Five calculators for around the house — splitting household bills fairly, what an appliance costs to run, how much paint or flooring a room needs, and sizing a radiator or converting watts, amps and volts for an electrical job. All calculations run locally in your browser, with no sign-up.
Which one do I need?
Common questions
How does the household bill splitter handle unequal contributions?
You set each person's contribution percentage once, then add as many bills as you like — rent, utilities, broadband — and it applies that split to the total automatically instead of you doing it per bill.
What do I need to know to size a radiator with the BTU calculator?
Just the room's dimensions and, optionally, factors like glazing and insulation quality — it estimates the heat output (in BTU and watts) needed to keep the room warm, which is what you'd match against a radiator's rated output.
Does the paint coverage calculator account for doors and windows?
Yes — enter the room dimensions plus the area taken up by doors and windows and it subtracts them before working out how much paint or flooring you need, so you're not buying for wall space that isn't there.