Pumpkin Weight Calculator (OTT)

Competitive giant pumpkins are often weighed with the Over-The-Top (OTT) method: measure maximum circumference plus stem-to-blossom end length plus perpendicular side-to-side width, all in inches, then apply the Great Pumpkin Commonwealth regression formula to estimate weight in pounds.

OTT is a field estimate for growers and festival weigh-offs — not a substitute for certified scales. Shape, wall thickness, and hollow seed cavities introduce error, especially on irregular fruit.

Example: 100 in circumference, 80 in stem-to-blossom, and 75 in side-to-side sums to 255 OTT inches — the formula returns a positive weight in pounds suitable for comparing against last year's personal best.

Metric mode accepts centimeters and converts to inches internally before the same GPC-style formula runs — toggle units to remap all three fields at once. Keep the tape level at the widest equatorial circumference; stem-to-blossom and side-to-side should be the maximum extents, not diagonal shortcuts.

OTT error grows on lopsided or flattened fruit. Dense Atlantic Giant types track the regression better than soft, heavily ribbed, or partially hollow specimens. Photograph each measurement for contest paperwork when organizers require evidence before the scale.

Competition growers often take OTT weekly through September and October to track growth rate, not just a single pre-weigh estimate. A sudden stall in OTT inches can signal stress, while a steep late surge is common on well-fed vines — use the calculator as a trend tool as much as a one-shot weight guess.

Carving pumpkins and pie types are far lighter per OTT inch than competition giants — do not use this estimate to guess the weight of a porch jack-o'-lantern. Home bathroom scales under the fruit (with a board) are better for ordinary carving sizes under about 50 lb.

Limits: pure geometry estimate — no affiliation with any weigh-off organization. Certified events use official scales; this page is for home and farm planning only.