How to Calculate Cut and Fill by Hand

An important step in site preparation for construction projects is calculating the cut and fill required to level the site. Cutting and filling involves removing (cutting) earth in places where the land is elevated above the desired height and moving it to areas where the ground level is lower than it needs to be (filling). It’s a technique that is widely used on construction sites to create an even land surface.

Before any cutting and filling can take place, precise calculations need to be made to show exactly where the cut needs to be done, where the fill needs to go, and how much earth needs to be imported or exported to site.

So how is this done? Read on to find out.

Calculation Methods

These days, cut and fill calculations can be done using software which simplifies and speeds up the process significantly. Prior to this, cut and fill calculations were worked out by hand, using either the grid or cross-section methods. Both required painstaking detail and accuracy and would often take all day to complete.

Today, most calculations are made by software. However, for those that are old school, or maybe just curious, here’s a quick overview of how the calculations were made by hand.

Grid Method

This method involves drawing horizontal and vertical lines over your site plan to divide it into grid cells of equal size. You then include the existing elevation and proposed elevation for each corner of the grid cells, and work out the difference between the two, as this will be cut or fill depth for that spot. When you’ve done this for every corner you add them up, average them, and perform further calculations that will end up giving you a total number of cuts and fills. The difference between these two numbers will show you if earth will need to be removed or brought onto site to complete the job.

Cross-Section Method

To calculate this way, you need to draw evenly spaced horizontal lines across the site plan, then plot out on graph paper the proposed and existing elevations of the site. The graph is used to calculate the cut and fill area for each cross section, the volumes, and the import and export for the entire site.