Free Sandcastle Base Radius & Stability Calculator

Calculate the physics of your sand structure for maximum stability and volume efficiency.

Calculation Inputs

50 cm
30°

Results & Preview

Base Radius

86.6 cm

Vol. Needed

392.7 L

Pro Tip: Achieving Higher Angles

Sand stability is determined by the "angle of repose." While dry sand naturally settles at ~30°, you can drastically improve your structure's verticality by introducing a 1:8 ratio of water to sand and compacting the layers firmly (the "pancake" method). This allows angles up to 70-80°!