Standard Deviation Calculator
Mean, variance, and standard deviation of a list of numbers.
Result
Fill in the inputs to see your result.
Inputs
Related calculators
Calcxo gives you the answer plus the reasoning behind it.
How this calculator works
Methodology, assumptions & limitations
Standard Deviation Calculator runs entirely in your browser. It applies the standard formula for this calculation to the values you enter and updates the result as you type — nothing is sent to a server, and no inputs are stored.
Assumptions
- Inputs are entered in the units shown next to each field.
- Values are treated as exact; the calculator does not round inputs before computing.
- Results assume the standard, widely-used formula for this type of calculation.
Limitations
- Real-world fees, taxes, regional rules, or special cases are not modelled unless explicitly listed.
- The result is for general information and planning — it is not professional advice.
- When precision matters (legal, medical, financial decisions), confirm with a qualified professional or an authoritative source.
Calcxo provides general-purpose calculators for information and planning. Results are not professional financial, medical, legal, or tax advice. See our disclaimer and sources & methodology for more.
Quick answer
Standard Deviation Calculator: in one paragraph
Mean, variance, and standard deviation of a list of numbers.
What this calculator does
Standard Deviation Calculator takes the values you enter and returns the result instantly in your browser. Mean, variance, and standard deviation of a list of numbers.
Why people use it
- Get an answer in seconds without spreadsheets or manual math.
- Try several scenarios side by side by tweaking the inputs.
- Share or revisit the page later — nothing you type is stored.
- Pair it with the related tools below to cross-check your numbers.
How to use the Standard Deviation Calculator
A concrete walkthrough you can follow line by line.
Open the Standard Deviation Calculator above, fill in each field with a real value, and the result updates as you type.
1. Fill in the required fields
Every field labelled without 'optional' needs a value. Hints under each label explain the expected unit.
2. Read the headline result
The big number at the top is the primary answer. The caption underneath translates it into plain English.
3. Check the breakdown
Smaller rows show the inputs and intermediate steps the calculator used, so you can verify the math.
4. Try a different scenario
Adjust any field and the result recalculates instantly — no need to reload.
Result
You'll have an answer plus the breakdown of how it was computed, ready to compare or share.
When to use this calculator
- You need a quick, reliable standard deviation calculator answer.
- You want to compare a few what-if scenarios before making a decision.
- You're sanity-checking a number you got from somewhere else.
- Use a more specialised calculator from the related list when your case has extra inputs (taxes, fees, schedules) this one doesn't model.
Common mistakes
- Treating the result as exact when one of the inputs is a rough estimate.
- Mixing units between fields without converting first.
- Forgetting that real-world fees, taxes, or rounding can shift the answer slightly.