Pitch-to-Crate Sizing Calculator

Convert a target attenuation depth over a playing surface into a module count, a tank footprint and an excavation depth. Storage volumes are net manufactured figures (H500 = 237.5 L, H400 = 190 L), not box volumes.

Playing surface

Attenuation depth over the catchment (mm) Set by your drainage design, not by this tool. 10–30 mm is a common band on UK sports schemes.

Module

Module layers

Cover over modules (mm) Bedding is taken as 150 mm. Cover depth must be confirmed against the project structural calculation.

Silt & freeboard allowance (%) CIRIA C737 requires long-term capacity to allow for silt. Zero means you have not applied one yet.

Result

142.8 m³

Storage required

602

Modules needed

151 m²

Tank footprint

1.75 m

Excavation depth

Working: 7,140 m² × 0.020 m = 142.8 m³. Two H500 layers store 0.950 m³ per m². Excavation = 0.15 m bedding + 1.00 m modules + 0.60 m cover.

This is a purchasing check, not a drainage design. It excludes connection voids, flow-control geometry and the designer’s safety margin, and it will not satisfy an approving body on its own. Required storage volume comes from your design storm and your consented discharge rate, which this tool does not calculate.

Send these numbers to Storm Manage for a quote