Material estimator

Bulk Bag Calculator

Estimate bulk bags of gravel, soil, sand, mulch, or aggregate by area, depth, bag volume, weight, and cost.

Reviewed for formula logic and buying assumptions on May 21, 2026.

How This Calculator Works

This bulk bag calculator is for project materials such as gravel, soil, sand, mulch, and aggregate. It estimates how many supplier bulk bags to order from your project area and depth. It is not an FIBC manufacturing calculator; if your supplier lists the bag volume or weight, enter those numbers here.

Formula

Bulk bags = waste-adjusted cubic feet / cubic feet per bulk bag, rounded up. Cubic yards = cubic feet / 27.

Assumptions

The default bulk bag volume is 27 ft^3, or one cubic yard, and the default planning weight is 2,200 lb per bag. Actual bag volume, fill level, moisture, and material density vary by supplier.

Measurement Checklist

Use the supplier's stated bag volume or bag weight instead of assuming every bulk bag is one cubic yard.
Choose the material depth before comparing bag count and delivery cost.
Confirm whether the supplier sells by volume, weight, or a nominal bag size.
Check delivery placement because a full bulk bag may be hard to move once dropped.

Practical Examples

A 12 ft by 10 ft area at 3 inches deep with 10% overage needs 33 ft^3, or 1.22 yd^3. With 27 ft^3 bulk bags, order 2 bags.
A 20 ft by 5 ft path at 3 inches deep with 10% overage needs about 27.5 ft^3, so one 27 ft^3 bulk bag is barely short and two bags is the safer order.
A 12 ft by 16 ft base at 4 inches deep with 10% overage needs about 70.4 ft^3, or 3 one-yard bulk bags.
A 300 sq ft bed refreshed at 2 inches deep with 5% settling needs about 52.5 ft^3, or 2 one-yard bulk bags.

Before You Buy

Buying Guidance

Use the supplier's listed bag volume whenever possible. A one-yard bulk bag is a useful default, but some products are sold in smaller or partially filled bags.
Bulk bags are useful when a full loose delivery is too much material or when the supplier can place bags closer to the work area.
For gravel, sand, and aggregate, confirm whether the bag is sold by volume, weight, or both before comparing suppliers.

Waste Rules

Use 5-10% overage for measured areas and 10-15% when material will settle, compact, or fill irregular edges.
Round up to whole bags. Bulk bags are large enough that one short bag can leave a visible unfinished area.

Common Mistakes

Do not confuse this with an FIBC packaging calculator. This page estimates project material quantity, not bag manufacturing dimensions.
Do not assume every material weighs the same per bag. Wet soil, gravel, sand, mulch, and compost can differ dramatically.

Plan the Rest of the Job

Common Questions

How many cubic feet are in a bulk bag?

It depends on the supplier. Many project-material bulk bags are listed around 1 cubic yard, or 27 ft^3, but some bags are smaller or larger. Use the volume on the product page when available.

How many square feet does a bulk bag cover?

Coverage depends on depth. A 27 ft^3 bulk bag covers about 162 sq ft at 2 inches deep, 108 sq ft at 3 inches deep, or 81 sq ft at 4 inches deep.

Is this the same as an FIBC size calculator?

No. This estimates how many supplier bulk bags of material to order for a project area. FIBC manufacturing calculators size the bag itself for packaging and shipping.

What materials can I use this for?

Use it for gravel, soil, sand, mulch, compost, aggregate, and similar loose materials when the supplier gives a bag volume or bag weight.