Roofing
Roof Pitch Multiplier Chart: Turn a Footprint into Roof Area
Pitch multipliers from 1/12 to 18/12 with roof angles and hip and valley factors. Multiply the footprint by the multiplier to get the real roof area.
By Eren ŞimşirRead guide →
Open-Formula Construction Engineering
Technical guides and transparent formulas for home improvement.
Independent, verified planning articles and material guides by Eren Şimşir. Every calculation is fully exposed with IRC standards, manufacturer tolerances, and real worked examples.
Latest Guides & Analysis
In-depth mathematical breakdowns and buying guides for materials.
Stairs
Stair Rise and Run: Code Limits and Comfortable Dimensions
The IRC allows risers up to 7 3/4 in and treads down to 10 in, but comfortable stairs sit nearer 7 in by 11 in. The rules of thumb, with a chart and an example.
By Eren ŞimşirRead guide →
Deck
How Many Deck Boards Do I Need? Count by Rows, Not Area
Count deck boards row by row: rows from the board width plus gap, boards per row from the board length. Includes a chart of the best board length for each deck size.
By Eren ŞimşirRead guide →
Gravel and sand
How Much Does a Cubic Yard of Gravel Weigh?
A cubic yard of gravel weighs about 1.3 to 1.5 tons. See weights for crushed stone, crusher run, pea gravel, sand and topsoil, and convert yards to tons.
By Eren ŞimşirRead guide →
Drywall
How Many Sheets of Drywall for a 12x12 Room?
A 12x12 room with 8 ft walls takes 12 sheets of 4x8 drywall for the walls and 5 for the ceiling. See counts for 9 and 10 ft walls and 4x12 sheets.
By Eren ŞimşirRead guide →
Flooring
How Many Boxes of Vinyl Plank Flooring Do I Need?
Work out boxes of vinyl plank flooring from your square footage and the coverage on the box, with a chart for common box sizes and a worked example.
By Eren ŞimşirRead guide →
Interactive Calculation Tools
Tested companion utilities designed to execute the formulas outlined in our guides.
You need
1.36 cubic yards
36.67 cu ft including waste
Or in bags
- 123 × 40 lb bags
- 98 × 50 lb bags
- 82 × 60 lb bags
- 62 × 80 lb bags
Outdoor and structure
- Concrete calculatorCubic yards and bag counts for slabs, columns and post holes.
- Gravel calculatorCubic yards, tons and bags of gravel, sand or topsoil for any depth.
- Deck calculatorDeck boards, joists and screws, with real board lengths and offcuts.
- Roofing calculatorRoof area from pitch, squares, shingle bundles and edge trim.
- Fence calculatorPosts, rails, pickets and bags of concrete for a wood fence with gates.
- Brick and block calculatorBricks or concrete blocks and bags of mortar for a wall, plus pavers.
- Mulch calculatorBags or cubic yards of mulch, compost or garden soil for beds and raised beds.
- Stair calculatorRisers, treads and stringer length, checked against IRC limits.
Inside the house
- Tile calculatorTiles and boxes, with grout joint and layout waste.
- Flooring calculatorBoxes of laminate, vinyl plank or wood flooring, plus underlayment.
- Drywall calculatorSheets, screws, joint compound and tape for walls and ceilings.
- Carpet calculatorSquare yards to buy from a 12 ft roll, with seams, pad and tack strip.
- Wallpaper calculatorRolls of wallpaper counted strip by strip, with the pattern repeat.
- Paint calculatorGallons and quarts for walls, ceilings and primer.
Editorial Integrity & Engineering Math
Unlike generic content farms or black-box calculators, every article and tool on Material Guides is governed by verifiable arithmetic, strict peer-reviewed tolerances, and documented construction codes.
- 01
The formula is on the page
Every calculator lists the math it runs, in plain arithmetic you can check with a phone calculator.
- 02
The tables come from the code
Reference tables are generated by the same tested code as the calculator, so the two never disagree.
- 03
Product numbers are labeled
Bag yields and paint coverage come from common US product labels, and you can change them to match yours.
Published by Eren Şimşir
Material Guides is founded and written by Eren Şimşir. Eren holds a B.Sc. in Computer Engineering from Düzce University, is an M.Sc. student in Computer Engineering at Kocaeli University, and is completing a double major in Industrial Engineering.