Put both offers in the same unit
Bag sizes are not all the same. Read the volume on the label, then multiply it by the number of bags you would actually purchase. For example, fourteen 2-cubic-foot bags hold 28 cubic feet, a little more than one cubic yard. Thirteen bags hold only 26 cubic feet.
The calculator rounds bags up because a fractional bag is not normally a purchase option. It prices bulk by the exact estimated volume, so you still need to check minimum orders and sale increments.
Use a worked comparison
Suppose a bed needs 55 cubic feet including your chosen extra allowance. That is 2.037 cubic yards or 28 two-cubic-foot bags. In a purely hypothetical example, bags at $4.50 each total $126. Bulk at $35 per cubic yard plus a $60 delivery fee totals about $131.30 if exact-volume sales are available.
In that example the bags are cheaper, despite bulk having a lower material cost per unit. These are invented comparison prices, not local market quotes. Replace them with prices from your own supplier.
Know what the comparison leaves out
Yard Math's bag comparison assumes you collect the bags without a delivery charge. Bulk includes the delivery or fixed cost you enter. Neither automatically adds sales tax, labor, vehicle costs, or equipment hire. Add these yourself when they change your decision.
Convenience also has value. Bags can be easier to move into several small areas; bulk delivery may suit one large accessible bed. Think about where the truck can unload and how the material will move from the delivery point to the project.
Keep the purchase tied to the project
Save a calculation once its measurements and prices are current. Give it a name such as 'front border, spring refresh' so it is not confused with another estimate. A saved total is still only the cost basis shown; it is not a complete landscaping quote.
If a supplier changes a price, reopen the saved inputs and calculate again. Project entries are snapshots rather than automatically updated prices.
Compare whole bags with an orderable bulk quantity, include delivery, and use actual supplier prices.
Worked examples and sample prices are illustrative, not current supplier quotes. These articles explain quantity arithmetic, not structural or horticultural design. See methodology and limits.