How to Estimate Task Duration When Planning Resources

Categories: Resource Planning, Task Scheduling
Estimating tasks’ duration can be a huge factor when estimating projects’ course. Tasks are essentially what make a project what it is. So if you are estimating how long a project might take to complete, estimating tasks' length might be the right place to start.

Decide the Aim of the Task

If you are wondering whether to plan longer general tasks or short precise ones there is no one right answer. It all depends on your team and the way they are used to work. As you can see from the infographic below about 60% of tasks planned with Ganttic are 1-14 days long.

However, there is also a considerable amount of tasks that are shorter than one day and those that are longer than a month. If you are using resource planning software only for yourself and/or the management, and not for actually giving out tasks to your team, longer tasks might be it for you. If you need to guide and motivate your team through the resource planner, you might want to consider dividing those longer tasks into smaller ones.

For example, you can plan a month-long task called "Website Design" or you can have four shorter tasks called "Wireframes and Site Architecture", "Visual Design", "Site Development", and "Site Testing" with the same time sum. That's actually the first step to task duration estimation - decide what the aim of the task will be. 

tasks planned with ganttic

If you have done that, you can move on to other things that can help you to estimate how long the task you are planning should be.

Go Back in Time

There’s nothing new in this world. If you are not planning resources for aliens who are trying to take over the moon then the task you are planning has probably been planned before. Or at least something like it. 

If you are using our resource planning software, you can use the filtering feature to find all the tasks with the same name as you are planning. If you don’t, you should check Ganttic out. Hehe. Anyway, if there are tasks like the one you are planning, find them and inspect them.

Use Used Time Feature

This one won’t help you right now if you aren’t using it yet but it will in the future. Ganttic allows you to track the actual time it took to complete a task. Meaning if you have planned a task and then when your team member has completed the task, they can write down the used time. 

Later, you can use a report to calculate the difference so you can see whether you are over or underestimating the time it takes to actually complete the task. Or you get to treat yourself because you had estimated the time right.

The Best and the Worst Case Scenario

If there really is no place to cheat from and you are planning for aliens to take over the moon think about both the best and the worst case scenario. The best case scenario is the time it would take if everything goes right and the worst case scenario the time it would take if everything goes wrong. And then take the middle road between those two.  

Keep the Details in Mind

When estimating the best and the worst case scenarios keep the details in mind. Because the estimation is actually in the details. Think about how many people are connected to completing the task. 

As a rule, if there are more people involved in the task, it will take longer. Think about the meetings that can affect the course of the task. If the client is involved at that stage, take it into consideration. Breakdowns of the equipment. The other tasks that need to be completed at the same time. The lightning bulb that might break. The fail that might get lost. Everything.


Whether or not you are new to resource planning be honest about the things that you don’t know. If you are working on something new and there isn’t much history to go on or you don’t completely understand everything, ask someone that does. People usually don’t mind helping you out. If there isn’t an older and wiser project manager around, you can try consulting with the person you are planning the task for. Or you can try Googling. That always helps.

As you can see, resource planning software can help you with many aspects of estimating tasks' length, and probably, there are even more ways to define how long the task you are planning should be. If you have some tricks and tips that aren't mentioned in the post - share them.