Number format: this calculator uses German notation throughout — a comma is the decimal separator and a dot groups thousands. “1.234,56” means one thousand two hundred thirty-four euros and fifty-six cents. The figures come from German tax law, so they are shown the way German authorities write them.
Billable hours
Only the time you actually invoice — not the time you work.
In plain language
The most common costing mistake among the self-employed: budgeting on 40 hours a week. In reality only part of that can be invoiced. Writing proposals, bookkeeping, finding clients, training, email — all of it is work, but nobody pays for it separately. Count the non-billable time as billable and you arrive at an hourly rate that is too low, and you work the whole year too cheaply.
In detail
There is no statutory definition and no official benchmark — which is why this figure is an input and not something this calculator prescribes. Two quantities go into it. First the working weeks per year: 52 minus holiday minus expected sick days; four weeks of holiday and two weeks of absence leave 46. Second the billable hours per week: in knowledge work the share is, by experience, well below the hours spent at the desk. That cannot be substantiated in general terms; only your own time tracking can.
Worked example
46 weeks × 25 billable hours = 1.150 hours a year. With 68.700 € of revenue needed, that comes to roughly 59,74 € per hour. Calculated on 40 hours instead of 25, you would arrive at 37,34 € — and the numbers would not add up.
In brief
Working weeks per year times billable hours per week.