Render Calculator
Work out how much render you need. Enter the wall area, the calculator returns the number of 20kg bags (with waste) and an indicative cost, based on a typical single-coat thickness.
How we estimate this
A 20kg bag of pre-mixed render covers roughly 1.2 to 1.4 square metres at a standard 10mm coat, so a 30m² wall needs around 23 to 26 bags plus waste. A second coat or a thicker build roughly doubles that.
Pricing reviewed: November 2026.
Pricing reviewed November 2026. Indicative Australian costs, not a quote.
Understanding renders in Australia
A 20kg bag of pre-mixed render covers roughly 1.2 to 1.4 square metres at a standard 10mm coat, so a 30m² wall needs around 23 to 26 bags plus waste. A second coat or a thicker build roughly doubles that.
Coverage varies with the substrate and finish, a rough blockwork wall soaks up more than a smooth one. Buy a little extra from the same batch so colour and mix are consistent across the wall.
Frequently asked questions
How many bags of render do I need?
Roughly one 20kg bag per 1.2 to 1.4 square metres at a 10mm coat, so about 23 to 26 bags for a 30m² wall plus waste. A second coat roughly doubles it.
Does the surface affect how much render I need?
Yes, a rough or porous wall uses more render than a smooth one, and a thicker or two-coat finish uses more again. Allow extra and buy from one batch for a consistent colour.
Are you a supplier / rendering business?
Everyone on this page is working out what render costs because they are ready to hire. Put your business right beneath the calculator, in your state, so you are who they find. From $50/mo.