Geotextile calculator
Tell us the area and what the geotextile is for. The calculator picks the Retech grade and works out the rolls, laps included, and the consignment weight.
Free access for engineers and buyers
Sign in with a one-time code: no password to remember. All ten Retech calculators then open on this device, and your details reach the Retech desk so an engineer can help with your project. We do not share them.
Results appear here as you type.
How the calculation works
Non-woven: pick what the geotextile is for and the calculator uses Retech's grade for that job: 150 GSM for landscaping and drain filters, 200 GSM for separation on firm ground, 300 GSM on soft ground or with gabions, 400 GSM under riprap or protecting a pond or canal liner, 600 GSM protecting a landfill or deep-reservoir liner. Each 5 m wide roll covers its width less the side lap times its length less the end lap, so the order area is the net area × (5 ÷ (5 − lap)) × (length ÷ (length − lap)) plus 3% cutting waste, with 300 mm laps (500 mm on soft ground). Rolls = order area ÷ roll area, rounded up. Example: a 100 × 50 m yard on firm ground needs RNW 200 GSM: about 5,500 m² with laps, 11 rolls of 5 × 100 m, about 1,100 kg.
Planning quantities for budgeting and enquiry. A Retech engineer confirms the grade and quantity against your drawings before order.