Rounding Calculator
Round decimal numbers to any number of places.
This rounding calculator rounds any decimal number to a chosen number of places, or to the nearest whole number, ten, hundred, or other place value. It follows standard round-half-up rounding rules used in most everyday and academic contexts.
Enter a number and choose how many decimal places (or which place value) to round to, and the calculator returns the rounded result.
Worked Calculation Examples
| Scenario | Result | Calculation Step |
|---|---|---|
| 4.567 to 2 decimal places | 4.57 | The third decimal digit (7) is 5 or greater, so the second decimal digit rounds up from 6 to 7: 4.57. |
| 128 to the nearest ten | 130 | The ones digit (8) is 5 or greater, so the tens digit rounds up from 2 to 3: 130. |
Standard Rounding Rules
To round to a given place, look at the digit immediately to its right: if that digit is 5 or greater, round up; if it is 4 or less, round down (round off). Rounding 4.567 to two decimal places looks at the third decimal (7), which rounds the result up to 4.57.
Rounding vs. Significant Figures
Rounding to a decimal place fixes the number of digits after the decimal point, while rounding to significant figures fixes the total number of meaningful digits regardless of where the decimal point falls - the two approaches can produce different results for the same number.
How to Use the Rounding Calculator
- Open the Rounding Calculator and enter the values requested in the input fields.
- Check the units, percentages, dates, or time periods before reading the answer.
- Review the instant result and adjust any value to compare another scenario.
- Use the formula, example, and FAQs below to understand how the rounding calculator works.
Frequently Asked Questions
How do I round a number to two decimal places?
Look at the third decimal digit: if it is 5 or greater, round the second decimal digit up; if it is 4 or less, leave it unchanged (round off) and drop the remaining digits.
What is the difference between rounding up and rounding down?
Rounding up always increases the value to the next increment regardless of the following digit, while standard rounding rounds up only when the next digit is 5 or greater and rounds down (round off) otherwise.
How do I round to the nearest whole number?
Look at the first decimal digit: if it is 5 or greater, round the whole number up; if it is 4 or less, keep the whole number as is.
How do I use this rounding calculator?
Enter the known values, review the units or settings, and the calculator updates the result instantly. The formula and example on this page show how the answer is produced.
What does the Rounding Calculator calculate?
Round decimal numbers to any number of places. It is designed for fast browser-based calculations without sign-up, downloads, or manual spreadsheet setup.
What formula does this rounding use?
The formula is: rounded = round(value * 10^d) / 10^d. The 'round half up' convention most calculators use has a lesser-known alternative, 'round half to even' (banker's rounding), which some financial and statistical systems prefer specifically because it avoids a slight systematic upward bias that accumulates when rounding many .5 values consistently in the same direction across a large dataset.
Related Calculators
Percentage Calculator
Calculate percentages, percent of a number, and percentage changes fast.
Average Calculator
Calculate the average (mean) of a list of numbers with the median, mode and range, or a weighted average, with step-by-step working.
Scientific Calculator
Advanced math calculator supporting trigonometry, logs, exponentials, and roots.
Percentage Increase Calculator
Calculate the percentage increase or decrease from an old value to a new value, the new value after an increase, or the original value, with steps.
Fraction Calculator
Add, subtract, multiply, and divide fractions.
Ratio Calculator
Simplify ratios, solve A : B = C : D for a missing value, scale ratios, divide a quantity in a ratio and compare ratios, with steps.
Last updated: September 27, 2026.