Soil Calculator

Created by Kacper Pawlik, MD and Bogna Szyk
Reviewed by Dominik Czernia, PhD candidate and Jack Bowater
Last updated: Apr 06, 2022

We created this soil calculator as a tool to help you calculate how much garden soil you need - whether it is topsoil, compost, mulch, or topdressing. After all, you don't want to overspend on materials for your garden, do you? Keep reading to better understand how our topsoil calculator works, so you will never need to worry about those tedious calculations again!

For the curious reader, we have prepared information on topics that every farmer or amateur gardener should know. We will present a soil definition and explain where it comes from. We will also talk about the different types of soil and two processes that will help you when growing plants – soil conservation and soil degradation.

If you are in the middle of fulfilling your dream of building your own house, don't forget to check our concrete calculator to see how many bags of cement you will need!

image of hands holding handful of soil

How much soil do I need?

"How much soil do I need?" is a question frequently asked by people beginning their gardening and plant cultivation adventures. To answer this question, the first step is to establish the volume of soil needed. You can do it in the following way:

  1. Determine the length and width of the area you want to cover with soil. For example, we can assume a plot of length l = 14 yd and width b = 4 yd.
  2. Calculate the area, multiplying the length by width. In our case, A = 14 * 4 = 56 yd². You can also type the area directly into our calculator if you choose a more sophisticated shape. We've got area calculators for many geometric figures, such as the trapezoid or the hexagon. For even more examples, visit the 2D geometry section of our math calculators.
  3. Establish the depth – thickness of the topsoil layer. Let's say it's d = 0.5 yd.
  4. Multiply the area and dirt layer thickness to obtain its volume: 56 * 0.5 = 28 yd³.
  5. The volume of soil required is equal to this value. Our soil calculator will display it for you.

Different materials than topsoil? No trouble! Please take a look at our sand calculator or the gravel calculator, created precisely for this purpose.

All right, but how much is a yard of dirt?

To calculate the weight of a cubic yard of soil, you simply have to multiply the volume by its density. Just type the density of soil (you will probably find it on the packaging) into the topsoil calculator, and this calculation will be performed effortlessly.

Once you know the total weight of soil you have to buy, you won't have to worry about overspending on this material. But how much exactly will you spend? How much is a yard of dirt? Our dirt calculator can also help you with that – all you have to do is enter the topsoil price (per unit of mass, such as tonne, or per unit of volume, for example, cubic yard). The calculator will then display the total cost of the soil you need. Now it's the time to begin planning the plant spacing!

Dirt calculator – how to estimate garden soil quantity?

Let's deal with a real-life situation. Imagine that you have just built your beautiful house, with a roof finished with warm red tiles. You want to surround it with a grass yard and pavement made of tiles. To calculate the number of tiles and the amount of paver sand you need to buy before getting to work, we recommend you visit our tile and paver sand calculators. It would be a shame to buy too much or, even worse – not enough materials and have to go back to the home improvement store.

Now, let's get to the grass yard. We want to calculate the required quantity and cost of garden soil. As you can see, we cannot just type the width and length into our dirt calculator as there is a pool in the middle of it. How to deal with this problem?

plan of typical yard
  1. First, we need to divide the grass yard into four rectangles: 1, 2, 3, and 4.

  2. Now, we have to measure the width and length of each sector:

    • Sector 1 has a width of 2 yd and length of 25 yd;
    • Sector 2 has a width of 3 yd and length of 2 yd;
    • Sector 3 has a width of 3 yd and length of 10 yd;
    • Sector 4 has a width of 2.7 yd and length of 25 yd.
  3. Let's calculate the area of each rectangle:

    • Sector 1: area is equal to 2 yd multiplied by 25 yd, which gives 50 yd²;
    • Sector 2: area is equal to 3 yd multiplied by 2 yd, which gives 6 yd²;
    • Sector 3: area is equal to 3 yd multiplied by 10 yd, which gives 30 yd²; and
    • Sector 4: area is equal to 2.7 yd multiplied by 25 yd, which gives 67.5 yd².
  4. We have to sum up these four different areas to get the area of the whole yard:

    50 yd² + 6 yd² + 30 yd² + 67.5 yd² = 153.5 yd²

    You can already jump to the third point of topsoil calculator instruction in the How much soil do I need? paragraph.

  5. It is time to choose the desired thickness (depth) of the topsoil level. Let's make it 0.6 yd. We want to create enough space for grassroots to grow freely and without any obstacles. Furthermore, a thicker layer of topsoil will be able to absorb more water (learn how this affects a plant with our water potential calculator) and hold the moisture for a more extended period.

  6. You can calculate the required volume of soil by multiplying the grass yard area by the desired soil thickness.

    153.5 yd² * 0.6 yd = 92.1 yd³

  7. The last thing to do is assess the estimated weight of the required soil and its cost. The weight of the cargo may come in handy when transporting the soil. It would be nice to know that your truck or trailer will endure the burden of your purchase. As we have already mentioned, you should find the density of the chosen soil on its package. You just need to multiply it by the volume of our topsoil layer.

  8. And last but not least – money. Can you afford such an expense? Maybe we could save some money by reducing the thickness? To know that, you need to calculate the total cost. With our soil calculator, you can do it by multiplying the volume of purchased soil or its weight by the price of one cubic yard or price of one ton (other units of weight or volume are also available).

Oh, and if you were wondering whether we can also help you with finishing your interiors, yes, you're right – we've got calculators for that as well! You can organize the space with drywall and then paint the rooms using our drywall and paint calculators. Now, there is nothing left to do apart from relaxing in the cool water and inviting your friends for a barbecue!

What is soil? – Soil definition

Have you ever wondered what you are stomping on? Was it always here, or has it been here since eternity? Well, the easiest way to answer these questions would be to explain what the soil definition is. It is a mixture of things that have fallen or just found themselves on the ground. It consists of organic matter, liquids, gases, minerals, and living organisms.

The soil has been created by endless interactions between those ingredients, with the additional influence of some third parties, such as climate, weather, and lots and lots of time. It usually starts with a parent material such as quartz, calcite, or feldspar, which undergoes weathering – the process of disintegration. Weathering can be caused by:

  • Physical factorsTemperature changes, cycles of wetting and drying, and movement of material by wind, water, or gravity
  • Chemical factors – Processes of solution, hydrolysis, oxidation, and many others
  • Living organisms – Bacteria, fungi, earthworms, and even human activity

Weathering of soil makes the parent material disintegrate over time into smaller and smaller pieces. This way, sand, silt, and clay (the core soil ingredients) are created.

Basic types of soil

If you do not consider yourself a pedologist (a soil scientist), you can assume that there are six different types of soil:

  1. Sandy soil – Feels dusty in hand. Sandy soil dries very fast in sunny weather as it does not hold water very well. Escaping water washes away many minerals, so you have to apply some amendments or mulch to give your plants appropriate conditions for growth.
  2. Clay soil – Feels sticky and elastic – a little bit like plasticine. The water doesn't go into it very well because there are not many empty air spaces in the structure of clay soil. It is rich in ingredients, so your plants should freely develop if you maintain sufficient drainage.
  3. Silty soil – An ideal type of soil as it is very rich in ingredients and has excellent properties of holding moisture.
  4. Peaty soil – Feels spongy-like. This type of soil is characterized by outstanding water holding capabilities but also a poor composition of minerals. You should mix it with sources of rich organic matter and care for its pH level (check the following section – soil degradation versus soil conservation).
  5. Chalky soil – Consists of many larger particles – bigger grains and stones. It is alkaline, which means it has a high pH level. Because of that, you should use some acidic fertilizer to ensure the best growth for your plants.
  6. Loamy soil – The best type of soil a gardener can dream of! It is very rich in ingredients, it holds water very well, and its structure ensures good drainage. These perfect properties are caused by well-balanced sand, clay, and silt composition.

Soil degradation versus soil conservation

Soil degradation is the soil process most feared by farmers and gardeners alike. The soil loses its cultivating capabilities by weakening the structure and washing out the rich ingredients. There are several mechanisms of soil degradation:

  • Soil acidification – pH level of the soil drops too much, and it becomes too acidic for plants to grow.
  • Soil salinization – Excessive salt accumulation also inhibits the growth of plants.
  • Soil contamination – Soil is exposed to human-produced waste or other toxic materials. The microorganisms living in soil can assimilate waste material to some extent, but sometimes it is just too much…
  • Desertification – Cultivated land transforms into a desert.
  • Erosion – Physical forces such as water, wind, or a drop in temperature cause the weathering of the soil (go back to the What is soil? - Soil definition section), and then transport it away from its original place, e.g., a gale-like wind moving vast masses of dry topsoil.

To prevent soil degradation and keep it in good condition, you should care about the soil in your garden, yard or field just as much as you care for your plants or grass. Maintaining the quality of your soil is called soil conservation.

If your soil is too alkaline, you can use sulfur or aluminum sulfate to make it more acidic. The other way around, if your soil is too acidic, apply ground lime. It will balance the pH level of your garden soil by making it more alkaline. Make sure that your soil has enough water. You can use some irrigation systems to ensure that your garden soil receives a regular water supply.

Check whether your soil has enough nitrogen, phosphorus, and potassium, as they are essential for growing plants. If there is a nutrient deficiency, use fertilizers or mulch to enrich it. Finally, another way of soil conservation is to protect it from physical forces. You may surround your yard with trees and bushes that will keep the wind away.

FAQ

How do I calculate unit weight of soil?

To determine the unit weight of soil:

  1. Find the total weight of soil.
  2. Divide by the total volume of soil.
  3. That will give you the weight per unit volume. Feel free to use whatever units for weight and volume you feel most comfortable with.

How do I calculate soil volume in raised beds?

To find the volume of soil required for your raised beds:

  1. Measure the width, length, and depth of the raised beds.
  2. Multiply the width, length, and depth together.
  3. The number you get will be the volume of soil you need to fill your raised beds.

How many bags of topsoil in a yard?

36 bags if the bag size is 0.75 cubic feet and 27 bags for the larger 1 cu ft bag. These figures come from the fact there are 27 cu ft in 1 cubic yard: 3 feet in a yard; cubing 3 gives 27.

How much area does a ton of topsoil cover?

The answer will depend on the density of the topsoil and its water content. Taking the density to be 100 lb/ft³ (1602 kg/m³) and you want the topsoil to be 10 inches (25 cm) deep, a ton would cover an area of 24 cubic feet (2.2 m²).

Kacper Pawlik, MD and Bogna Szyk
How much soil do you need?
Length
ft
Width
ft
Depth
in
Area
ft²
Volume needed
cu yd
Density
lb/cu ft
Weight needed
US ton
How much will the soil cost you?
Price per unit mass
$/
US ton
Price per unit volume
$/
cu yd
Total cost
$
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