Number Rounding Calculator
Round any number to decimal places, significant figures, or the nearest integer.
Positive numbers, negative numbers, and decimals are supported.
Rounded result
3.75
Round based on the digit after the final decimal place kept
Original number
3.746
Rounding place
2 decimal places
Checked digit
6
Direction
Rounded up
Difference
0.004
Mode
decimal
Rounding Rules
Basic rounding
If the next digit is 5 or greater, round up.
Round down
If the next digit is 4 or less, round down.
Decimal places
Round based on the digit immediately after the final decimal place kept.
Place values
Round to ones, tens, hundreds, thousands, and so on.
Significant figures
Count from the first non-zero digit.
Ceiling
Rounds up toward positive infinity.
Floor
Rounds down toward negative infinity.
Truncation
Cuts off digits without rounding.
Variable Explanations
Original number
The number entered by the user.
Rounded result
The number after applying the selected rounding rule.
Rounding place
The place value or decimal place being kept.
Checked digit
The digit immediately to the right of the rounding place.
Decimal places
Digits after the decimal point.
Significant figures
Meaningful digits in a number.
Difference
Rounded result minus original number.
How Rounding Works
Simpler value
Rounding replaces a number with a nearby simpler value.
Last digit kept
The rounding place is the final digit you keep.
Decision digit
The checked digit decides whether the kept digit changes.
Many targets
Numbers can be rounded to decimals, whole numbers, place values, or significant figures.
Practical use
Rounding helps with estimates, measurements, reporting, and readability.
Precision
Trailing zeros can show intended decimal precision.
Worked Examples
3.746 to 2 decimal places
Rounding place: hundredths
Checked digit: 6
Rule: 5 or more rounds up
Answer: 3.75
7.24 to 1 decimal place
Rounding place: tenths
Checked digit: 4
Rule: 4 or less rounds down
Answer: 7.2
842 to nearest hundred
Rounding place: hundreds
Checked digit: 4
Rule: 4 or less rounds down
Answer: 800
15,678 to nearest thousand
Rounding place: thousands
Checked digit: 6
Rule: 5 or more rounds up
Answer: 16,000
0.004567 to 2 significant figures
Rounding place: 2 significant figures
Checked digit: 6
Rule: 5 or more rounds up
Answer: 0.0046
99.95 to 1 decimal place
Rounding place: tenths
Checked digit: 5
Rule: 5 or more rounds up
Answer: 100.0
-3.46 to nearest whole
Rounding place: ones
Checked digit: 4
Rule: nearest-value rounding
Answer: -3
Round vs floor vs ceiling
Rounding place: whole number
Checked digit: varies
Rule: methods differ by direction
Answer: 3.7 → 4, floor 3, ceiling 4
Rounding Decimals, Whole Numbers, and Significant Figures
Decimal places
Controls digits after the decimal. Example: 12.345 to 2 decimals = 12.35.
Whole-number place values
Controls tens, hundreds, thousands, and more. Example: 12,345 to nearest hundred = 12,300.
Significant figures
Controls meaningful digits. Example: 0.012345 to 3 significant figures = 0.0123.
Common Rounding Mistakes
Understanding Your Results
Rounded result
The simplified number after applying the selected rule.
Checked digit
The digit that decided whether to round up or down.
Direction
Whether the rounded value increased, decreased, or stayed equivalent.
Difference
How far the rounded value is from the original.
Significant figures
The number of meaningful digits retained.
Frequently Asked Questions
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