The Pentagon Planter Volume calculator computes the volume (V) of a pentagon shaped planter based on the length of the sides (s) and (h) height (see diagram). 
INSTRUCTIONS: Choose units and enter the following:
- (s) Side Length of Pentagon
- (h) Height of planter or desired depth of soil in the planter
Volume (V): The calculator returns the volume in cubic feet. However, this can be automatically converted into other volume units via the pull-down menu next to the answer. The calculator also returns the number of soil bags of the following sizes:
- 1 ft3
- 1.25 ft3
- 2.5 ft3
- 8 quarts
- 32 quarts
- 64 quarts
IMPORTANT NOTE: To compute the amount of soil needed in the planter, use the interior dimensions of the container, and use the top diameter associated with how high you want to fill the container. If you wish to fill to the brim, it is the full inner height.
The Math / Science
The Pentagon Planter Volume calculator computes the volume of a pentagon shaped planter. Enter the length of a side of the planter (s) and the (h) height of the interior of the container (see diagram), then this formula will provide the volume of the container. This answers the following questions:
- How much soil will my hexagon planter hold?
- How much water will my hexagon container hold?
- How much potting soil do I need?
If you do not intend to fill the container to the top, this formula will over estimate unless you use a depth (d) that matches your expected top surface inside the container. Unless it's a very large container, and/or you are only using a small portion of the container, the overage should be small.
Potting Mix and Garden Soil
Potting Mix is combination of organic materials (e.g., peat moss, aged bark and pumice) but no soil (dirt) that is used in lieu of potting soil to improve drainage. Because potting mix has no soil, it tends to be lighter than potting soil and provides a more sterile medium for plants with fewer disease carrying agents. Potting mix is most commonly recommended for plants in containers, and potting mix is particularly desirable for starting seeds. Garden Soil is a gardening product sold that contains natural soil (dirt) comprised of mixture of loam, clay and sand. Garden soil is often used in raised gardens or planters as a healthy and easy medium for plants and seeds on top of the natural soil in one's yard. Garden Soil differs from Potting Mix in that garden soil contains real soil (dirt), where Potting Mix does not.
Potting Mix and Garden Soil Price Survey
vCalc conducts a periodic pricing survey from nationally advertised retailers for various materials. The current Garden Soil Price Survey sample information for Garden Soil and Potting Mix is as follows:
- Date: 5/14/24
- Store: Menards
- Garden Soil (1 ft3): $6.49
- Garden Soil (1.5 ft3): $7.49
- Garden Soil (2 ft3): $9.99
- Potting Mix (1.25 ft3): $13.71
- Potting Mix (2.5 ft3): $27.43
Always use local pricing! There is NO implied guarantee that these prices are available in your area or that products will be available. This pricing is purely provided for estimation convenience.