Doing a material takeoff right means you'll order only the materials you need, in the quantities and types you need. This can not only save you on money and labor costs, but also minimize the amount of waste generated by your construction process.

A bad takeoff, on the other hand, can lead to ordering more material than you need. It can also throw off your bid. If the bid’s too high as a result, you could lose the project. If it’s too low, you could lose money through cost overruns.

Estimating isn’t easy. It takes know-how and time. To get takeoffs right and avoid common pitfalls, follow these tips.

Use a master checklist

The number one piece of advice estimators offer is to use a checklist that accounts for every potential item included in a typical takeoff. Omissions are a leading cause of project cost overruns. It’s not unusual for even experienced pros to omit soft costs such as permits and fees, less-obvious costs such as dumpsters and temporary power, and end-of-job costs such as landscaping and touch-ups. Update your checklist on an ongoing basis to account for items you missed in the past.

Use accurate materials costs

Getting accurate material costs can be tricky, particularly with ongoing market fluctuations. Estimating books can’t be accurate to every local market, and the numbers are often too high. It’s best to use these books for ballpark figures only and create your own cost lists based on project history. If you do use a cost book, go back at the end of every project and compare the book’s prices against your invoices. When the invoice price is higher, replace the book price with your invoice price. (Some software tools can do this automatically.)

To avoid discrepancies between projected and actual costs, commit to material choices early and aim to lock in prices from your suppliers.

Avoid cringe-worthy math mistakes

When doing takeoffs manually, it’s all too easy to enter a number wrong, double count an item or make a simple arithmetic error that can lead to cost overruns later. If you’re doing manual takeoffs, have someone double-check your work to ensure you’ve pulled the right numbers from the drawings and that you are using the right units of measurement. When you’ve been staring at a takeoff for hours, you’re likely to gloss over errors. Some apps and online solutions can also help identify measurement errors.

Don’t expect software to do the whole job for you

Digital tools can deliver incredibly accurate measurements — but those may not always be the right measurements for material ordering purposes. One estimator new to Revit commented on an Autodesk forum that manual and digital areas calculated for one ceiling were significantly different because the Revit tool excluded the area taken up by light fixtures and air terminals — an area for which materials are still needed.

Don’t let software think for you. Digital tools and experienced human estimators should act as checks and balances on each other.

Consider integrated software tools

Moving beyond manual takeoffs to digital takeoffs is a natural progression if the owner is supplying digital blueprints. There are plenty of apps that can help you analyze digital blueprints and will start the takeoff for you. But if you then have to transfer the information manually into your bidding program, you open yourself up to making data entry mistakes. Using software that automatically transfers the data into a bidding system is a better idea.

Better still: Consider using estimating software or BIM or Revit integrations that integrate with the design and engineering team’s platforms in real time so you know the blueprints you’re working with have the most up-to-date information. 

Many construction professionals still consider estimating as much art as science. But following these tips will boost the science quotient and help you achieve more accurate takeoffs so you can spend less, waste less and win more bids.

Megan Headley has been writing about every aspect of the built environment since 2004. As owner of ClearStory Publications, LLC, Megan demonstrates her passion for helping contractors create more productive and safer jobsites, and more sustainable and successful projects.