Use pH paper or a pH strip and compare the color to the chart
Use a pH meter and read the displayed value
Use a universal indicator solution and match the resulting color to a pH scale
Test the liquid with litmus paper for acidic or basic behavior
Calculate pH from hydrogen ion concentration using pH = -log[H+]
Calculate pH from hydroxide ion concentration using pOH = -log[OH-] and pH = 14 – pOH
Measure the sample at a consistent temperature for accurate results