Polymeric sand calculator

Bags of polymeric joint sand for pavers, from the paver size and joint width.

Pallets of grey concrete paving blocks stacked at a yard

How it works

Each paver and its share of the joint make a rectangle (length + joint) × (width + joint). The joint is the part of that rectangle the paver doesn't cover. We multiply that share by the paved area and the joint depth for the volume of sand, then convert to weight using 1,800 kg/m³ (106 lb/ft³), the density on Sika's data sheet for its polymeric sand, and divide by the bag weight.

This fills every joint to the full depth of the paver, so it errs on the high side: bedding sand usually rises into the bottom of the joints. Sika gives 60–90 sq ft (5.6–8.4 m²) per 50 lb bag for narrow joints, and Alliance Gator says pavers with spacer bars use 10–15% less.

Worked examples

A 12 × 12 ft patio of 4 × 8 in pavers, 2⅜ in thick, with ⅛ in joints: the joints are 4.5% of the surface. With 10% extra that's 4 bags of 50 lb.

15 m² of 200 × 100 mm blocks, 60 mm thick, with 3 mm joints: 4 bags of 22.7 kg.

Tips

Fill joints when the pavers are completely dry, sweep and compact until the sand stops settling, and leave it just below the top edge as the product's instructions say. Blow every grain off the surface before you mist it with water, or it can leave a haze.

Common questions

How many bags of polymeric sand do I need?

It depends on the joint width and paver size more than the area. For tight joints between standard pavers, makers quote roughly 60–100 sq ft per 50 lb bag; wide joints and flagstone take far more. Enter your pavers to work it out.

Do I need more sand for wider joints?

Yes. Sand use rises almost in step with joint width: double the joint and you roughly double the sand.

Reviewed by Alex Rowan, Editor. Last reviewed 17 October 2026. How we calculate · Report a problem