Flagstone Patio Calculator

About this calculator

Flagstone — flat, irregular slabs of sedimentary rock like sandstone, limestone or quartzite — is sold by weight rather than by piece because its thickness and shape vary, so ordering the right amount means converting a patio's square footage into tons rather than counting stones. A common industry rule of thumb is that one ton covers roughly 120 square feet at 1.5 inches thick, with coverage scaling down as the chosen thickness increases (a thicker stone naturally covers less area per ton).

This calculator takes your patio's area and the stone thickness you plan to use and estimates the tons of flagstone to order, the same conversion landscapers and stone suppliers use when quoting a patio, walkway or dry-stack wall job, helping avoid both a costly excess delivery and a mid-project shortfall.