Convert cubic feet (volume) to linear feet (length) when you know the cross-section dimensions. Essential for concrete pours, soil and mulch calculations, lumber estimating, and dumpster sizing. Enter the volume in cubic feet along with the material width and thickness to find the equivalent linear footage.
Cubic Feet to Linear Feet
1 cubic yard = 27 cubic feet. Use either field.
For inches, divide by 12 (e.g. 4" = 0.333 ft)
When This Conversion Applies: Real-World Use Cases
Converting cubic feet to linear feet requires knowing the cross-section. Here are the scenarios where this calculation is critical.
Concrete Pours: From Cubic Yards to Form Length
Concrete is ordered by the cubic yard (27 CF), but you need to know how many linear feet of forms to build. For a 4" thick, 4′ wide sidewalk: 1 CY = 27 / (4 × 0.333) = 20.3 LF of sidewalk. You need 40.6 LF of form boards (both sides). For a 6" thick, 18" wide footing: 1 CY = 27 / (1.5 × 0.5) = 36 LF. The thinner and narrower the pour, the more linear feet you get per cubic yard.
Lumber: Board Feet vs. Cubic Feet vs. Linear Feet
Hardwood lumber is sold by the board foot, softwood construction lumber by the linear foot. 1 cubic foot = 12 board feet. If you have a stack of rough-sawn oak containing 40 cubic feet and each board is roughly 1" thick and 8" wide: cross-section = 1/12 × 8/12 = 0.0556 sq ft. LF = 40 / 0.0556 = 720 LF of boards. But since boards aren't one continuous piece, this tells you total linear footage across all boards in the stack. Divide by average board length (8′) to estimate number of boards: ~90 boards.
Soil, Mulch & Landscaping: Bulk Material to Bed Length
Bulk soil and mulch are sold by the cubic yard. To figure out how many linear feet of garden bed you can fill: if you have 3 CY (81 CF) of garden soil and want beds 3′ wide and 1′ deep: LF = 81 / (3 × 1) = 27 LF of beds. That's 3 beds at 9 feet each, or 4 beds at 6.75 feet. Important: soil compacts 20–30% after watering. 27 LF of freshly filled beds will settle to about 21.6 LF of "full" bed depth after compaction, meaning you need about 25% more soil than the raw calculation suggests.
Dumpster & Waste Sizing
Dumpsters are sized by cubic yards (10, 20, 30, 40 CY). To estimate how many linear feet of material a dumpster can hold: a 20 CY dumpster = 540 CF. If you're disposing of 2×4 lumber that's stacked roughly 4′ wide and 3′ high (the dumpster cross-section): LF = 540 / (4 × 3) = 45 LF of dumpster length that can hold 2×4s stacked to 3′. This helps you estimate: "Can I fit my 100 LF of old deck joists in a 20-yard dumpster?" About 45 LF fill length suggests yes, if stacked efficiently.
Common Dimensions Reference: Cubic Yards to Linear Feet
Quick lookup for the most common concrete, soil, and material cross-sections. 1 cubic yard = 27 cubic feet.
| Application | Width (ft) | Thickness (in / ft) | 1 CY = LF | 3 CY = LF | 5 CY = LF |
|---|---|---|---|---|---|
| Sidewalk (4" thick, 4' wide) | 4.0 | 4" / 0.333 ft | 20.3 LF | 60.8 LF | 101.3 LF |
| Walkway (4" thick, 3' wide) | 3.0 | 4" / 0.333 ft | 27.0 LF | 81.1 LF | 135.1 LF |
| Patio (4" thick, full width) | (varies) | 4" / 0.333 ft | - | 1 CY covers 81 SF at 4" | 5 CY covers 405 SF at 4" |
| Footing (6" thick, 2' wide) | 2.0 | 6" / 0.5 ft | 27.0 LF | 81.0 LF | 135.0 LF |
| Curb (6" thick, 12" wide) | 1.0 | 6" / 0.5 ft | 54.0 LF | 162.0 LF | 270.0 LF |
| Slab (6" thick, full area) | (varies) | 6" / 0.5 ft | - | 1 CY covers 54 SF at 6" | 5 CY covers 270 SF at 6" |
| Garden bed soil (1' deep, 3' wide) | 3.0 | 12" / 1.0 ft | 9.0 LF | 27.0 LF | 45.0 LF |
| Mulch bed (3" deep, 2' wide) | 2.0 | 3" / 0.25 ft | 54.0 LF | 162.0 LF | 270.0 LF |
Worked Examples: Cubic Feet to Linear Feet Calculations
| Scenario | Volume | Width × Thickness | Linear Feet | Practical Takeaway |
|---|---|---|---|---|
| Concrete footing for a 30′ wall | 27 CF (1 CY) | 1′ wide × 1′ thick | 27 LF | 1 CY does exactly 27 LF of 12"×12" footing |
| Garden bed soil for 4 raised beds | 54 CF (2 CY) | 3′ wide × 1.5′ deep | 12 LF | Four 3′-long beds; add 25% for compaction |
| Lumber: rough-sawn stack estimate | 40 CF (480 BF) | Assumed 1" thick × 8" wide avg | ~720 LF total | ~90 boards at 8′ each; useful for pricing estimate |
| Mulch for flower bed border | 18 CF | 2′ wide × 0.25′ (3") deep | 36 LF | Covers 72 sq ft; enough for 36 LF of 2′-wide edging |
Common Mistakes When Converting Cubic Feet to Linear Feet
Mistake #1: Forgetting to Convert All Dimensions to Feet
The formula LF = CF / (Width × Thickness) requires all units in feet. If your width is in inches, divide by 12. If your thickness is in inches, divide by 12. The most common error: plugging "4" for width (thinking 4 feet) and "4" for thickness (thinking 4 inches). If your sidewalk is 4 feet wide and 4 inches thick: thickness in feet = 4/12 = 0.333, NOT 4. The difference: 27 / (4 × 4) = 1.69 LF (wrong) vs. 27 / (4 × 0.333) = 20.3 LF (correct). That's a 12× error.
Mistake #2: Confusing Cubic Feet With Board Feet in Lumber
1 cubic foot of lumber = 12 board feet. If a lumber supplier quotes you "500 board feet of cherry" and you plug 500 into a cubic-feet-to-linear-feet calculator, you're using 12× too much volume. 500 BF = 500/12 = 41.67 cubic feet. At 1" thick and 6" wide: LF = 41.67 / (0.5 × 0.0833) = 41.67 / 0.0417 = 1,000 LF of boards. Using 500 CF would give 12,000 LF — a $5,000–$10,000 mistake.
Mistake #3: Not Accounting for Soil Compaction
Loose soil and mulch contain 15–25% air voids. When you fill a garden bed with 54 CF of loose soil, after the first deep watering it will compact to about 41–46 CF (at 75–85% of loose volume). Your 18 LF bed at 3′ wide and 1′ deep needs: 18 × 3 × 1 = 54 CF of compacted soil. To get that, you need 54 / 0.80 = 68 CF of loose soil (about 2.5 cubic yards). Always order 15–25% more soil than the raw volume calculation suggests.
Mistake #4: Forgetting Concrete Form Boards Need Both Sides
If your calculation says you need 20.3 LF of sidewalk pour, that's the concrete length. The form boards need to go on both sides of the pour, so you need 40.6 LF of form lumber. Plus the ends need to be capped with short form pieces. For a 4-foot-wide pour, add 4 LF of end form per section. Don't forget stakes (about 1 per 2 LF of form = 21 stakes for each 40-foot side). The concrete order is for 1 CY, but the form lumber order is for 45–50 LF of 2×4 stakes and 2× form boards.