Rounding Numbers Calculator
Calculator Use
Rounding calculator to round numbers up or down to any decimal place. Choose ones to round a number to the nearest dollar. Choose hundredths to round an amount to the nearest cent.
Rounding Numbers
Say you wanted to round the number 838.274. The final value depends on which place value you want to round to. Rounding 838.274:
- Rounding to the nearest hundred is 800
- Rounding to the nearest ten is 840
- Rounding to the nearest one is 838
- Rounding to the nearest tenth is 838.3
- Rounding to the nearest hundredth is 838.27
Basic Rules of Rounding
When you "round to the nearest _____" regardless of what goes in the blank the steps are nearly always the same:
- Identify which place value you are rounding to. The smaller the place value, the more accurate the final result.
- Look to the next smallest place value, the digit to the right of the place value you're rounding to. For example, if you want to round to the nearest ten look at the ones place.
- If the digit in the next smallest place value is less than five (0, 1, 2, 3, or 4), leave the digit you want to round to as-is. Any digits after that number become zeros, or drop-off if they're located after the decimal point. This is called rounding down.
- If the next smallest place value is greater than or equal to five (5, 6, 7, 8, or 9), increase the value of the digit you're rounding to by one (+1). Just like before, any remaining digits before the decimal point become zeros, and any after the decimal point drop off. This is called rounding up.
How this Calculator Rounds Numbers
This Rounding Numbers Calculator uses the rounding method called Round Half Away From Zero. Visit the CalculatorSoup Rounding Methods Calculator for an explanation of this and other popular rounding methods.
Rounding Half Away From Zero
Round halfway values away from zero. When the digit to the right is 5 it's at the halfway point and is important in deciding whether to round up or down.
For the following examples let's round to the ones place for values between 2 and 3 where the halfway point is 2.5. In the Rounding Half Away from Zero method, whether you round a positive or a negative number, the absolute value of the result is the same because you're rounding away from 0.
Rounding Positive Numbers
Numbers less than the halfway point between 2 and 3, which is 2.5, round down toward 0. Numbers greater than or equal to the halfway point between 2 and 3 round up away from 0.
- 2.4 rounds down to 2
- 2.48 rounds down to 2
- 2.5 rounds up to 3 halfway, up and away from 0
- 2.52 rounds up to 3
- 2.6 rounds up to 3
Rounding Negative Numbers:
Numbers greater than the halfway point between -3 and -2, which is -2.5, round up toward 0. Numbers less than or equal to the halfway point of -2.5 round down away from 0.
- -2.4 rounds up to -2
- -2.48 rounds up to -2
- -2.5 rounds down to -3 halfway, down and away from 0
- -2.52 rounds down to -3
- -2.6 rounds down to -3
Round to the Nearest Hundred: 3250
- Identify the hundreds digit: the 2 in 3250
- Identify the next smallest place value: the 5 in 3250
- Is that digit greater than or equal to five? Yes, so round up.
- Increase the hundreds digit by one, so 2 becomes 3. Every digit after becomes a zero.
3250 rounded to the nearest hundred is 3300
Round to the Nearest Ten: 323.5
- Identify the tens digit: the 2 in 323.5
- Identify the next smallest place value: the 3 in 323.5
- Is that digit greater than or equal to five? No, so round down.
- The tens digit stays the same at 2. Every digit after becomes a zero. Digits after the decimal point are dropped.
323.5 rounded to the nearest ten is 320
Round to the Nearest Ten: 499
- Identify the tens digit: the first 9 in 499
- Identify the next smallest place value: the second 9 in 499
- Is that digit greater than or equal to five? Yes, so round up.
- The tens digit increases by one. Since 9+1=10, you need to carry the 1 and add it to the digit in the hundreds place. Each digit after becomes a zero.
499 rounded to the nearest ten is 500
Round to the Nearest Tenth: 0.74
- Identify the tenths digit: 7 in 0.74
- Identify the next smallest place value: the 4 in 0.74
- Is that digit greater than or equal to five? No, so round down.
- The tenths digit stays the same at 7. Since the remaining digits are after the decimal point you just drop them.
0.74 rounded to the nearest tenth is 0.7
Round to the Nearest Hundredth: 3.141
- Identify the hundredths digit: the 4 in 3.141
- Identify the next smallest place value: the last 1 in 3.141
- Is that digit greater than or equal to five? No, so round down.
- The hundredths digit stays the same at 4. Drop the digits to the right of 4.
3.141 rounded to the nearest hundredth is 3.14
Related Calculators
To learn how to round a number to the nearest multiple see our Round to Nearest Multiple Calculator. Round to multiples of whole numbers or decimals such as tenths, hundredths, thousandths, etc.
Further Reading
About.com on How to Round Numbers
Math.com has lessons on estimating and rounding.