Formula
Cubic yards = length ft × width ft × (depth inches ÷ 12) ÷ 27. Planning cubic yards = cubic yards × (1 + allowance percent ÷ 100).
Cubic Yards Calculator
Calculate cubic yards from length, width and depth in feet and inches, with measured cubic feet, cubic metres, ordering allowance, rounded order quantity and a printable concrete, gravel, soil, mulch or classroom job note.
Worked example
For 12 ft × 10 ft × 4 in: depth in feet = 4 ÷ 12 = 0.3333 ft. Cubic feet = 12 × 10 × 0.3333 = 40 ft³. Cubic yards = 40 ÷ 27 = 1.4815 yd³. With 10% allowance, planning quantity = 1.4815 × 1.10 = 1.6296 yd³.
Professional note
Master’s Tip: measure the depth in several spots and write the allowance reason on the report. A neat cubic-yard number is less useful than a record that says whether extra quantity covers compaction, uneven grade, forms, spillage or supplier rounding.
Regional and unit assumptions
Standard or basis: US customary volume relationship, where 1 yard = 3 feet and therefore 1 cubic yard = 27 cubic feet. The page uses arithmetic only and does not approve structural concrete, soil compaction, drainage or code requirements.
Assumptions and limitations
- The measured shape is a rectangular prism: length and width in feet, depth in inches.
- One cubic yard equals 27 cubic feet.
- The allowance is a planning buffer for site variation, compaction, waste or supplier rounding; it is not part of the exact measured volume.
- Concrete, gravel, soil and mulch may also need density, bag size, truck minimums, mix design or local supplier advice before ordering.
Methodology & Accuracy
How this calculator is checked
CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.
Formula used
Cubic yards = length ft × width ft × (depth inches ÷ 12) ÷ 27. Planning cubic yards = cubic yards × (1 + allowance percent ÷ 100).
Standard or basis
Standard or basis: US customary volume relationship, where 1 yard = 3 feet and therefore 1 cubic yard = 27 cubic feet. The page uses arithmetic only and does not approve structural concrete, soil compaction, drainage or code requirements.
Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.Master's Tip
Master’s Tip: measure the depth in several spots and write the allowance reason on the report. A neat cubic-yard number is less useful than a record that says whether extra quantity covers compaction, uneven grade, forms, spillage or supplier rounding.
Related calculators
Questions
How do you calculate cubic yards?
Multiply length in feet by width in feet by depth in feet to get cubic feet, then divide by 27 because one cubic yard contains 27 cubic feet.
How do I use inches for depth?
Convert inches to feet first by dividing by 12. A 4-inch depth is 4 ÷ 12 = 0.3333 feet.
Should I add extra cubic yards when ordering?
Often yes, but keep it separate from the exact measured volume. Extra quantity may cover compaction, uneven ground, waste, spillage or supplier rounding.
Is this the same as a concrete calculator?
It uses the same rectangular-volume arithmetic, but concrete jobs may also need mix design, reinforcement, forms, delivery minimums and structural approval.
Can I use this for gravel, soil or mulch?
Yes for first-pass rectangular volume in cubic yards. For weight, bags or truck loads, check material density, compaction and supplier units separately.
Calculation note
Cubic yards are common in North American construction and landscaping because bulk materials are often sold by volume. A cubic-yard calculator turns tape-measure dimensions into a quantity that can be checked on a quote, delivery ticket or classroom worksheet.
A cubic yard is a volume cube
A yard is three feet long, so a cube one yard on each side is 3 ft × 3 ft × 3 ft, or 27 cubic feet. That fixed relationship is the reason rectangular job measurements in feet can be divided by 27 to get cubic yards.
Depth is the usual mistake
Lengths and widths are commonly measured in feet, while slab, gravel and mulch depths are often given in inches. Converting depth to feet before multiplying prevents a 12-times error.
The printout is a job record, not just an answer
For ordering material, the useful record includes measured length, width, depth, exact volume, allowance percent, formula, date/page context and a notes area for supplier rounding or site conditions.
Sources and further readingNIST Handbook 44 Appendix C: General Tables of Units of MeasurementBritannica: Volume