Home and health
Home & DIY
23 free tools for DIY jobs and energy bills: how much paint, how many tiles or rolls of wallpaper you need, bags of concrete, staircase steps, cable size and voltage drop, what heating or air conditioning really costs, sizing a solar PV system, comparing two energy offers, and a knitting gauge calculator.
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Insulation savings
Wall U-value layer by layer, the kWh and money insulation saves, and the payback in years.
Knitting gauge: stitches, rows and yarn
Turn your swatch into stitches to cast on, rows to work and balls to buy.
Cutting plan
How many bars you need for your cut list, with patterns, offcuts and waste.
Hot water cost
What a shower costs, how much energy the tank drinks and which size you need.
Size your solar PV system
How many kWp and panels your consumption needs, what it produces, how much you use on site and when it pays back.
How many radiator sections
From the heat a room needs to the number of sections, using the real output at your flow temperature.
All tools, A to Z 23
AC BTU calculator
The right BTU and kW for the room's air conditioner.
Air conditioner cost
What an hour, a night and a whole season of air conditioning cost, from BTU and class.
Cable size and voltage drop
Voltage drop and the smallest cable for a run, with ampacity and maximum length.
Compare two energy offers
Put two electricity or gas contracts side by side on comparable items and see the real yearly gap.
Cutting plan
How many bars you need for your cut list, with patterns, offcuts and waste.
Dew point
Condensation and mould: when they form at home
Firewood volumes, weight and kWh
Stacked, loose and solid cubic metres turned into kilos and kWh, plus how much a season takes.
Heating cost comparison
Pellets, gas, firewood, oil, LPG, electricity or a heat pump: what one kWh of heat really costs and the bill for a season.
Hot water cost
What a shower costs, how much energy the tank drinks and which size you need.
How many bags of concrete
From the size of the pour to the bags to buy, plus the site mix proportions.
How many radiator sections
From the heat a room needs to the number of sections, using the real output at your flow temperature.
Insulation savings
Wall U-value layer by layer, the kWh and money insulation saves, and the payback in years.
Knitting gauge: stitches, rows and yarn
Turn your swatch into stitches to cast on, rows to work and balls to buy.
Ohm's law calculator
V, I, R and P: enter two, get the rest
Paint calculator
How many liters of paint you need for a room.
Resistor color code
Read a resistor's value from its colors
Room area & volume
Area, volume, wall surface and perimeter of a room.
Room lumens
How many lumens you need to light a room well.
Size your solar PV system
How many kWp and panels your consumption needs, what it produces, how much you use on site and when it pays back.
Slope calculator
Slope in percent and degrees from rise and run.
Staircase steps
Ideal number of steps, riser and tread of a staircase.
Tile calculator
How many tiles you need for a floor or wall, waste included.
Wallpaper calculator
How many wallpaper rolls you need for a room.