Curved retaining wall calculator

Measure the arc, not the chord

A curve’s length is its radius multiplied by its central angle in radians. An angle in degrees is converted by multiplying by π/180. A semicircle has an angle of 180°, and a quarter circle has an angle of 90°.

Use the radius of the same reference line where your unit coverage is measured. A radius measured at the front face and a width measured at a different line can make the block count inconsistent.

Arc length = radius × angle in degrees × π/180

Example: 15-foot radius, 90-degree bend

The arc length is 15 × 90 × π/180 = 23.56 feet. The straight chord is shorter, so using it would understate the wall run. The estimator takes 23.56 feet into the same full-course count used by the main calculator.

With 16-inch modules, that run rounds to 18 units per course. At six exposed 6-inch courses plus one buried course, the net count is 126. The starting curved-wall waste allowance of 15% produces 145 units to order.

Where the geometric estimate stops

This tool does not determine whether a product can form the chosen radius, the gap between tapered blocks, or the different radii of setback courses. Manufacturer curve limits and a course-by-course layout may change the material schedule.

Allow separately for corner units, end units, cap cuts and extra reinforcement at curved details. The tool uses one constant reference arc for every course; a tall wall with significant batter may need separate course lengths.