‘How Long’ in Tagalog

Gaano?
How ______?

Gaano karami?
How much?
(the amount, not the price)

Gaano karami ang kailangan mo?
How much do you need?

Gaano kalaki?
How big?

Gaano kadalas?
How often?

Gaano kalayo?
How far away?

Gaano kahaba?
How long? (an object’s length)

Gaano katagal?
How long? (period of time)

Gaano katagal ka na dito?
How long have you been here?

To ask how to do something, use the word paano.

Paano ito bubuksan? 
How to open this?