Planning a project is not only about deciding what work needs to be done. You also need to know how much time you have to finish it.
For freelancers, companies, and project managers, calculating working days is an important part of meeting deadlines, managing budgets, and keeping clients happy.
A project that takes 20 working days does not always take four calendar weeks. Weekends, public holidays, and personal days off can make the total time longer.
In this guide, you will learn how to calculate working days, estimate work hours, plan realistic deadlines, and use our free Working Days Calculator to organize your projects.
What Are Working Days?
Working days are the days when a person or business normally works.
In many countries, the standard working week runs from Monday to Friday. Saturday and Sunday are usually non-working days.
However, this schedule is not the same for every business or country.
For example:
- An office may work Monday through Friday.
- A restaurant may work every day of the week.
- A hospital may operate 24 hours a day.
- A freelancer may work on weekends when needed.
Before calculating a project deadline, you need to know which days count as working days for that project.
Working Days vs. Calendar Days
A calendar day is any day on the calendar, including weekends and holidays.
A working day is a day included in the project’s work schedule.
Consider this example:
A freelancer starts a project on Monday and needs five working days to finish it.
| Day | Project status |
|---|---|
| Monday | Working day 1 |
| Tuesday | Working day 2 |
| Wednesday | Working day 3 |
| Thursday | Working day 4 |
| Friday | Working day 5 |
The project can be completed on Friday if the work begins on Monday and there are no holidays or other interruptions.
But if the project requires 10 working days, it will normally take two working weeks, or 14 calendar days when counted as a full two-week period.
This difference is important when you promise a delivery date to a client.
Why Working Days Matter in a Contract
When a freelancer signs a contract, the delivery date should be clear.
A contract that says “delivery in 10 days” can mean something different from “delivery in 10 working days.”
If a project starts on a Friday, the difference can be even more important.
Example: A 10-Day Contract
Imagine a client hires a web developer on Monday, October 5, 2026.
The contract gives the developer 10 days to finish the project.
If the contract means calendar days, the deadline is October 15, assuming the start date is excluded and the first day counted is October 6.
If the contract means 10 working days, the deadline is October 19, assuming a Monday-to-Friday schedule and no holidays.
The exact result depends on the contract’s rules for counting the first day, weekends, holidays, and the delivery time.
This is why a contract should explain what “days” means.
What Should a Project Contract Include?
For better planning, consider defining these details:
| Contract detail | What it should explain |
|---|---|
| Start date | The date when the project begins |
| Working days | Which days count as workdays |
| Public holidays | Whether holidays are excluded |
| Delivery date | The expected date and time of delivery |
| Client feedback | How long the client has to review work |
| Changes | How extra requests affect the deadline |
For example, a contract could state:
“The project will be delivered within 15 working days, excluding Saturdays, Sundays, and public holidays observed by the service provider.”
This is an example of clear wording, not legal advice. Contract requirements can vary by country and business.
How to Calculate Working Days Between Two Dates
The easiest way to calculate working days is to select a start date and an end date, then remove the days that do not count as workdays.
For a standard Monday-to-Friday schedule, Saturdays and Sundays are excluded.
Public holidays can also be excluded if they apply to the project.
Step 1: Choose the Start Date
The start date is the date when the project begins.
For example:
October 5, 2026.
Step 2: Choose the End Date
The end date is the planned delivery date.
For example:
October 23, 2026.
Step 3: Exclude Weekends
If your business works Monday through Friday, do not count Saturdays and Sundays.
Step 4: Exclude Public Holidays
If a public holiday falls within the selected period and your business does not work on that day, remove it from the working-day count.
The result is the number of working days between the two dates.
Practical Example: Calculate a Project Deadline
Suppose a freelancer begins a website project on Monday, October 5, 2026.
The project requires 15 working days.
The freelancer works Monday through Friday and does not work on weekends.
There are no public holidays during the period.
The schedule looks like this:
| Week | Working days completed | Total |
|---|---|---|
| Week 1 | October 5–9 | 5 |
| Week 2 | October 12–16 | 10 |
| Week 3 | October 19–23 | 15 |
The project reaches 15 working days on Friday, October 23, 2026.
This example assumes the start date counts as the first working day.
If the contract begins counting on the next working day, the deadline will be different.
Use our Working Days Calculator to check the number of working days between your actual project dates.
How Public Holidays Affect Project Deadlines
Public holidays can change the number of working days available for a project.
Different countries have different public holidays. Some holidays also change dates from year to year.
For example, a company in Costa Rica may follow a different holiday calendar from a company in the United States or the United Kingdom.
A project manager should use the calendar that applies to the people doing the work.
Example: A Holiday During the Project
Imagine a project requires five working days.
It starts on Monday, and Wednesday is a public holiday. The business does not work on that holiday.
The schedule becomes:
| Day | Status |
|---|---|
| Monday | Working day 1 |
| Tuesday | Working day 2 |
| Wednesday | Public holiday |
| Thursday | Working day 3 |
| Friday | Working day 4 |
| Monday | Working day 5 |
The project finishes on the following Monday instead of Friday.
One public holiday added one calendar day to the planned working period in this example.
For longer projects, several holidays can move the delivery date by multiple days.
Check the Holiday Calendar
Before promising a deadline, check the holidays that apply to your project.
You can use our Holidays section to review holidays and plan around important dates.
Remember that some businesses operate on public holidays. If your project team works on those days, your calculation may be different.
How to Calculate Estimated Work Hours
Working days tell you how many days are available. Work hours tell you how much time people are expected to spend working.
These two measurements are related, but they are not the same.
For example, a project may have 10 working days available, but that does not mean the developer will work on the project for eight hours every day.
The developer may also have meetings, client calls, administrative tasks, or other projects.
Formula for Estimated Work Hours
Use this simple formula:
Estimated work hours = Number of working days × Work hours per day
For example, if a project has 10 working days and the developer plans to work six hours per day:
10 × 6 = 60 hours.
The estimated work time is 60 hours.
Example: A Freelance Website Project
Suppose a freelancer plans the following tasks:
| Task | Estimated hours |
|---|---|
| Planning and requirements | 6 |
| Website design | 12 |
| Front-end development | 20 |
| Testing | 8 |
| Client revisions | 6 |
| Total | 52 hours |
The total estimated work is 52 hours.
If the freelancer can spend four hours per working day on this project:
52 ÷ 4 = 13 working days.
The project needs approximately 13 working days of planned effort.
However, this calculation does not automatically include weekends, holidays, client delays, or time waiting for information.
Those factors should be considered separately when setting the final delivery date.
Why You Should Include Extra Time in Your Project Plan
Project estimates are not always exact.
A client may request changes. A technical problem may take longer than expected. Important information may arrive late.
For this reason, it is useful to include extra time in your project plan.
This extra time is often called a time buffer.
Example: Adding a 20% Time Buffer
Imagine your project requires an estimated 50 working hours.
You decide to add a 20% buffer.
First, calculate the buffer:
50 × 0.20 = 10 hours.
Now add the buffer to the original estimate:
50 + 10 = 60 hours.
Your adjusted estimate is 60 hours.
If you can work six hours per day on the project:
60 ÷ 6 = 10 working days.
The planned effort becomes 10 working days.
A time buffer does not guarantee that the project will finish on time. It simply gives you more room to manage small delays and unexpected tasks.
For large or complex projects, you may need a more detailed estimate.
How Delays Affect Project Budgets
When a project takes longer than expected, it can affect the budget.
This is especially important for freelancers who charge by the hour or have several clients.
Hourly Projects
Suppose you charge $30 per hour and estimate a project will take 40 hours.
The expected revenue is:
40 × $30 = $1,200.
If the project takes 50 hours, the total billed amount may be $1,500, depending on the contract.
However, if the contract has a fixed price, those extra 10 hours may reduce your profit.
Fixed-Price Projects
In a fixed-price project, the client agrees to pay a set amount for the work.
For example, you agree to build a website for $1,500.
If the project takes 40 hours, your effective hourly revenue is:
$1,500 ÷ 40 = $37.50 per hour.
If it takes 60 hours:
$1,500 ÷ 60 = $25 per hour.
The contract amount remains the same, but your effective hourly revenue changes.
This is one reason why realistic time estimates are important for freelancers and businesses.
How to Use Our Working Days Calculator
Our Working Days Calculator helps you calculate the number of working days between two dates.
It can be useful when planning:
- Project delivery dates.
- Freelance contracts.
- Employee schedules.
- Business deadlines.
- Academic assignments.
- Leave and vacation periods.
Step 1: Enter the Start Date
Select the date when the project begins.
For example:
October 5, 2026.
Step 2: Enter the End Date
Select the expected delivery date.
For example:
October 23, 2026.
Step 3: Select the Working-Day Rules
Choose the appropriate working days for your project.
For a standard office schedule, this is usually Monday through Friday.
If the calculator supports holiday settings, select the country or holiday calendar that applies to your project.
Step 4: Calculate the Result
Use the calculator to find the number of working days between the selected dates.
Review the result and confirm whether the start and end dates are included in the calculation.
Different calculators may use different counting rules.
Step 5: Plan Your Deadline
Use the result to estimate the time available for the project.
You can then divide the available time between planning, development, testing, and client feedback.
You can also use our Work Hours Calculator to estimate the number of hours available during the project.
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Working Days vs. Work Hours vs. Calendar Days
It is useful to understand the difference between these three measurements.
| Measurement | Meaning | Example |
|---|---|---|
| Calendar days | All days on the calendar | 14 calendar days |
| Working days | Days included in the work schedule | 10 working days |
| Work hours | Time spent doing work | 60 hours |
A project can have 10 working days and 60 estimated work hours.
But the actual delivery date depends on the project schedule, public holidays, and other delays.
For accurate planning, use all three measurements when necessary.
Table of Contents
Frequently Asked Questions
What is a working day?
A working day is a day when a person or business normally works. For many office jobs, working days are Monday through Friday, excluding public holidays.
How do I calculate working days between two dates?
Choose the start date and end date, count the days included in your work schedule, and exclude weekends and applicable public holidays.
Are Saturdays and Sundays working days?
For a standard Monday-to-Friday office schedule, Saturdays and Sundays are non-working days. However, some businesses work on weekends.
Do public holidays count as working days?
It depends on the project schedule and the applicable holiday calendar. If the business does not work on a public holiday, that day is normally excluded from the working-day count.
What is the difference between 10 working days and 10 calendar days?
Ten calendar days include weekends and holidays. Ten working days exclude the days that are not part of the work schedule, so they may cover more than two calendar weeks.
How do I calculate estimated project hours?
Multiply the number of working days by the number of hours you plan to work each day.
For example, 10 working days × 6 hours per day = 60 estimated work hours.
How much extra time should I add to a project?
There is no single buffer that works for every project. The amount depends on the complexity, uncertainty, client requirements, and possible delays. A simple project may need a smaller buffer than a large project with many unknowns.
Why is it important to calculate working days in a contract?
It helps both parties understand the expected delivery period and reduces confusion about weekends, holidays, and deadlines.
Can I use a Working Days Calculator for vacation planning?
It helps both parties understand the expected delivery period and reduces confusion about weekends, holidays, and deadlines.
Does a working-day calculator include public holidays automatically?
Not always. Some calculators allow you to select a country or holiday calendar, while others only exclude weekends. Check the calculator settings before relying on the result.
What is the difference between project duration and project effort?
Project duration is the total time between the project start and finish dates. Project effort is the amount of work required, often measured in hours or days of actual work.
A project may require 40 hours of effort but take several weeks to complete because of meetings, waiting periods, or other tasks.
Is the Working Days Calculator free?
You can use our online Working Days Calculator to plan project dates and calculate working days directly in your browser.
Plan Your Next Project With Confidence
Knowing how many working days you have is an important step in planning a successful project.
Whether you are a freelancer, student, business owner, or project manager, clear dates and realistic work estimates can help you organize your time.
Before starting your next project:
- Define the start and end dates.
- Identify the working days and public holidays.
- Estimate the hours required for each task.
- Add a reasonable time buffer.
- Confirm the deadline with everyone involved.
Ready to calculate your next deadline?
Use our free Working Days Calculator to count working days between dates and organize your project schedule.
You can also explore our Work Hours Calculator to estimate work time and our Days Between Dates Calculator to calculate the total calendar days between two dates.