Standard Deviation Calculator — paste a dataset and get sample or population standard deviation in seconds, with every step shown. This standard deviation calculator finds sample SD (s, n − 1) and population SD (σ, N). Switch formulas on the same list. See mean, variance, deviations, and the square root — not only the headline number. HOW TO USE • Paste or type numbers separated by commas, spaces, or new lines • Choose Sample or Population • Tap Calculate • Open Show solution for the working table WHAT YOU GET • Sample standard deviation and population standard deviation • Mean, variance, count, range, sum, min, max • Median, Q1, Q3, IQR, coefficient of variation, standard error • Step-by-step standard deviation: mean → deviations → squares → divide → square root • Bell curve with the 68–95–99.7 rule, dataset bars, and a box plot • Tap a value to see its z-score vs the mean • History of recent calculations on this device Built for homework, exam scores, lab readings, and class spread. Datasets stay on your phone — no account and no cloud sync of your numbers. The calculator works offline. Ads, analytics, and purchases use the network when those features run. LIFETIME PRO (optional, one-time — not a subscription) Remove ads, keep 8 decimal places without a video, and export the working as PDF. Standard Deviation Calculator by TQ Tech. Spread, instantly.