hour, not what you chose to charge.
Non-billable hours carry a hidden cost
Every non-billable hour costs you its opportunity value at your billable rate. The page shows that total - the money you lose to admin, email, proposals and learning that nobody pays for - built from the gap between the hours you work and the hours you bill.
This is the arithmetic behind hiring out tasks: if you can pay someone to do an hour of admin for less than your effective rate, and use that hour to bill, you come out ahead. The hidden-cost figure is the comparison you bring to that decision.
Because the hidden cost is the unbilled hours times the billable rate, it grows even when utilization holds still: an hour of admin at $150 costs the same whether it is one of forty hours or one of thirty, so the number keeps the price of the unbilled time visible instead of letting it disappear into the week.
Utilization is the honest share of your week
The share of your working hours that actually bills is your utilization rate - commonly 55%-75% for freelancers. Raising it means billing more of the hours you already work rather than simply working longer, because utilization is a fraction of the same week, not an extra hour stacked on top of it.
The calculator connects utilization to money: each extra billable hour in a week moves both your effective rate and your annual income in the same step. Billing 26 hours instead of 25 of a 40-hour week lifts the effective rate while leaving the working week the same size.
The page shows the utilization percentage next to the rate on purpose, so a dip in the headline figure is read for what it is - a utilization story, not a story about charging less. It is the lever that works within the hours you already live.
What the effective rate is not
It is not a billing rate and not a target for what to charge: it is what the week actually paid, averaged across every hour the week consumed, including the hours nobody was invoiced for. The billable rate you type stays untouched; the effective rate is a different, lower number that reflects the real shape of the week.
Nor is it a productivity verdict. A week with fewer billable hours may be a week of proposals that turn into next quarter income, and this arithmetic cannot see that - it prices the hours you gave, and leaves the judgment about them to you.
This page is an estimate from the numbers you enter, not a return and not tax advice; it assumes the weekly pattern holds so you can compare one mix of hours against another rather than forecasting a specific paycheck.
The 168 hours in a week and the 48-week year
Total hours cannot exceed the 168 hours a week anyone actually has, which is why that field is capped there instead of at the money ceiling: a week has a hard floor and a hard ceiling. Enter what you really work, evening admin included, because leaving hours out raises the effective rate by hiding work rather than by earning more.
The annual figure multiplies the week by 48, not 52. Four weeks of unpaid vacation, sick days and public holidays is the convention most freelancers plan against, and it is the difference between a number you can budget with and an optimistic one. Take two weeks instead and the year is 50 weeks, which lifts every annual figure by about 4%; the page follows the convention rather than guessing your calendar.
What the page cannot see is the work that pays later: proposals, learning, and the call that becomes next quarter's retainer. Those hours land here as non-billable, which is the honest accounting, and their return appears in a future week rather than in this one.
Danfio