Measure the area and choose a depth

Start with the footprint you actually intend to fill, measured in feet or meters. For a rectangle, multiply length by width; for more than one bed or patch, measure each separately and add the areas. Keep the measurement level and consistent, and note any parts you are leaving unfilled.

Depth is a separate input you select, not something the calculator derives. Decide the depth from your own plan and the material you are buying, then enter it in inches or centimeters. The tool multiplies area by depth to produce a volume. That number is geometry: it says how much space the layer occupies, not how good the soil is or what it contains.

  1. Measure each area's length and width and record the units.
  2. Add the areas of matching footprints to get a total footprint.
  3. Choose a fill depth and enter it in the same unit system.
  4. Check the displayed volume before moving to bags or bulk ordering.

Source context: University of Maryland Extension · University of Maryland Extension

Convert volume to bags and bulk orders

Bag quantities depend on the volume printed on each package label, so enter that label figure rather than assuming a standard size. The calculator divides the total volume by the bag volume and reports whole bags, because you cannot buy a fraction of a bag. Package label units govern the conversion, so keep bag units consistent with the volume units you entered.

For bulk delivery, enter the supplier's order increment, such as a half cubic yard, and the tool rounds the volume up to the next whole increment. An allowance field lets you add a margin you decide on, and the result is shown with the allowance applied. The rounded order is a purchasing figure, not a prediction of settling, compaction or waste. Metric conversion is available if you measured in one system and buy in another.

  1. Read the bag volume from the package label and enter it.
  2. Enter the supplier's bulk order increment if you are ordering loose material.
  3. Add an allowance only if you have a reason for one, and note it.
  4. Review the whole-bag count and rounded bulk quantity separately.

Source context: University of Maryland Extension

Save, share and carry footprints forward

You can export the inputs and results as a CSV and print the current calculation for your records or a supplier quote. Shared inputs let someone else open the same measured area, depth and quantity settings. These features record what you entered; they do not verify the measurements.

The calculator can carry measured footprints for up to 12 matching areas into the raised-bed planner. Those beds start empty, so the planner receives the footprint geometry only. Fill depth and soil suitability stay with this calculator and are not copied across as crop layout or crop advice. A generic grid is a planning aid, not a recommendation for how to arrange any particular crop.

  1. Export a CSV or print the calculation before ordering.
  2. Use shared inputs when another person needs the same figures.
  3. Carry matching footprints to the raised-bed planner and confirm the beds arrive empty.
  4. Re-enter depth and material decisions in the planner rather than assuming they transferred.

Source context: University of Maryland Extension

Check the site and the material before ordering

Choose a level, draining growing site and assess the existing soil before ordering new material. A soil test guides nutrient and amendment decisions; a geometric volume does not establish soil quality. If you are filling raised beds, bed width, access and the soil underneath affect the design, and roots in an open-bottom bed may continue into the soil below.

Depth advice differs for beds over hard surfaces, and frame height should not be treated as total root depth. Compost-to-topsoil blends of 1:2 or 1:1 are described as options, not a substitute for assessing the materials you actually buy. Confirm composition and weight with the supplier separately, since this tool does not infer density or tons from volume.

  1. Check drainage and level ground at the intended site.
  2. Test existing soil before deciding on amendments.
  3. Confirm bed width, access and what lies beneath an open-bottom bed.
  4. Ask the supplier about composition and weight rather than deriving them from volume.

Source context: University of Maryland Extension · University of Maryland Extension

A worked planning example

Check your measured example

Topsoil ordering geometry only: 12 × 8 ft area at a selected 3 in depth, no allowance; supplier delivery increment 0.5 cu yd. No weight or soil-quality claim.

QuantityCalculated result
volume cuft24
volume cuyd0.8889
rounded bulk order cuyd1

The worked example is ordering geometry only: a 12 by 8 foot area at a selected 3 inch depth with no allowance gives 24 cubic feet, about 0.889 cubic yards, and a supplier increment of 0.5 cubic yard rounds the bulk order to 1 cubic yard. It makes no weight or soil-quality claim, and the figures are not a recommendation for any crop or site.

Example inputs explain the method. Review the source context, chosen cultivar and actual site before planting or ordering.

Your before-you-plant checklist

  • Each measured area and its units are recorded.
  • Selected depth is entered separately from area.
  • Bag volume comes from the package label.
  • Bulk increment and any allowance are noted.
  • CSV or print output is saved before ordering.
  • Site drainage and existing soil have been assessed.

Questions that come up while planning

Does the calculator tell me how many tons of topsoil to order?

No. It reports geometric volume, whole bags and a rounded bulk quantity. It does not infer density, weight or tons from volume, so ask the supplier for weight information.

Why does the bulk order differ from the calculated volume?

Bulk material is rounded up to the supplier's order increment you enter. The rounded figure is the next purchasable increment, not a prediction of settling or waste.

Are the footprints carried to the raised-bed planner filled with soil advice?

No. Up to 12 matching areas transfer as empty beds. Fill depth and soil suitability remain separate and are not copied as crop layout or crop advice.

Sources & method

Horticultural guidance is linked to its original source and regional context. Geometry and unit conversions are calculated separately. Read how we prepare and check a page.