What is a cut/fill map? A plain-English guide for construction and earthworks

A cut and fill map is one of the most useful pictures on an earthworks job. If you have searched “what is cut fill map”, this guide gives a plain answer. It explains what a cut and fill map shows and how teams read it on real jobs.

You will learn how cut and fill differ and how the map is made. We also cover how volumes are calculated and why accuracy affects budgets. The language stays plain, so you do not need to be a surveyor to follow along.

What is a cut/fill map?

A cut and fill map is a color-coded map that compares the existing ground with a target design surface. It shows where soil must be removed (cut) or added (fill), and how deep each change is.

The map is the difference between two surfaces, not the ground itself. Software takes the existing surface away from the design surface and paints the result.

Teams use a cut and fill map to plan earthmoving and measure volumes, then check progress against the design. It turns survey numbers into a picture the whole crew can act on.

Cut vs. fill: the two words explained

“Cut” is where the existing ground sits higher than the design. You remove soil to bring it down to the target level, called the grade.

“Fill” is the opposite. The existing ground sits lower than the design, so you add and compact soil to raise it to grade.

Picture a sloping field that has to become a flat building pad. You cut the high side, then move that soil to the low side as fill until both meet at the design grade.

How a cut/fill map is made

A cut and fill map needs two inputs. The first is the existing surface, a survey of the ground as it is today. The second is the design surface, the target grade set by the engineer.

Software subtracts one surface from the other. The gap between them at each point becomes the cut or fill value, and the colors you see on the map.

In practice, creating a cut and fill map in software follows a few steps:

1. Upload the survey data, such as drone photos or scans, and build the existing surface.

2. Make sure you have the earlier survey to compare against (either it has already been uploaded or you need to upload it now).

3. Let the software subtract the two surfaces and produce the colored map.

4. Work with the result and export a report with the cut/fill map if needed.

Today the existing surface is often built from drone photos. See our guide on how drones build 3D models for the full workflow. Accuracy depends on good survey control, which is where ground control points explained comes in.

AVAG can build that existing surface from more than one source. It can pull in drone imagery, laser-scanner data, 360° photos, and CAD files together, so a single model feeds the map.

Drawing a polygon on the 3D survey defines the area for earthworks analysis.

How to read a cut/fill map

Color is the fastest way to read a cut and fill map. Most tools follow a common convention rather than a fixed standard, so always check the map’s own legend first.

• Warm colors such as red usually mark cut, where the ground sits above the design.

• Cool colors such as blue usually mark fill, where the ground sits below the design.

• Stronger color means a greater depth of cut or fill at that spot.

• Pale or neutral areas are already close to the design grade.

Many maps also print a value at grid points or in a table. That number gives the exact cut or fill depth at a location, so you can read it in centimeters.

A map that is mostly pale, with little strong color, means the site is close to design and needs little earthmoving.

Because the map is color-coded, anyone can open it. AVAG shows the same 2D and 3D visualizations to everyone on the project, so results are not locked in one specialist’s software.

Blue areas show where the terrain has risen between the two drone surveys, indicating added material.

How cut and fill volumes are calculated

The colors show where to dig and fill. The volumes tell you how much, and there are a few ways to work them out. The map visualizes what these methods compute.

Modern platforms use the surface-to-surface method because it handles awkward ground well. For a deeper look at getting the numbers right, see how to measure earthworks accurately.

Why cut volume and fill volume are not interchangeable

A cubic meter of cut does not become a cubic meter of usable fill. Soil expands when you dig it, so the same earth takes up more room in the truck and less room once compacted.

The US Federal Highway Administration earthwork guidance says 1 cubic yard of cut fills about 1.25 cubic yards loose, then 0.65 to 0.85 once compacted.

This expansion is called the swell factor. According to Calichi’s soil swell factor guidance, most soils expand 20 to 30 percent when excavated, and one cubic yard is 27 cubic feet.

Plan haulage from loose volume, not the in-ground figure, or you will book too few trucks.

Where cut/fill maps are used on site

Cut/fill maps show up at every stage of an earthworks job. Before the dig, they help plan balanced earthworks, where cut soil is reused as fill on the same site to cut haulage.

During the work, the map tracks material movement week to week and compares the design grade to actual conditions. An earthworks analysis platform makes that comparison quick to repeat.

Site and project managers also use it to verify contractor work and confirm quantities before invoicing, which construction site monitoring supports. The same approach measures stockpiles and pits, so mining volume calculations rely on it too.

AVAG is used by construction and earthworks teams worldwide, including STRABAG, EUROVIA, Vinci Construction, and Colas. Surveyors and site managers open the same map as project engineers and quantity surveyors, so field and office share one set of numbers.

AVAG displays cut/fill changes over the drone orthophoto, showing where terrain levels have risen or fallen.

Why accurate cut/fill maps matter

Earthworks is often among the largest and most variable costs on a civil project. A wrong cut and fill figure feeds straight into bad haulage counts and costly rework, so accuracy has a direct price.

The Get It Right Initiative (GIRI) has measured this waste. A 2016 UK construction error costs report by GIRI put error at 10% to 25% of project cost, or £10–25 billion a year.

Faster, shareable surveys are one reason drone data is now common on site. Fact.MR expects the drone surveying market to grow from $2.4 billion (2026) to $13.7 billion (2036) at 19.0% CAGR, construction its top 39.2% segment.

The wider mapping software behind these tools is growing too. Per Global Market Insights, the global GIS market growth figures run from $11.6 billion in 2025 to $43.4 billion by 2035, a 14.6% CAGR.

Summary

Here is the short answer to what is cut fill map:

• A cut and fill map is a color-coded difference between the existing ground and a design surface.

• Cut removes soil where the ground is too high; fill adds soil where it is too low.

• The map is made by subtracting one survey surface from another.

• Warm colors usually mean cut and cool colors usually mean fill, with stronger color showing greater depth.

• Volume methods range from a cross-section approach for roads to a surface-to-surface comparison for whole sites.

• Swell means cut and fill volumes are not interchangeable, so plan haulage from loose volume.

• Accurate maps protect budgets, because earthworks errors are costly.

Try AVAG for cut and fill maps

Turn your drone or survey data into shareable cut and fill maps and reports your whole team can open. Try AVAG for free.

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