All Calculators

Guides & how-tos

Renovation guides

Free renovation calculators and how-to guides - work out how much material you need, measure up a room or roof, estimate costs, and choose between options like laminate vs vinyl or sod vs seed. Every guide is paired with a free calculator, so you can run the numbers for your own job in metric or imperial.

Filter

Walls, floors & interior

Interior material calculators - tiling, flooring, paint, wallpaper, drywall and insulation.

Square Metre Area

Open calculator →

How to Calculate Square Footage

The length-times-width method for rooms, walls and irregular shapes, with a room-size table.

How to Calculate the Square Footage of a House

Measure a whole house room by room or from outside, and know what counts as living area.

Square Feet to Square Metres

The square feet to square metres conversion both ways, with a ready-reckoner table.

How Many Square Feet in an Acre?

An acre is 43,560 sq ft - with a fractions-of-an-acre table and how big an acre really is.

Square Feet to Square Yards

Square feet to square yards is a divide-by-9 - with a table and the carpet and concrete context.

How Big Is 1,000 Square Feet?

What 1,000 sq ft looks like - dimensions, metric size and everyday comparisons.

Tile

Open calculator →

How Many Tiles Do I Need?

The formula for tile count, including grout gap, tile size and boxes to buy.

How to Calculate Tile Wastage

The right wastage percentage for each tile layout, and why patterns waste more.

How to Measure a Shower for Tile

Measure shower walls, niche and floor for tile, with the right wastage.

Paint

Open calculator →

How Much Paint Do I Need?

The wall-area formula for paint, with coats, coverage and tins to buy.

How Many Coats of Paint Do I Need?

When one, two or three coats are needed - and when to prime first.

Interior vs Exterior Paint

Durability, additives and coverage differences - and why each belongs where it does.

Wallpaper

Open calculator →

How Much Wallpaper Do I Need?

Count wallpaper in rolls the right way - the drop method, not area.

Understanding Wallpaper Pattern Repeat

What pattern repeat means, straight vs offset match, and its effect on rolls.

Peel-and-Stick vs Traditional Wallpaper

Durability, fitting, removal and cost - peel-and-stick vs paste wallpaper.

Flooring

Open calculator →

How to Measure a Room for Flooring

Step-by-step measuring for floors, including L-shaped rooms and doorways.

How Many Boxes of Flooring Do I Need?

Turn your room size into the right number of boxes, with wastage built in.

Laminate vs Vinyl Plank vs Hardwood Flooring

Cost, durability, water resistance and lifespan compared across the big three floors.

Carpet

Open calculator →

How Much Carpet Do I Need?

Turn your room sizes into the linear yards of broadloom to order, with a 12x12 example.

How Much Does Carpet Cost?

Estimate carpet cost from the quantity - carpet, underlay, gripper, fitting and uplift.

How to Measure Stairs for Carpet

Count the steps, measure the tread and riser, and turn it into a runner length.

Standard Carpet Roll Widths

Standard broadloom roll widths by country, and why the width decides your seams.

How Is Carpet Sold?

Square yards, square feet, square metres and broadloom metres explained, with conversions.

Epoxy Garage Floor Cost

Open calculator →

How Much Does It Cost to Epoxy a Garage Floor?

Estimate the cost to epoxy a garage floor - DIY kits vs a pro install, and what drives the price.

How Much Epoxy Do I Need for a Garage?

Work out the epoxy and number of kits a garage floor needs, from area, coats and kit coverage.

How to Epoxy a Garage Floor

Step-by-step DIY guide to epoxying a garage floor, from slab prep to the final topcoat.

How to Prep a Garage Floor for Epoxy

How to prepare a garage slab for epoxy - clean, etch or grind, moisture-test and repair.

How Long Does an Epoxy Garage Floor Last?

How long an epoxy garage floor lasts, and the few things that decide whether it is 2 years or 20.

Is an Epoxy Garage Floor Worth It?

The real pros, cons and alternatives for an epoxy garage floor, and when it is worth it.

How to Clean an Epoxy Garage Floor

A simple routine for cleaning an epoxy garage floor - dust, oil, tyre marks and winter salt.

Skirting Board

Open calculator →

Baseboard Installation Cost

Material and labor cost per linear foot, plus removal and painting add-ons.

How Much Baseboard Do I Need?

Turn room size or square footage into linear feet of baseboard and lengths to buy.

How Much Crown Molding Do I Need?

Turn room size into linear feet of crown molding and lengths to buy, corners included.

Stud Wall

Open calculator →

How to Build a Stud Wall

Set out and build a timber stud partition, from plates and studs to noggins and boarding.

Cost to Build a Stud Wall

The material breakdown of a stud wall, and DIY vs installed cost per area.

Stud Wall Spacing

When to use 16 in (400 mm) vs 24 in (600 mm) stud centres, and how it changes the count.

Noggins vs Blocking

The horizontal blocks between studs - naming, purpose, and how many rows to fit.

Board Foot & Timber Volume

Open calculator →

Nominal vs Actual Lumber Sizes

The actual size of a 2x4, 2x6, 2x8 and more - full chart in inches and mm.

How to Calculate Board Feet

The board-foot formula, a worked example and the board feet in common boards.

What Is a Board Foot?

A board foot is 144 cubic inches of wood - and how it differs from other feet.

What 4/4, 5/4 and 8/4 Mean (Lumber Thickness)

The hardwood quarter system: 4/4 = 1 in, 5/4 = 1¼, 8/4 = 2, rough vs surfaced.

GIB & Plasterboard

Open calculator →

How Much Drywall Do I Need?

Turn a room size or a square-footage figure into a drywall sheet count.

How Much Drywall Mud and Tape Do I Need?

Work out joint compound and tape from your boarded area, in boxes and rolls.

Cost to Hang and Finish Drywall

Estimate drywall labor and material cost per square foot and per sheet.

Insulation Batts

Open calculator →

How Much Insulation Do I Need?

Turn a wall, attic or floor area into a batt or bag count.

How Much Attic Insulation Do I Need?

Attic R-value by climate zone, the depth it needs, and the bag count.

Blown-In vs Batt Insulation

Batts vs blown-in loose fill compared, with fibreglass vs cellulose.

Insulation R-Value Chart

Pick the right R-value by room and climate, the depth it needs, and US/RSI/U-value conversions.

Outdoor & structures

Outdoor build calculators - decks, fences, patios, stairs, roofing and concrete.

Concrete

Open calculator →

How Many Bags of Concrete Do I Need?

Turn slab or footing volume into a bag count, with yields and the ready-mix threshold.

How Much Concrete for a Fence Post?

Hole sizing, concrete per post and bag count for a fence - with fast-setting tips.

Brick & Block

Open calculator →

How Many Bricks Do I Need?

Turn wall area into a brick count, with tables by wall size and waste.

How Many Bricks Per Square Foot?

Bricks per square foot and per square metre for every common brick size.

How Much Mortar Do I Need?

Mortar bags, sand and cement for brick and block, with the type to use.

How Many Bricks for a Fire Pit?

Bricks per ring and per course for a round fire pit, by diameter.

Standard Brick Sizes

US, UK and Australian brick sizes, with nominal vs actual explained.

Brick Veneer vs Solid Brick

How brick veneer and solid brick differ in structure, cost and count.

Mortar vs Concrete

How mortar, concrete and cement differ, and when to use each.

How Many Bricks for a Patio?

Brick pavers per square foot and by patio size, plus the base.

Reo Bar (Reinforcing)

Open calculator →

How Much Rebar Do I Need?

Turn a slab or footing into bars each way, linear feet, weight and bars to buy.

How Much Rebar Do I Need for a Slab?

Bars each way and linear feet for a concrete slab, with tables by slab size.

How Much Rebar Do I Need for Footings?

Longitudinal bars, ties and lap splices for a strip footing, with a worked example.

Rebar Size Chart

US #-bar and metric rebar sizes with diameter and weight, and what they mean.

How Much Does Rebar Weigh?

Weight per foot and per metre for every rebar size, and the formula behind it.

Rebar Spacing for a Concrete Slab

Typical slab rebar grids, what spacing does, and cover - with a spacing table.

Concrete Block

Open calculator →

How Many Concrete Blocks Do I Need?

Block counts per 100 sq ft, by block size, with the mortar and waste.

Concrete Block Sizes

US CMU sizes (4/6/8/12 in), metric and UK blocks, nominal vs actual.

How Much Does a Concrete Block Weigh?

Block weights by size, hollow vs solid, plus pallet and wall totals.

Decking

Open calculator →

How Many Deck Boards Do I Need?

The formula for deck boards, plus how gaps, board length and joists affect it.

Composite vs Wood Decking

Upfront cost vs lifetime cost, maintenance and lifespan compared.

Paver

Open calculator →

How Many Pavers Do I Need?

Turn a patio area and paver size into a paver count, per m² or per sq ft.

How Much Sand Do I Need for Pavers?

Size the bedding (leveling) sand and the jointing or polymeric sand for pavers.

How Much Does It Cost to Install Pavers?

Estimate paver cost from the material list plus labor - patio or driveway.

Types of Pavers Compared

Concrete, brick and stone pavers, common sizes, and the laying patterns.

Deck Tile

Open calculator →

How Many Deck Tiles Do I Need?

Turn a deck or patio area and tile size into a tile and pack count.

How to Install Deck Tiles

Step-by-step guide to laying interlocking deck tiles, from base prep to edge trim.

Can You Put Deck Tiles on Grass or Dirt?

Whether deck tiles work over grass, dirt or an old deck, and how to prep each base.

Types of Deck Tiles Compared

Composite, wood, plastic and rubber deck tiles compared, with sizes and pack counts.

Fence

Open calculator →

How Many Fence Posts Do I Need?

The spacing rules and formula for counting fence posts, panels and bays.

How Many Fence Pickets or Boards Do I Need?

The formula and gap rules for counting fence pickets, boards or palings.

How Much Stain or Paint Do I Need for a Fence?

Estimate the stain or paint for a fence from area, coverage and coats.

How Much Does a Fence Cost to Build?

Estimate fence cost from the material list - posts, panels, concrete and labour.

Fence Types Compared

Wood, vinyl, chain link, privacy and picket fences compared, with calculator settings.

Pipe Size & Friction Loss

Open calculator →

Sprinkler Pipe Size Chart

A PVC pipe size chart by GPM, the velocity rule and friction loss explained.

PVC Pipe Sizes for Irrigation

The PVC pipe sizes used in irrigation, and how PVC compares with poly on cost, freezing and fittings.

Stairs

Open calculator →

Stair Rise and Run Explained

Riser height, tread depth, the comfort rule and the code limits.

How to Cut Stair Stringers

Mark and cut stringers with a framing square, including the bottom-step deduction.

How to Build Deck Stairs

Measure, calculate and build exterior deck stairs, including the base footing.

How to Space Stair Balusters

The 4-inch gap rule, the even-spacing formula and how many balusters you need.

Roof Pitch & Rafter Length

Open calculator →

Roof Pitch Chart

Every x:12 pitch converted to degrees, percent and slope factor.

How to Measure Roof Pitch

Measure roof pitch with a level, a speed square, or from the attic.

Roof Shingle

Open calculator →

How Many Bundles of Shingles Do I Need?

Turn roof square feet into roofing squares and bundles of shingles to buy.

How to Measure a Roof for Shingles

Measure the footprint, add the pitch, and convert square feet to roofing squares.

Cladding & Weatherboard

Open calculator →

How Much Siding Do I Need?

Turn wall square footage into squares and boxes of vinyl or lap boards.

Vinyl vs Fiber Cement Siding

Upfront cost, maintenance, lifespan, fire and looks compared.

How to Measure for Siding

Break the walls into shapes, subtract openings, total into squares.

Pool Volume

Open calculator →

How Many Gallons Is My Pool?

The formula plus a chart of common pool sizes in gallons.

How Many Gallons in a Round Pool?

Round pool gallons by diameter and depth, with a full above-ground chart.

How Long Does It Take to Fill a Pool?

Pool fill time by volume and hose flow rate, with a chart.

How to Lower pH in a Pool

Bring pool pH down with acid, and fix the alkalinity that keeps pushing it back up.

Pool Chemicals: What You Actually Need

The six pool chemicals that do real work, what each is for, and what to skip.

Pool Maintenance: Weekly, Monthly and Seasonal

The weekly, monthly and seasonal pool routine, and how DIY compares with a pool service.

Landscaping & soil

Landscaping volume calculators - mulch, gravel, sod, topsoil and garden beds.

Mulch

Open calculator →

How Much Mulch Do I Need?

The depth guide and formula for buying the right amount of mulch.

Gravel

Open calculator →

Gravel Driveway: Depth, Base and How Much Gravel

Driveway layers, depths and how much gravel to order (with weight in tonnes).

Turf & Grass Seed

Open calculator →

How Much Sod Do I Need?

The formula, pallet coverage and waste margin for buying the right amount of sod.

How Much Does Sod Cost?

Estimate sod cost from the quantity - sod, delivery, ground prep and installation.

Sod vs Seed: Which Should You Choose?

Cost, speed, effort and grass choice compared, so you can pick sod or seed.

How Much Grass Seed Do I Need?

Sowing rates for a new lawn and overseeding, with the formula and a worked example.

St. Augustine Grass

Why St. Augustine is sodded not seeded, the main varieties, and how to care for it.

Zoysia Grass

Zoysia varieties, which come from seed vs sod, and how to establish and care for it.

Sir Walter Buffalo Grass

What Sir Walter buffalo turf is, why it is not sold as seed, and how to plan a lawn.

Raised Bed Soil

Open calculator →

How to Fill a Raised Garden Bed

Soil mix ratios, fill depth and a cheap way to fill tall raised beds.

Irrigation & Sprinkler Zone

Open calculator →

How Many Sprinkler Heads Per Zone?

The flow formula, a heads-per-zone table and a worked example for sizing sprinkler zones.

How Much Does a Sprinkler System Cost?

Cost per zone, DIY vs installed, and the parts that drive an irrigation budget.

How to Winterize Sprinklers

Shut off, drain and blow out a sprinkler system before the first hard freeze.

Sprinkler Valves

How sprinkler valves work, the two types, the fault-finding order and how to replace one.

Drip Irrigation vs Sprinklers

How drip, sprinklers and soaker hose compare on water use, cost and what each suits.

How Long Should I Run My Sprinklers?

The precipitation-rate run-time formula, typical times, and cycle-and-soak.

How to Test Your Water Pressure and Flow

How to test static water pressure and GPM flow, how they differ, and how to use them.

Sprinkler Head Types

The sprinkler head types compared - throw, flow and precipitation rate, and why they never share a zone.

Retaining Wall

Open calculator →

How Many Retaining Wall Blocks Do I Need?

Turn a wall length, height and block size into a block count, by the course.

How Much Gravel Do I Need for a Retaining Wall?

Size the base leveling pad and the drainage backfill gravel for a retaining wall.

How Much Does It Cost to Build a Retaining Wall?

Estimate retaining wall cost from the material list plus labor.