Design projects are similar to other software projects in relation to management and planning skill requirements. They however differ in respect of a lack of easily quantifiable elements which can provide structured data points for estimating effort and time for projects. Hence a common phenomenon for design project is cost overrun due to poor time estimation. Various research studies demonstrate a schedule slippage ranging from 41% to 258%, causing cost overrun to be in a range of 97% to 151% (Norris, 1971; Murmann, 1994), irrespective of noteworthy innovation in design technology. The need for the evolution of a new estimation methodology in an era of reduced product cycle times has become more pronounced, especially when surveys point out that unrealistic time and cost estimation owes to traditional estimation methodologies. The need is to define various developmental environments and project complexity levels through product functionality and complexity of requirements to form the basis of realistic estimation for effort, cost and time. 
Why Time Estimation Matters
Irrespective of the billing technique you use for billing your client for a software project, the primary step is to estimate time for the project as the client would want to have an idea about the timelines of delivery. Timing would establish how fast they can touch market which further helps them plan their marketing strategies or study customer need/behavior at a particular time of the year to do a usability study. As a developer, estimating time for your project helps plan your activities and tasks, allocate resources based on competency and skill required for particular tasks at variable project phases, manage and plan schedules if you are working on two different projects (through urgency level allotment to project activities depending on which needs attention first and for how long). These and many other project related activities get divided and described based on time estimates.
Are you Granular Enough?
Norden (1970) recorded that, a standard model of resource utilization exists, irrespective of work activities in a project lifecycle, which made him create a model of resource usage in design project. This was based on planning, design, model and release. This model points that duration is dependent on project complexity. 
So for accurate time estimation you need to keep in mind the deliverable size based on design complexity. Splitting the work task into the smallest unit of tasks would help estimate time for each one separately.
The fact of the matter is,if you look into past project history, you would find many similar projects defined differently, broken down differently and hence estimated differently – with variable estimates for similar sized projects. So the first task is developing consistency and standardization in work break down mechanisms which aims to translate complexity to simplicity. So break complexity into simplicity in a consistent framework –
• Designing, Development, Content development and distribution
• Releasing – Launching
The major activities as highlighted above should be broken down further to a more granular level. The focus should be to list down all the activities which in some form or other is going to involve time and trigger the system through some means. Hence all productive activities should be listed under broad categories.
Planning would include client meetings, gathering requirements, brainstorming and discussion. Prototyping would include creating a prototype site, reviewing and analyzing, seeking client approval, developing functional patterns, etc. Designing would include coding, content development and distribution, checking across variable browser functionality, optimizing. Testing would include carrying functional testing and client user acceptance testing, and Launching would include activities for making the site go live. 
After listing the various actions, you need to estimate time for each activity. You have to note that every sub stage has to be broken into a more granular level and include all tasks associated with the design project.
Let us understand this with an example. At content development stage you would include a blog and a news page. As a designer, you need to discuss with the client various parts and sub-parts.
So a blog page could have one or more of the following sub features:
• ADD/EDIT/DELETE Blog entry
• UPLOAD Image
• ATTACH FILE
• ADD COMMENTS
• COMENT FORM
• SUBSCRIBE to News Letter
At this stage you might think you have covered all items for estimation, but stay alert! When you have to create functionality ‘UPLOAD IMAGE’, you need to discuss with the client whether the image needs to have an
• Image resizing option
• Full screen viewing
• Image editing capability
• Content on image addition functionality
All these additional features are ‘nice to have’ but would punch additional hours into the time estimate and jack up the overall estimation hours. In the initial round-up, if the client insists on squeezing the time estimates, following a standardized approach would enable you to justify your estimates. You can explain why and how a particular functionality is estimated for certain hours. You can either propose to do away with a particular functionality or eliminate the ‘nice to have’ items with a basic feature design which stays within acceptable budget hours. Your client would not only understand the justification of your time estimates but would trust your standing as an all round designer, who has a deep understanding of the design and who defines his/her estimates realistically through sound groundwork. 
Hence following a detailed granular mechanism would enable capturing all requirements early allocating time for each one of them so that the time estimates do not go haywire at later stages of the project. It is useful to consider time for ‘other’ tasks such as project management, review time, holiday/leaves, client turnaround, repairing bugs etc.
An Estimation Tool will do the Rest of the Task…..
Using estimation software at this stage would save time for the estimator to carry out the estimation task. A granular breakdown of requirements simplifies the most important and complex tasks to simplicity – now you just need to put these tasks in an already formulated standardized template, put effort hours for each defined task, add validation types, add test environments (based on browsers and device types), adjust reuse factors and click ‘estimate’ to arrive at your final estimation hours. Tools such as Quick FPA can be useful in this regard. It helps to produce quick estimates with good accuracy – the only predefined criterion is a very good granular breakup of your requirements.
Keep Track of Time and Evaluate Further
The process is simple, standardized, organized, easy and realistic to produce justifiable time estimates. Additionally a time tracking mechanism can be used to keep track of the project management activities and have control over time allocated for each phase, extra time left to allow re-allocation, and evaluation of actual time taken and estimated for activities at later stage. Evaluation can help you to redefine your average and use your own historical data to set future values for the next web project. A comparative analysis of actual and estimated time estimates will enable you to calculate percentage variance in time estimates of each major activity and help define your effort model –which task takes how much time (realistic value). This can refine your estimates and also develop a win-win solution for yourself as well as the client!
Bashir, Hamdi A. and Vince Thomson.
“Estimating Effort and Time for Design Projects .” The Canadian Society of Value Analysis. 23 December 2015 <http://www.scav-csva.org/upload/publications/EffortEstimationThomson.pdf>. [1,2]
“How To Estimate Time For A Project.” 14 April 2009. Site Point. 23 December 2015 <http://www.sitepoint.com/how-to-estimate-time-for-a-project/>. 
“Effective Strategy To Estimate Time For Your Design Projects.” 11 June 2009. Smashing Magazine. 23 December 2015 <http://www.smashingmagazine.com/2009/06/effective-strategy-to-estimate-time-for-your-design-projects/>.