Use PER Calculator when you need to compute the protein efficiency ratio as weight gain in grams divided by protein consumed in grams; the ratio is signed and cannot fall below minus one. Enter Protein consumed and Weight gain using the definitions and units below so the result can be reproduced.

Protein consumed

Protein consumed in grams; must be greater than zero.

Weight gain

Weight gain in grams; signed, and no lower than negative the protein consumed.

The published tool contract uses this rule: Compute the protein efficiency ratio as weight gain in grams divided by protein consumed in grams; the ratio is signed and cannot fall below minus one.^[1]

Protein efficiency ratio

Protein efficiency ratio; signed grams of gain per gram of protein.

A ratio or percentage can conceal the scale of its numerator and denominator and becomes sensitive to measurement error when the denominator is small.

Retain the original Protein consumed and Weight gain values and their units alongside the result. Dairy BCS Ratio Mapping is useful when you instead need to map a precomputed body-condition ratio onto a one-to-five score with round(ratio times five), clamped to the scale. This is a heuristic mapping, not a substitute for visual and palpation scoring. Brain-Body Ratio provides another view by helping you compute the gross brain-body mass ratio as brain mass in grams divided by body mass in kilograms.

• Dairy BCS Ratio Mapping

  Map a precomputed body-condition ratio onto a one-to-five score with round(ratio times five), clamped to the scale. This is a heuristic mapping, not a substitute for visual and palpation scoring.

• Brain-Body Ratio

  Compute the gross brain-body mass ratio as brain mass in grams divided by body mass in kilograms.

• 260/280 Ratio

  Calculate the A260/A280 purity ratio used to assess nucleic acid contamination by protein.