New calculators
The latest additions to the catalog.
Electricity cost calculator
kWh and dollars per day / month / year for any appliance
Sales tax / VAT calculator
Add tax to a net amount or extract the tax already inside a gross amount (US sales tax or EU VAT)
Running pace calculator
Pace per km and per mile from total time + distance, with 5K/10K/half/marathon presets
Standard deviation calculator
Sample (n−1) and population (n) standard deviation + variance from a list
Break-even calculator
Units (and revenue) needed to cover fixed costs given price and variable cost
Profit margin calculator
Margin %, markup %, and dollar profit from cost and revenue
Density calculator (ρ = m/V)
Solve for density, mass, or volume given the other two
Ohm's law calculator
Solve for V, I, R, or P given any two — with power dissipation
Concrete calculator
Volume, weight, and 50 kg bag count for a concrete slab (with waste factor)
Paint calculator
How many liters of paint a room needs — wall area minus doors/windows × coats