DIY Project Calculators
Behind the numbers

Methodology

Start with your measurements. Keep the assumptions visible.

Choosing the formula

Rectangular volume is length × width × depth. Round shapes use the area of a circle multiplied by depth. Material counts divide that volume or area by the selected product's yield or coverage.

A formula describes the geometry. It does not select a safe structural design, soil depth or wall height for your project.

Units and conversions

The calculators store lengths in feet and volumes in cubic feet, then convert input and output for imperial or metric units. Geometry gives the yard, square-foot and cubic-foot conversions. The source register below records the independently sourced metric and weight definitions.

US tons mean short tons. Metric tonnes are a different unit. Material density estimates must use the same volume and weight units as the calculation.

Rounding and waste

Bag, block, board, sheet and piece counts round up after waste is applied. A small tolerance prevents floating-point noise from adding an extra piece. Displayed volume and weight values use the precision recorded below; the calculation keeps its full precision until the final count.

Waste defaults are planning choices, not manufacturer requirements. They remain editable. Measurement and conversion tools, topsoil, pea gravel, board foot and linear feet have no waste allowance. Decking and retaining-wall waste start at zero so their supplied worked examples are preserved.

Tests on each build

The build runs the available calculation tests before producing the website. Each calculator is added with tests for its worked example and relevant edge cases. Unit changes must preserve the physical measurement, and invalid dimensions must not produce a result.

Report a problem

Send the tool URL, measurements and unit system using the details on the contact page. See the editorial standards for the correction policy.

Sources and constant register

This register includes the shared unit definitions and the material values the tools use. A supplied source link is not a claim that its value has been independently confirmed. Where a source is missing, the gap remains visible.

QUIKRETE Concrete Mix yields; other products differ — check your bag.

Densities are a typical range — ask your supplier. Weight varies with moisture and gradation.

Values marked with a link come from the linked source, which opens in a new tab. Unit conversions and our own defaults are listed separately.

Where the numbers come from 41

Meters per international foot
0.3048 m/ft
NIST, international foot conversion (opens in a new tab)nist.gov
Accessed
Kilograms per pound
0.45359237 kg/lb
NIST Guide to the SI, pound conversion; exact definition (opens in a new tab)nist.gov
Accessed
Pounds per US short ton
2000 lb/US ton
NIST Guide to the SI, US short ton (2000 lb) (opens in a new tab)nist.gov
Accessed
Kilograms per metric tonne
1000 kg/tonne
NIST Guide to the SI, tonne (opens in a new tab)nist.gov
Accessed
Cubic inches per board foot
144 cu in/board ft
University of Wisconsin–Madison Extension, Forestry Facts No. 42, What Is A Board Foot? (opens in a new tab)forestry.extension.wisc.edu · PDF
Accessed
80 lb concrete bag yield
0.6 cu ft/bag
QUIKRETE Concrete Mix No. 1101 data sheet (revised October 2022) (opens in a new tab)quikrete.com · PDF
Accessed
60 lb concrete bag yield
0.45 cu ft/bag
QUIKRETE Concrete Mix No. 1101 data sheet (revised October 2022) (opens in a new tab)quikrete.com · PDF
Accessed
50 lb concrete bag yield
0.375 cu ft/bag
QUIKRETE Concrete Mix No. 1101 data sheet (revised October 2022) (opens in a new tab)quikrete.com · PDF
Accessed
40 lb concrete bag yield
0.3 cu ft/bag
QUIKRETE Concrete Mix No. 1101 data sheet (revised October 2022) (opens in a new tab)quikrete.com · PDF
Accessed
90 lb concrete bag yield
0.675 cu ft/bag
QUIKRETE Concrete Mix No. 1101 data sheet (revised October 2022) (opens in a new tab)quikrete.com · PDF
Accessed
Concrete bag sizes offered
40, 50, 60, 80, 90 lb
QUIKRETE Concrete Mix No. 1101 data sheet (revised October 2022) (opens in a new tab)quikrete.com · PDF
Accessed
Standard 8 × 8 × 16 block count per wall area
1.125 blocks/sq ft
Titan America Block Estimating Guide, as supplied (opens in a new tab)titanamerica.com · PDF
Accessed · Source and value supplied in the owner brief
Wall area per standard block, including joint
≈ 0.888889 sq ft/block
Derived: reciprocal of 1.125 blocks per square foot; display ≈ 0.889 (opens in a new tab)titanamerica.com · PDF
Accessed · Source and value supplied in the owner brief
Joint assumed by the standard block estimate
0.375 in
Owner brief: 3/8 inch joint assumption in supplied estimating guide (opens in a new tab)titanamerica.com · PDF
Accessed · Source and value supplied in the owner brief
Gravel / crushed stone density range
1.4 – 1.7 US tons/cu yd
Typical range; no primary standard exists, and weight varies with moisture and gradation. Confirm with your supplier.
Accessed · Source and value supplied in the owner brief
Dry sand density range
1.3 – 1.5 US tons/cu yd
Typical range; no primary standard exists, and weight varies with moisture and gradation. Confirm with your supplier.
Accessed · Source and value supplied in the owner brief
Wet sand density range
1.5 – 1.7 US tons/cu yd
Typical range; no primary standard exists, and weight varies with moisture and gradation. Confirm with your supplier.
Accessed · Source and value supplied in the owner brief
Dry soil / topsoil density range
1 – 1.3 US tons/cu yd
Typical range; no primary standard exists, and weight varies with moisture and gradation. Confirm with your supplier.
Accessed · Source and value supplied in the owner brief
Dry fill dirt density range
1 – 1.3 US tons/cu yd
Typical range; no primary standard exists, and weight varies with moisture and gradation. Confirm with your supplier.
Accessed · Source and value supplied in the owner brief
Mulch density range
0.2 – 0.4 US tons/cu yd
Typical range; no primary standard exists, and weight varies with moisture and gradation. Confirm with your supplier.
Accessed · Source and value supplied in the owner brief
Composite deck side gap
0.1875 in
Trex, How to Space Deck Boards (opens in a new tab)trex.com
Accessed
Editable deck board actual width default
5.5 in
Southern Pine Inspection Bureau, Nominal vs actual lumber sizes (cites PS 20-20) (opens in a new tab)blog.spib.org
Accessed
Selectable topsoil bag sizes
0.75, 1, 1.25, 1.5, 2 cu ft/bag
Common retail bag sizes (Texas A&M AgriLife Extension lists 0.75, 1, 1.25 and 2 cu ft; 1.5 cu ft is a common size for bagged garden soil). Check your bag. (opens in a new tab)travis-tx.tamu.edu
Accessed · Source and value supplied in the owner brief
Actual side of a nominal 4 × 4 post
3.5 in
Southern Pine Inspection Bureau, Nominal vs actual lumber sizes (cites PS 20-20) (opens in a new tab)blog.spib.org
Accessed
Standard block nominal module
8, 8, 16 in thickness, in height, in width
Owner specified 8 × 8 × 16 nominal block; standard face module includes joints (opens in a new tab)titanamerica.com · PDF
Accessed · Source and value supplied in the owner brief
80 lb Concrete Mix bags per pallet
42 bags/pallet
QUIKRETE Concrete Mix retail page (Lowe's), product 1101: "42 per pallet (SKU #10385)" (opens in a new tab)quikrete.com
Accessed · Source and value supplied in the owner brief
60 lb Concrete Mix bags per pallet
56 bags/pallet
QUIKRETE Concrete Mix retail page (Lowe's), product 1101: "56 per pallet (SKU #10387)" (opens in a new tab)quikrete.com
Accessed · Source and value supplied in the owner brief
40 lb Concrete Mix bags per pallet
80 bags/pallet
QUIKRETE Concrete Mix retail page (Lowe's), product 1101: "80 per pallet (SKU #4030)" (opens in a new tab)quikrete.com
Accessed · Source and value supplied in the owner brief
Fence post hole diameter, times the post width
3 × post width
QUIKRETE Concrete Mix No. 1101 data sheet (revised October 2022): "about 3 times the diameter of the post" (opens in a new tab)quikrete.com · PDF
Accessed · Source and value supplied in the owner brief
Fence post hole depth, share of the post length
≈ 0.333333 of post length
QUIKRETE Concrete Mix No. 1101 data sheet (revised October 2022): "Hole depth should be 1/3 the overall post height" (opens in a new tab)quikrete.com · PDF
Accessed · Source and value supplied in the owner brief
Dry mix under a fence post
6 in
QUIKRETE Concrete Mix No. 1101 data sheet (revised October 2022): "Place 6 in (150 mm) of dry concrete mix in the bottom of the hole" (opens in a new tab)quikrete.com · PDF
Accessed · Source and value supplied in the owner brief
Pounds per cubic foot for 1 g/cm³
62.4 lb/ft³ per g/cm³
Cornell Soil Health Lab, Fact Sheet 22-17, Soil Bulk Density (February 2022): "1 g/cm3 = 62.4 lb/ft3" (opens in a new tab)soilhealthlab.cals.cornell.edu · PDF
Accessed · Source and value supplied in the owner brief
Loose gravel, common figure
1.4 US tons/cu yd
FEMA appeal 219532, Road Repair (29 February 2012), citing a pocket reference and a quarry manager, for uncompacted dry aggregate (opens in a new tab)fema.gov
Accessed · Source and value supplied in the owner brief
Loose dry aggregate, tested
112 lb/ft³
FEMA appeal 219532, Road Repair (29 February 2012): tests conducted by IDOT, reported by the quarry manager (opens in a new tab)fema.gov
Accessed · Source and value supplied in the owner brief
Compacted Class A crushed stone
140 lb/ft³
Iowa DOT Design Manual, as recorded in FEMA appeal 219532, Road Repair (29 February 2012) (opens in a new tab)fema.gov
Accessed · Source and value supplied in the owner brief
Liters per US gallon
3.785412 L/gal
NIST Guide to the SI (SP 811), Appendix B.8, gallon (U.S.) (opens in a new tab)nist.gov
Accessed · Source and value supplied in the owner brief
Square feet per acre
43560 sq ft/acre
NIST, revised unit conversion factors (international foot, from 2023): "43,560 ft2 = 10 ch2 = 160 rd2" (opens in a new tab)nist.gov
Accessed · Source and value supplied in the owner brief
Square meters per acre
≈ 4046.86 m²/acre
NIST, revised unit conversion factors (international foot, from 2023): "4046.856 422 4 m2" (opens in a new tab)nist.gov
Accessed · Source and value supplied in the owner brief
Play sand bag volume (50 lb)
0.5 cu ft/bag
QUIKRETE Play Sand No. 1113 tear pad: "Contains approx. ½ cubic foot (14 L) of Play Sand" (opens in a new tab)quikrete.com · PDF
Accessed · Source and value supplied in the owner brief
Play sand bag weight
50 lb
QUIKRETE Play Sand No. 1113 tear pad: "Contains approx. ½ cubic foot (14 L) of Play Sand" (opens in a new tab)quikrete.com · PDF
Accessed · Source and value supplied in the owner brief
Common mulch bag sizes
0.75, 1, 1.25, 2 cu ft/bag
Common sizes — check your bag. Texas A&M AgriLife Extension, Travis County, “How Much Compost, Soil or Mulch?” lists 0.75, 1, 1.25 and 2 cu ft bags (opens in a new tab)travis-tx.tamu.edu
Accessed · Source and value supplied in the owner brief
Unit definitions and geometry13
Inches per foot
12 in/ft
Unit definition: one foot contains twelve inches
Feet per yard
3 ft/yd
Unit definition: one yard contains three feet
Cubic feet per cubic yard
27 cu ft/cu yd
Geometry: 3 × 3 × 3 feet
Square inches per square foot
144 sq in/sq ft
Geometry: 12 × 12 inches
Cubic inches per cubic foot
1728 cu in/cu ft
Geometry: 12 × 12 × 12 inches
Liters per cubic meter
1000 L/m³
Metric definition: one liter is one cubic decimeter
Centimeters per meter
100 cm/m
Metric prefix definition: centi is one hundredth
Percent denominator
100 %
Definition of percent: parts per hundred
Circle constant π
≈ 3.14159 unitless
Circle geometry, as specified in the owner brief
Area of a 4 × 8 ft sheet
32 sq ft
Geometry: 4 × 8 feet
Area of a 4 × 10 ft sheet
40 sq ft
Geometry: 4 × 10 feet
Inside corners in a rectangular room
4 corners/room
Geometry: a rectangle has four corners
Square yards per acre
4840 sq yd/acre
Derived: 43,560 sq ft ÷ 9 sq ft per square yard
Our defaults and starting values60
Count rounding tolerance
1e-9 unitless
Owner specification: ceil(x − 1e-9)
Volume and weight display precision
2 decimal places
Owner specification: display volume and tons to two decimals
Bag concrete waste default
10 %
Owner planning default; editable
Concrete block waste default
5 %
Owner planning default; editable
Plywood waste default
10 %
Owner planning default; editable
Baseboard waste default
10 %
Owner planning default; editable
Deck board waste default
0 %
Owner build choice preserves the worked example; editable
Retaining wall waste default
0 %
Owner build choice preserves the worked example; editable
Bag calculator starting slab dimensions
10, 10, 4 ft length, ft width, in depth
Owner worked example; editable starting measurements, not a recommended pour
Bag calculator starting bag size
80 lb
Owner worked example; editable selection
Round-shape starting diameter
10 in
Owner fence-post example; editable starting measurement, not a hole-size recommendation
Block calculator starting wall dimensions
20, 6 ft length, ft height
Owner worked example; editable starting measurements
Cubic yard calculator starting dimensions
12, 10, 3 ft length, ft width, in depth
Owner worked example; editable starting measurements
Weight converter starting volume
3 cu yd
Owner worked example; editable starting volume
Concrete depth unit-check threshold
12 in
Owner specified unit-check warning, not a structural depth limit
Cubic yard depth unit-check threshold
24 in
Owner specified unit-check warning, not a recommended depth
Ready-mix comparison prompt threshold
1 cu yd
Owner planning prompt: compare delivery above about one cubic yard
Topsoil calculator starting dimensions
4, 8, 12 ft length, ft width, in depth
Owner worked example; editable starting measurements, not a recommended soil depth
Topsoil calculator starting bag size
1.5 cu ft/bag
Owner worked example; editable selection
Topsoil depth unit-check threshold
24 in
Owner specified unit-check warning, not a recommended depth
Pea gravel calculator starting dimensions
10, 10, 3 ft length, ft width, in depth
Owner worked example; editable starting measurements
Pea gravel circle starting diameter
10 ft
Build choice: matches the starting length; editable, not a recommended size
Site build choice, not a sourced product value
Pea gravel path depth hint
2 – 3 in
Owner brief: hint text only, not a sourced rule
Pea gravel depth unit-check threshold
12 in
Owner specified unit-check warning, not a recommended depth
Retaining wall starting dimensions
30, 3 ft length, ft height
Owner worked example; editable starting measurements, not a recommended wall height
Retaining wall starting block face
18, 6 in width, in height
Owner worked example; brands vary, so enter your block face
Retaining wall starting cap length
18 in
Build choice: matches the starting face width; enter your cap length
Site build choice, not a sourced product value
Block face unit-check range
2 – 36 in
Build choice: face sizes outside this range prompt a unit check; not a product range
Site build choice, not a sourced product value
Deck board calculator starting dimensions
12, 12 ft run, ft width
Owner worked example; editable starting measurements
Deck board lengths offered
12, 16, 20 ft
Owner specification; editable selection
Deck board calculator starting board length
12 ft
Owner worked example; editable selection
Board foot calculator starting piece
2, 6, 8 in thickness, in width, ft length
Owner worked example; editable starting measurements
Plywood calculator starting room
12, 12 ft length, ft width
Owner worked example; editable starting measurements
Linear feet starting pieces and length
8, 10 pieces, ft
Owner worked example; editable starting measurements
Linear feet starting area and board width
100, 6 sq ft, in
Owner worked example; editable starting measurements
Linear feet starting stock length
10 ft
Build choice: matches the starting piece length; enter the length you will buy
Site build choice, not a sourced product value
Baseboard calculator starting room
12, 14 ft length, ft width
Owner worked example; editable starting measurements
Baseboard calculator starting door
1, 3 doors, ft width
Owner worked example; editable, not a standard door width
Baseboard piece lengths offered
8, 12, 16 ft
Owner specification; editable selection
Baseboard calculator starting piece length
8 ft
Owner worked example; editable selection
Mulch calculator starting bag size
2 cu ft/bag
Wave 2 pack default; editable selection
Common drywall sheet lengths
8, 10, 12 ft (4 ft wide)
Common sizes — check your store. A 4 ft wide sheet covers 4 × its length in square feet
Drywall sheet width
4 ft
Common sizes — check your store
Drywall waste default
10 %
Owner planning default; editable
Paver waste default
5 %
Owner planning default; editable
Square footage unit-check threshold
10000 ft
Owner specified unit-check warning, not a size limit
Gravel calculator depth unit-check threshold
12 in
Owner specified unit-check warning, not a recommended depth
Mulch depth unit-check threshold
12 in
Owner specified unit-check warning, not a recommended depth
Square footage calculator starting area
12, 12 ft length, ft width
Wave 2 pack worked example; editable starting measurements
Square feet to acres starting value
10000 sq ft
Wave 2 pack worked example; editable starting measurements
Square feet to acres starting lot
200, 200 ft length, ft width
Wave 2 pack worked example; editable starting measurements
Gravel calculator starting dimensions
10, 10, 4 ft length, ft width, in depth
Wave 2 pack worked example; editable starting measurements
Gravel calculator starting circle diameter
12 ft
Wave 2 pack worked example; editable starting measurements
Mulch calculator starting bed
10, 10, 3 ft length, ft width, in depth
Wave 2 pack worked example; editable starting measurements
Drywall calculator starting room
12, 12, 8 ft length, ft width, ft wall height
Wave 2 pack worked example; editable starting measurements
Paver calculator starting patio
10, 10 ft length, ft width
Wave 2 pack worked example; editable starting measurements
Paver calculator starting paver face
4, 8 in width, in length
Wave 2 pack worked example; measure your own paver
Sand calculator starting area
10, 10, 2 ft length, ft width, in depth
Wave 2 pack worked example; editable starting measurements
Mulch, paver and sand circle starting diameter
10 ft
Build choice: matches the starting length; editable, not a recommended size
Site build choice, not a sourced product value
Rooms that can be added in one estimate
8 rooms
Build choice: keeps the form manageable; run the tool again for more rooms
Site build choice, not a sourced product value
By , DAE in Civil Engineering, three years as a site supervisor.Last updated How we calculate