Home and garden projects

Measure once and let Varlig work out the rest: wall and floor areas, tins of paint, packs of flooring, bags of gravel and what it all costs. Mix metres, centimetres and feet as you like, and change a measurement to see every total update.

Painting a room

Measure the walls, take off the door and window, and turn the area into tins using the coverage printed on the tin.

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# Spare bedroom, two coats

long wall = 4 m

short wall = 3.5 m

ceiling height = 2.4 m

walls = 2 * (long wall + short wall) * ceiling height gives 36 m²

door = 0.8 m by 2 m

window = 1.2 m by 1.5 m

paint area = walls - door - window gives 32.6 m²

paint needed = paint area * 2 / (12 m²/L)

paint needed to 1 dp gives 5.4 L

tins = ceil(paint needed / 2.5 L) gives 3

tins at £28 gives £84.00

Lengths multiply into areas, with * or with by the way sizes are written on a plan, and dividing an area by a coverage in m²/L leaves litres. ceil rounds up, because you can’t buy part of a tin, and tins at £28 prices them. See Arithmetic with units and Function forms.

Flooring an L-shaped room

Split an awkward room into rectangles, add them together, and allow 10% extra for offcuts.

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# Living room with a bay

main part = 5.2 m by 3.8 m gives 19.76 m²

bay = 2.4 m by 150 cm gives 3.6 m²

living room = main part + bay gives 23.36 m²

living room in sq ft to 0 dp gives 251 ft²

with waste = living room + 10%

packs = ceil(with waste / 2.2 m²) gives 12

packs at £36 gives £432.00

Metres and centimetres mix freely and the area still comes out in square metres. in sq ft helps when a shop or an old floor plan uses feet. Dividing by the area in one pack gives a plain number of packs. See Squares, cubes and powers.

Gravel and lawn seed

Work out how much gravel a path needs, whether loose bags or a bulk bag is cheaper, and how much seed a new lawn takes.

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# Garden path, 5 cm of gravel

path = 6 m * 0.9 m * 5 cm gives 0.27 m³

gravel = path * 1600 kg/m³ gives 432 kg

bags = ceil(gravel / 25 kg) gives 18

small bags = bags at £6.50 gives £117.00

# A bulk bag holds 850 kg for £95

small bags - £95 gives £22.00

# New lawn, seed at 35 g per m²

lawn = 8 m by 5 m gives 40 m²

lawn * 35 g/m² in kg gives 1.4 kg

A depth in centimetres times lengths in metres gives cubic metres, and a density in kg/m³ turns that volume into a weight. Here the bulk bag saves £22 and leaves gravel to spare. See Arithmetic with units.

DIY conversions and your own units

Older houses are measured in inches and feet, and DIY shops sell in millimetres. Convert as you go, and define units for the things you’re counting.

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# Old house, metric shop

3/4 inch in mm gives 19.05 mm

8 ft in m to 2 dp gives 2.44 m

6'6" in cm gives 198.12 cm

# Fence panels are 1.8 m wide

unit panel = 1.8 m

fence = 14.4 m

fence in panels gives 8 panels

# Splashback in 30 cm tiles

unit tile = 30 cm * 30 cm

splashback = 2.4 m * 0.6 m

splashback in tiles gives 16 tiles

unit panel = 1.8 m defines a unit of your own, and in panels counts how many fit. Feet and inches written with ' and " convert like any other length, and multiply into an area: 12'6" * 10'3" gives 128.125 ft². See Custom units and Heights and weights in feet, stones and pounds.

Make it your own

• Measured the room in feet? 14 ft by 12 ft gives 168 ft², and in m² converts it for a metric shop.
• Price flooring by the square metre instead of by the pack: living room * £18/m².
• Buying carpet cut from a 4 m roll? £22/m² * 4 m gives the price per metre, £88.00/m.
• Count wallpaper rolls with unit roll = 5.3 m² and walls in rolls rounded up.
• Fill a raised bed: 2.4 m * 1.2 m * 30 cm in L gives the compost you need in litres.
• See what a heater costs to run: 2 kW * 3 hours * 24.5p/kWh gives £1.47, with the tariff written in pence as it is on your bill.
• Replace an old radiator rated in BTUs: 5000 BTU/h in W to 0 dp gives 1,465 W.