Calculadora de Dias Úteis
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
dias úteis ≈ 5/7 × total
About this calculator
The Business Days Calculator is an online tool that quickly estimates how many business days are in a period of N consecutive days. It uses the approximate formula of 5/7 of the total days, considering a week has 5 business days (Monday to Friday) and 2 weekend days (Saturday and Sunday). This estimate is useful for initial planning, such as project deadlines, deliveries, or schedules, when you do not have details about specific holidays.
The operation is simple: you enter the total number of days (including weekends) and the calculator applies the 5/7 ratio to get the approximate number of business days. For example, 14 calendar days result in about 10 business days (14 × 5/7 = 10). Remember that this is an average estimate, as it ignores national, state, or municipal holidays, which can reduce the actual number of business days.
Use this calculator when you need a quick forecast without consulting detailed calendars. It is ideal for initial budgets, service delivery deadlines, or vacation planning. However, for precise calculations involving specific holidays, a more comprehensive calculator that considers local dates is recommended.
Caution: the formula assumes a standard 5-day workweek, which may not apply to all work schedules (e.g., 6x1 or 12x36 shifts). Additionally, holidays and optional days off are not considered, which can lead to significant differences in periods with many holidays, such as December and January. Always verify the result with an official calendar if accuracy is critical.
Frequently asked questions
How does the calculator estimate business days?
It multiplies the total days by 5/7, based on the proportion of business days in a standard week.
Why might the result differ from reality?
Because the formula does not consider holidays, optional days off, or work schedules different from the Monday to Friday week.
Can I use it to calculate business days in any country?
Yes, but remember that holidays and weekends vary. The calculator uses the standard 5-day workweek.
Does this tool replace an official calendar?
No. It is for quick estimates. For accurate calculations, consult a calendar with local holidays.
What is the margin of error for the estimate?
The margin depends on the number of holidays in the period. In months without holidays, the error is small; in months with many holidays, it can be larger.