How big is a Quail Egg?

A quail egg is the egg of the Japanese quail, a small bird farmed for its eggs and meat. It is about 3 centimeters (1.2 inches) long and 2.5 centimeters (1 inch) wide, and weighs about 10 grams (0.35 ounce). Its white shell is covered in dark spots.

Size

An egg's size is given as two measurements: its length along the long axis, and its width across the widest part. Scientists measure both with calipers, a tool that grips an object between two jaws. In a 2016 study in India of three varieties of Japanese quail, the eggs averaged 31.4–32.5 millimeters long and 24.3–25.8 millimeters wide.

A 2022 study at Ohio State University measured 100 eggs from ordinary Japanese quail. They averaged 30.8 millimeters long and 24.0 millimeters wide, and weighed 9.5 grams.

Size comparisons

• A quail egg is about as wide as a square inch: 24–26 millimeters across its widest part, against the square's 25.4 millimeters.
• Its length is about 1.6–1.7 times the width of a U.S. penny.
• US grading rules require a dozen large chicken eggs to weigh at least 24 ounces, an average of 57 grams (2 ounces) an egg. That is five to six times the weight of a quail egg.
• About eight quail eggs laid end to end would stretch across a basketball.

The bird that lays them

The Japanese quail (Coturnix coturnix japonica) is native to East Asia and is now kept around the world. It is the smallest bird species farmed for food. Females begin laying at about 6 weeks old and can lay 250–300 eggs a year.

Each egg is large for the size of the bird that lays it. A quail egg weighs about 8 percent of the female quail's body weight, while a chicken's egg weighs about 3 percent of the hen's.

Why the shells are spotted

A quail eggshell is white, with spots that range from brown to black and sometimes blue or green. The colors come from two pigments made in the female quail's oviduct, the passage the egg travels down as its shell forms. Both are laid down on the shell together.

The mix of pigments sets the color of the spots. Protoporphyrin is the main pigment in brown spots. Biliverdin, alone or combined with zinc, is the main pigment in the blue and green ones.

Sources

• Body weight, egg production, and egg quality traits of gray, brown, and white varieties of Japanese quail (Coturnix coturnix japonica) in coastal climatic condition of Odisha. Bagh et al., Veterinary World, 2016.
• Myostatin Mutation in Japanese Quail Increased Egg Size but Reduced Eggshell Thickness and Strength. Lee et al., Animals, 2022.
• Effect of the pigmentation, shine, weight, and shape index of the quail egg (Coturnix coturnix japonica) on the hatchability rate. Gutiérrez et al., Journal of Advanced Veterinary and Animal Research, 2021.
• United States Standards, Grades, and Weight Classes for Shell Eggs (AMS 56). US Department of Agriculture, Agricultural Marketing Service, 2000.
• NIST Guide to the SI, Appendix B.8: Factors for Units Listed Alphabetically. National Institute of Standards and Technology, 2025.
• Coin Specifications. United States Mint, 2026.
• Official Basketball Rules 2026: Basketball Equipment. FIBA, 2026.