Estimate your pig’s live weight without a scale using the standard swine tape-weight formula. Enter heart girth and body length to get live weight, hanging weight, freezer yield, and approximate market value.
The standard formula used by farmers, extension agents, and livestock buyers to estimate pig weight without a scale is:
Weight (lbs) = Heart Girth² × Body Length ÷ 400
Heart girth is measured in inches with a soft tape around the pig’s body directly behind the front legs — think of it like measuring a barrel’s circumference at its widest point behind the shoulders. Body length is measured in inches along the spine from between the ears to the base of the tail. Both measurements must be taken while the pig stands squarely on all four legs for accurate results.
The divisor of 400 was empirically derived from measurements of thousands of pigs across different breeds and weight classes. It works best between 40 and 300 pounds — the range covering feeder pigs through slaughter weight. Below 40 pounds the formula tends to slightly underestimate, and above 300 pounds it tends to overestimate because mature sows and boars carry weight differently than growing market pigs. The breed adjustment factor in this calculator corrects for known differences in body density and frame type across common breeds.
For most market-weight pigs between 200 and 260 pounds, the tape-weight formula is accurate to within ±5% of a scale reading — close enough to decide when to schedule a butcher date or estimate how much feed remains. That said, body condition matters: a well-muscled pig at 220 pounds will actually weigh more than a soft, fat pig with the same girth and length, because muscle is denser than fat.
Live weight is the pig’s weight on the hoof, before slaughter. This is what the tape formula estimates.
Hanging weight (also called on-the-rail or carcass weight) is what remains after the pig is slaughtered, bled, gutted, and the head is removed. For market pigs, hanging weight is typically 72–75% of live weight. Heavily muscled breeds like Duroc and Berkshire trend toward the high end; fatter or lighter breeds trend lower.
Freezer weight (cut-and-wrap weight, or take-home weight) is what you actually put in your freezer after the butcher removes bones, excess fat trim, and processing waste. This is typically 70–75% of hanging weight, or roughly 54–56% of live weight. A 250-pound live pig typically yields about 180 pounds hanging and 125–135 pounds in the freezer.
Market value is calculated at hanging weight because that is how most custom butchers and buyers price pork. Prices vary widely by region, season, and whether you are selling live, by hanging weight, or as cut-and-wrapped retail cuts. The estimate shown is for planning purposes; get a local quote before making business decisions.
Not all pigs carry weight the same way for a given girth and length. The breed adjustment factors in this calculator reflect real differences in muscle density, frame structure, and body composition.
Duroc pigs are the most heavily muscled common breed — they are built wide and deep, so a Duroc with a 47-inch girth genuinely weighs more than a Landrace with the same girth because the Duroc is denser through the hams and loin. Berkshire pigs are similarly muscular but slightly shorter in the back. Yorkshire and Hampshire are close to the standard formula baseline. Landrace is long and lean — the standard formula may slightly overestimate because their long frames carry less depth per inch than blockier breeds. Spotted and Poland China crosses tend to be finer-boned with a lighter frame.
If you are working with a heritage breed not listed — Tamworth, Ossabaw, Kunekune, or Mulefoot — use Generic/Mixed. Heritage breeds are typically leaner and have smaller frames than commercial breeds; the formula will give a useful ballpark but expect more variability.
For market-weight pigs (150–280 lbs) in normal body condition and standing squarely when measured, the standard formula is accurate to within ±5% of a scale reading in most cases. A 250-pound pig on the scale typically measures between 237 and 263 pounds with the tape method. Accuracy drops outside this range — the formula tends to underestimate young pigs below 50 pounds and overestimate very large sows over 400 pounds. Sows in late gestation also skew the measurement because pregnancy shifts weight distribution. For deciding when to schedule a butcher date, comparing pigs in a litter, or estimating feed-to-finish costs, the tape method is more than accurate enough.
The traditional market weight target for a finishing pig is 240–280 pounds live weight, reached at around 5–6 months of age on a standard feeding program. At this weight the pig has adequate back fat (1.0–1.2 inches) for good eating quality without being excessively fat, and the loin muscles are at peak development. Going heavier than 280 pounds does not improve eating quality — extra weight above market target goes primarily to fat, not muscle, so your pounds-of-meat-per-pound-of-feed ratio deteriorates. Heritage breeds like Berkshire and Duroc crosses often taste best harvested at slightly higher weights (260–300 lbs) because fat marbling improves with age, but standard commercial breeds are best at 240–260 lbs. Anything significantly over 300 pounds is inefficient unless you are specifically raising for lard production or as breeding stock.
Whole roaster pig: 50–120 pounds live weight, 6–14 weeks old. The pig is tender throughout and fits on a standard roaster.
Freezer pork for a family: 220–260 pounds live weight. At 250 lbs you get roughly 135–145 pounds of packaged pork in the freezer — enough for a family of four for a full year if pork is a regular part of your diet.
Selling to other families: 220–280 lbs gives the most consistent hanging weight (160–200 lbs) that custom butchers work with efficiently.
Cured products (ham, bacon, prosciutto): Heavier pigs at 280–350 lbs produce larger hams and thicker bellies that cure more evenly. Traditional European cured pork — Iberian ham, Parma prosciutto — typically comes from pigs at 350+ lbs specifically selected for fat depth.
A reliable rule of thumb is 1 cubic foot of freezer space per 35–40 pounds of packaged pork. A 250-pound live pig that yields roughly 135 pounds of packaged meat needs approximately 3.5–4 cubic feet. That fits comfortably in a 5-cubic-foot chest freezer with room to spare. A 7-cubic-foot chest freezer (a very common size) can hold a whole pig with room for other food. Note that vacuum-sealed or tightly wrapped cuts pack more efficiently than loosely wrapped cuts, and bone-in cuts take significantly more space than boneless. If your butcher leaves hams and ribs bone-in, assume the higher end of the space estimate. See our food storage calculator for longer-term planning.
Move the pig to a flat surface and encourage it to stand squarely with weight distributed evenly on all four feet — a pig leaning or stretching forward changes the measurement. Bring the tape around the body just behind the front legs, right at the narrowest point behind the elbows. Pull the tape snug but not tight enough to compress the body; you want tension similar to how you would measure your own waist. Take 2–3 readings and average them. The most common mistake is measuring too far back toward the middle of the body, which inflates the number and causes an overestimate. A soft fabric tape or livestock measuring tape works best; a stiff metal tape is harder to keep snug around a rounded surface and uncomfortable for the pig.