Calculating pig weight
Weighing pigs accurately is essential for effective farm management — whether you’re monitoring growth rates, planning when to market animals, calculating feed costs, or estimating carcass yields. But not every farm has access to a livestock scale. That’s where tools like the Pig Weight Calculator come in: they help you estimate a pig’s live weight quickly and reliably using simple measurements.
At its core, the approach uses two physical measurements of the animal: heart girth and body length. Heart girth is the circumference of the pig’s chest just behind its front legs, and body length is measured from the base of the ears to the base of the tail. When you measure these two dimensions and enter them into the online calculator, the tool uses a well-established formula to estimate the pig’s weight — eliminating guesswork and the need for heavy scales.
How the Calculation Works
The formula behind most pig weight calculators — including the Farm Manager tool — is based on a standard livestock weight estimation method:
Measure heart girth (in centimetres or inches) — wrap a soft measuring tape around the pig’s chest.
Measure body length — from base of ears to base of tail.
The calculator (or your own math) then uses these values in this core equation:
Weight ≈ (Heart Girth × Heart Girth × Body Length) ÷ 400
This gives an estimate of the pig’s live weight (in pounds if measurements are in inches). If you measure in metric (centimetres or metres), many online tools automatically convert your inputs and output the estimate in kilograms.
This method has been widely used by farmers and extension services because it correlates strongly with actual pig weights and provides a practical alternative when scales aren’t available. Adding data into the Pig Weight Calculator does all of the arithmetic for you — simply input your measurements and get a weight estimate instantly.
Why It’s Useful
No scale needed: Great for small farms or field conditions.
Fast and repeatable: Helps you track growth over time without stressful handling.
Decision support: Accurate weight estimates support feeding plans, medication dosing, and market timing — improving overall farm efficiency.