Z-score Calculator

Standard score from a value, mean, and standard deviation.

Z-score Calculator helps you standard score from a value, mean, and standard deviation. Enter value x, mean, and standard deviation, review the breakdown, and use the guidance below to understand what the number means — and what it does not. What the Z-score calculator does Z-score Calculator is built for arithmetic, algebra, geometry, and number tools. Standard score from a value, mean, and standard deviation. You enter value x, mean, and standard deviation, then Simple Calculators computes the result instantly. Results use standard school and engineering formulas that run privately in your browser. How the math works Enter Value x, the group’s Mean and its Standard deviation, all in the same unit. The calculator subtracts the mean from your value and divides by the standard deviation: z = (x − mean) ÷ standard deviation. It then says whether x is above or below the mean and which band it falls in (within 1, 2 or 3 standard deviations). Those percentages assume the data follow a bell-shaped (normal) curve. The formula: z = (x − μ) ÷ σ. x is your value, μ the mean and σ the standard deviation. z counts how many standard deviations x is from the mean.