The 6 most common mistakes in construction cost estimation and how to avoid them?

Accuracy in cost estimation for construction projects is essential to ensure their profitability and completion within the allocated timelines. Unfortunately, some common mistakes in construction cost can easily skew these estimations. Let’s not forget that these errors can have serious ramifications, impacting not only budgets but also timelines and corporate reputations. This article shines a light on the 6 most frequent mistakes in cost estimation and offers practical advice on how to avoid them.

Overview of common mistakes in construction and solutions

Before diving into the details, it is important to understand that every construction project is unique, with its own trials and complexities. However, common mistakes in construction are frequently committed within the industry, regardless of project type. This guide will systematically go through each of the 6 most frequent cost estimation common mistakes, from the underutilization of technologies to ignorance of inflation. For each error, a suitable solution will be proposed to help professionals improve their estimation processes. Learning to navigate around the 6 most common mistakes in cost estimation and implementing effective solutions can make the difference between success and failure of a construction project

1. Underestimating the use of technologies

In the construction industry, using technology can be a real lever to improve the accuracy and efficiency of estimates, thereby helping to avoid the 6 most common mistakes in cost estimation. However, as the world is in full digital transition, the adoption of these technologies is not always widespread, and their underutilization can lead to significant estimation errors. Estimation software, like ESTIMATION and TAKEOFF , for example, use artificial intelligence and/or data analysis to enable the production of faster and more accurate estimates, minimizing the risk of human errors.

Solution: To stay competitive in an ever-evolving landscape, construction businesses should consider training their staff to use these important technologies, or hiring technology experts to handle the estimation process.

2. Ignoring the importance of accuracy

In construction, rigorous accuracy is a must, but is too often overlooked during estimates. Even minor errors can quickly accumulate to result in a significant underestimation of the total cost, with severe repercussions on the budget and project timelines.

Solution: Emphasizing accuracy from the outset of the estimation process should be standard. This may require the establishment of standardized estimation systems, double-checking calculations, or using estimation software to automate the process and reduce the potential for errors.

3. Neglecting indirect costs

Indirect costs, encompassing everything from overhead charges to administrative expenses, are often overlooked during construction project cost estimation. However, these costs can add up significantly over the course of the project. Not factoring these costs into the estimate can lead to a significant underestimation of the final project cost.

Solution: Conducting a thorough review of all cost factors associated with the project is a crucial step in creating an accurate estimate. It’s essential to consider all costs, both direct and indirect, when estimating a project. A painstaking review of every project component will ensure every potential expense is accounted for.

4. Forgetting the weather factor

Weather conditions can significantly impact the cost and schedule of a construction project. However, this crucial variable is often overlooked in cost estimation, which can lead to incorrect projections and unexpected delays.

Solution: Conducting a meticulous analysis of potential weather conditions for the location and duration of the project can help mitigate the impact of weather on project execution. By anticipating possible weather-related interruptions, estimators can devise more robust and realistic action plans.

5. Ignoring the impact of inflation

In an ever-changing economic world, the impact of inflation on construction materials and labor costs is often overlooked. This usually leads to expected costs being below reality. Indeed, inflation can significantly increase the actual cost of materials and labor over time, creating a gap between initial estimation and the final costs of the project.

Solution: It’s essential to factor in inflation when building cost estimates. This consideration should be reflected in the project budget. Ideally, a provision for inflation should be included in the budget. A margin of around 10% is a good ballpark figure and can help manage cost overruns.

6. Failing to consider unexpected situations

Construction projects often encounter unforeseen challenges that can significantly increase costs. Complications such as last-minute design plan changes, unexpected increases in materials prices, or on-site challenges can arise at any time. Not foreseeing these additional expenses in estimates can lead to unpleasant surprises and a budget explosion.

Solution: Anticipation is key when it comes to unexpected challenges. Including a contingency reserve in the project budget can help deal with these surprises and keep the project on track. This reserve might seem like an extra cost at the outset, but in the long run, it can save a project from significant and unforeseen cost overruns.


Construction cost estimation is a delicate task requiring both high expertise and appropriate tools. By understanding the 6 most common mistakes in cost estimation and instituting best practices, construction professionals.

Would you like to learn more about how to avoid common mistakes in your estimates? Consult our estimation software experts to help you make the best choice by scheduling an appointment now!

About ConstructBuy

ConstructBuy is the most accessible grouping of digital, modular, integrated and collaborative tools in the construction industry. Our platform was created to enable construction industry stakeholders (contractors, architects, general contractors and specialists) to facilitate their operations in the four stages of a project: planning, estimation, supply and execution. ConstructBuy customers can get several benefits by using it: simpler processes, easier relationships, more efficient days and more profitable projects. They even confirmed that they made fewer mistakes, made their employees happier and had more time to make the most of their tools.

Whether it’s for your calls and invitations to tender with the BID tool, your statements of quantities and your estimate with the TAKEOFF and ESTIMATION tools, or managing your employees’ time sheets with the TIME tool, rest assured that we will continue to be there to support you in the digitization of our industry.