Person-day
The work of one person for one day, the unit used to size and charge project effort. Plural person-days; man-day is the older form.
Definition
A person-day, called man-day in older English usage, is the amount of work one person completes in one day. Teams use it to size project effort and to charge that effort to clients. The plural is person-days, and person-day is now the preferred wording.
Effort and price stay separate: the effort of a quote is measured in person-days, and each day is then priced with the average daily rate. A quote of 40 person-days at 500 EUR per day comes to 20,000 EUR excluding tax. The unit of effort and the price of that unit should never be confused. In scheduling, 4 people working 10 days equals 40 person-days whatever the calendar, while duration depends on how many people can be assigned.
Formula
Effort in person-days = number of people x number of days. Total price = person-days x average daily rate.
Example: 4 people x 10 days = 40 person-days; 40 person-days x 500 EUR = 20,000 EUR excluding tax.
Why it matters
Counting effort in person-days gives the whole team one shared reference. The estimate becomes a number of days of work, discussed separately from the price, so scope and rate can be adjusted without rebuilding the whole quote. Tracking days actually consumed against days quoted shows early when a project drifts past its budget, and the gap between the two figures teaches the team how to estimate the next assignment of the same type more accurately.
Improve person-day estimates and tracking
- 1
Estimate the work in person-days first, then price the quote from that person-day total, never from a round euro figure chosen upfront.
- 2
Track person-days consumed against the person-days quoted while the project runs, so overruns surface before the final invoice.
- 3
Keep a history of person-days quoted versus person-days consumed per project type to sharpen future estimates.
How Okouro shows it
In Okouro, missions carry budgets and timesheets record the days consumed, so quoted effort and consumed effort stay visible side by side per mission. A free plan lets you try this effort tracking without cost.