Direct and inverse proportion calculator

You can use this calculator when you want to find a value using the unitary method. You can choose direct or inverse proportion. An example of direct proportion is “if 10 T-shirts cost £200, how much do 20 T-shirts cost?” An example of inverse proportion is “if I download a film at 10 Mbit/s in 200 seconds, how many seconds would it take at 20 Mbit/s?” You can read more about the theory in the separate article on proportion.