Show the working, state the assumptions.

What this is

Field Measure is a small set of free planning calculators for horse property. The first one answers a question that comes up on every arena build and every refresh: how much footing material do I actually need, and what will the supplier put on the truck?

Why it exists

Arena footing is bought in tons but specified in inches. Getting from one to the other means holding area, depth, volume, density, and a waste allowance in your head at the same time, usually while standing in a field. Get it wrong in one direction and you pay to haul away a surplus. Get it wrong in the other and the job stops halfway.

Most of the calculators we could find either hid their assumptions, demanded an email address, or buried the answer under advertising. We wanted one that shows its working, states its assumptions plainly, and gives you something you can print and hand to a supplier.

How the numbers are worked out

The geometry is deliberately unclever. Area is length times width. Volume is area times depth in feet. Cubic yards are cubic feet divided by 27. A waste factor, if you set one, is applied on top.

The only judgement call is density — the conversion from volume to weight. We use 100 pounds per cubic foot for plain sand, the figure published by Penn State Extension, which works out to 1.35 tons per cubic yard. For footing blended with fiber, geotextile, or rubber we use 90 pounds per cubic foot, because those additives are lighter than sand. That blended figure is an approximation and the calculator says so on screen. The actual mix your supplier delivers is the number that matters.

Where the guidance comes from

Depth recommendations and warnings come from published extension research rather than from us: Penn State Extension on arena footing selection and management, Rutgers NJAES on horse facilities, and the USDA Natural Resources Conservation Service design guide for earth and aggregate surfacing. Every one of those is linked from the calculator so you can read the source rather than take our word for it.

What it costs

Nothing, and there is no account to create. The calculators run in your browser and the numbers you enter never leave your device. The site is supported by advertising.

What is coming

Arena footing is the first tool, not the last. The intention is a small, well-made set covering the other quantities horse property owners have to estimate before ordering.

Get in touch

If a number looks wrong, or a calculation you need is missing, we would rather hear about it. Write to hello@paddockcalc.com.