Loan Standard Deviation Calculator
Paste any list of numbers — or upload a CSV file and let the browser do the parsing, free (paid sites charge for file uploads) — and get the full statistics summary, not just the standard deviation.
Frequency summary
| Value | Count | Share |
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How it works
The mean is the sum divided by the count. The standard deviation measures spread around that mean: square each value's distance from the mean, average the squares (that is the variance), then take the square root. Two flavors: divide by N for the population SD — when your data IS the whole group — or by N−1 for the sample SD (Bessel's correction) when your data is a sample of something bigger; sample SD is always a bit larger. The median is the middle value, and the mode is the most frequent.
Frequently asked questions
Should I use population or sample standard deviation?
Use population SD when the data you have is everything you care about (all 30 students in THIS class). Use sample SD when your numbers are a sample meant to describe a bigger group (30 voters polled to estimate a city). Most published research reports the sample version.
How do I calculate standard deviation by hand?
Find the mean, subtract it from every value, square each difference, average the squares, and take the square root. For 2, 4, 4, 4, 5, 5, 7, 9 the mean is 5, the squared distances sum to 32, variance is 32 ÷ 8 = 4, and SD = √4 = 2.
What does a CSV upload accept?
Any plain text or CSV file — every number found in the file becomes a data point, in file order. A header row is fine: words are simply ignored. The file is parsed by your browser on your device; it is never sent anywhere.
What if every number is different — is there still a mode?
No: when no value repeats, there is no mode, and the calculator says so. When two values tie for most frequent, both are listed (the dataset is bimodal).
🎓 Working with class data?
The Final Grade Calculator shows the exam score you need — or your course grade for any what-if score.