Home/All calculators
All calculators
Every calculator on the site, grouped by section. Each one states its formula, runs a worked example, and says what it does not model. Nothing here is a black box.
Deck calculators
Deck board calculatorCalculate deck board rows, total linear feet, waste allowance and board counts by stock length. Uses actual face width and your real gap, not nominal sizes.
Deck stair calculatorWork out riser count and height, tread depth, total run and stringer length for a deck stair. Checks the result against IRC R311.7 limits and the 2R+T comfort rule.
Deck railing calculatorCalculate railing posts, baluster count and the actual clear opening between balusters. Checks the result against the 4-inch sphere rule before you drill anything.
Deck joist calculatorCalculate how many deck joists you need, the real on-centre spacing, total linear feet, rim joists and blocking rows. Sizing is deliberately left to a span table.
Deck footing calculatorCalculate concrete volume per deck footing and in total, with 60 lb and 80 lb bag counts. Works for round sonotube and augered holes.
Deck cost estimatorEstimate deck cost from area, decking material and build height. See the material breakdown and a separate labor range — and which line drives the total.
Board foot calculatorConvert lumber dimensions into board feet and cost. Uses the T × W × L ÷ 12 formula with thickness and width in inches and length in feet.
Deck square footage calculatorSquare footage, perimeter and the railing run that actually gets built for rectangular and L-shaped decks. Separates floor area from the length that needs a guard.
Baluster spacing calculatorEqual baluster spacing that passes the 4-inch sphere rule, with the real clear opening printed for every bay, plus post width and shrinkage allowance.
Stair stringer calculatorStringer length and cut angle from total rise and run, plus the lumber depth you actually need and how many stringers a given stair width requires.
Deck railing post spacing calculatorDivide a railing run into equal post bays, with corner and end posts counted separately and the real spacing printed for each bay.
Deck skirt calculatorSkirt area and material count for an elevated deck, with ventilation area calculated against the 1:150 rule and the slope allowance most estimates miss.
Ledger fastener count calculatorCount lag or structural screws for a deck ledger from the spacing you supply, with the staggered two-row layout and a box count.
Deck gate calculatorGate opening, frame dimensions, diagonal brace length and board count for a single or double deck gate, with the width limit that stops a gate sagging.
Lumber and materials
Lumber weight calculatorWeight per board and per order from actual dimensions, species density and moisture content. Includes a reference table of densities from cedar to ipe.
Board feet to linear feetConvert board feet to linear feet and back. The conversion only works once you fix the cross-section, so this tool makes you state it and shows both directions.
Plywood sheet calculatorHow many plywood or OSB sheets cover a given area, at 4×8, 4×9, 4×10 or 4×12, with waste and a layer multiplier for double-skin floors.
Deck paint and stain coverageGallons for a deck floor and railing, by coating type and coats, plus primer and realistic coverage for weathered or porous wood.
Framing and structure
Outdoor and landscape
Pergola rafter calculatorRafter count, length with overhang, total linear feet and the shade percentage your spacing actually produces. Posts and beams counted, sizing left to the tables.
Patio paver calculatorPaver count, loose base volume, sand and edge restraint for a patio. Base is ordered loose to compact, so the volume is larger than the finished depth.
Fence post and picket calculatorPosts, rail linear feet, picket count and concrete per hole for a fence run. Enter length, spacing, height and picket width; get quantities, not guesses.
Privacy screen calculatorBoards for a slatted privacy screen: count, linear feet, actual gap and the percentage of the screen that is closed, for horizontal or vertical slats.
Deck lighting and voltage dropTotal load, current and voltage drop for 12 or 24 V deck lighting, with the maximum run per wire gauge and a gauge that reaches the last fixture.
Mulch calculatorHow much mulch a bed needs in cubic yards and bags, with depth guidance by bed type and the settlement allowance most estimates leave out.
Topsoil calculatorTopsoil volume from area and depth, converted to cubic yards, tons and bags, with the compaction factor that makes delivered soil arrive short.
Sod calculatorSod quantity from area, with roll and pallet counts, an allowance for cutting around edges, and the installation window that decides whether it survives.
Retaining wall calculatorSegment blocks, caps and base gravel for a block retaining wall, with the height limit above which a wall needs an engineer rather than a calculator.
Fire pit calculatorBlocks or bricks for a round fire pit, the inner diameter you actually get, and the clearance to combustibles that decides whether it is safe where you put it.
Patio base calculatorCrushed aggregate and bedding sand for a paver patio, with loose-versus-compacted depths and the excavation volume that has to be removed first.
Pergola shade calculatorHow much shade a pergola actually provides, from rafter width, spacing and sun angle. Includes why the noon number is not the number that matters.
Gravel calculatorCubic yards and tons of gravel for a driveway, path or drainage bed, with density by aggregate type and the waste allowance to order with.
Fence picket calculatorPicket, post and rail counts for a fence run, with the gap width that decides the picket count and the post spacing that decides everything else.
How to use these together
They are designed to be used in build order. Size the footings first, because frost depth constrains where posts can go. Then lay out joists, which sets the post count. Then decking, which depends on joist spacing. Railing and stairs come last, and both are priced linearly rather than by area — which is why a cost estimate that works only in square feet will miss the largest line on a raised deck.
Questions people actually ask
Are all the calculators free?
Yes. No account, no limit, no paywall. The site is funded by advertising, disclosed on the affiliate disclosure page, and no advertiser has input into a formula.
Which calculator should I start with?
The one that matches the decision in front of you. If you are ordering material, start with boards. If you are framing, start with joists. If you are budgeting, start with cost and work backwards.
Why do some tools refuse to give a structural answer?
Because joist depth, beam size and footing diameter depend on species, grade, load and soil — five variables that a web form cannot responsibly combine. Those tools count and lay out; the sizing goes to a span table or an engineer.