I've just updated the hip Roof and Pitch/Angle calculators at Pitch to Angle - Angle to Pitch Converter so when you visit with an iPad or Android tablet, you can lay the device on an incline and directly measure the angle. Nothing to download or install, just go to the page.

With the roof calculators, tap the green 'Start Measuring' button to display the pitch and angle. Then tap the button again to capture the current angle, pre-fill the roof angle input and calculate the roof.

The Start button will appear only if your device is capable of measuring angles.

: