When to use this calculator
Round a number to a chosen number of decimal places. JavaScript binary floating-point can affect exact halfway values; positive ties round upward.
Explore the algebra & number calculators for other questions in this topic. For a related calculation, use the Set Subset Count Calculator: Count all subsets of a finite set of distinct elements.
PUTTING IT INTO PRACTICE
Rounding: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Number | 123.456 |
| Decimal places (integer) | 2 |
| Result | 123.46 |
- Check the input labels and enter the example values above.
- Apply the relationship: Round to nearest multiple of 10^(−places).
- The result is 123.46 , rounded for display.
How to interpret your result
JavaScript binary floating-point can affect exact halfway values; positive ties round upward.
Identify whether the question asks for one term, a total or a count of possible selections. Sequences use a fixed difference or ratio. In counting problems, order and replacement determine the correct model.
Frequently asked questions
Do combinations and permutations count the same thing?
No. Combinations ignore the order of selection; permutations count different orders separately.
When is the rounding calculator useful?
Round a number to a chosen number of decimal places. JavaScript binary floating-point can affect exact halfway values; positive ties round upward.
How do I use the rounding calculator?
Enter number, decimal places (integer). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Round to nearest multiple of 10^(−places).
What should I check before using the result?
JavaScript binary floating-point can affect exact halfway values; positive ties round upward.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
Calculators Map editorial process · Updated · Methods and limitations