The easiest method is to make a drawing of the pond, then use a tape measure to measure the pond. You can then use the following rule of thumb:

• Length = pond length + 2 x depth of pond + 2 x 70 cm
• Width = pond width + 2 x depth of pond + 2 x 70 cm

Incorporate the measurements thus obtained into the drawing. Then the garden center or pond specialist can calculate for you how much pond liner you will need. Click here for a handy step-by-step plan for building a pond.