Rounding Calculator

1. Enter the number you want to round.
2. Set the decimal places: 0 for a whole number, 2 for cents, or a negative value for tens.
3. Choose a rounding method.
4. Read the rounded value, the place used, and the change from the original.

Here is what each result means:

Rounding replaces a number with a nearby, simpler one to a chosen place. If the digit after that place is 5 or more, you round up; if it is 4 or less, you round down. So 3.14159 to two decimals is 3.14, and 47 to the nearest ten is 50.

Rounding keeps numbers readable and matches the precision you actually need. Money is rounded to cents, measurements to sensible units, and statistics to a few significant places. The one tricky case is a value ending in exactly five, which is where the different methods differ.

It scales the number by a power of ten for the chosen place, rounds by your method, then scales back.

1. Shift the decimal point to the rounding place.
2. Apply the chosen rule to the digit being dropped.
3. Shift the decimal point back for the final value.

To round to a number of meaningful digits instead of decimal places, a significant-figures approach is used; the percentage calculator shows rounding in everyday percentages.

Round 3.14159 to two decimal places, and 1274 to the nearest ten.

Calculation: for 3.14159, the third decimal is 1, which is 4 or less, so the value rounds down to 3.14. For 1274, the units digit is 4, so it rounds down to 1270. Had the units digit been 5 or more, it would round up to 1280.

The place you round to changes how much detail you keep.

Use positive places for decimals and negative places for tens, hundreds and beyond.

The methods agree except when a value ends in exactly five, where they split.

Half up is taught in schools; half to even, also called banker rounding, avoids a slight upward bias over many values and is common in finance and statistics.

The Rounding Place

Rounding to fewer places changes the number more. The nearest hundred moves a value further than the nearest whole.

The Method for a Half

When the dropped digit is exactly five, the method decides the direction, so half up and half to even can differ.

The Sign of the Number

Ceiling and floor treat negatives differently, since ceiling moves toward positive and floor toward negative.

Money and Billing

Round to two decimal places for cents, or to whole units for estimates.

Reporting Results

Round measurements and statistics to a sensible precision for a report.

Checking a Method

Compare half up with banker rounding when exact halves matter.

1. Rounding Step by Step

Round once, to the final place. Rounding 2.449 to 2.45 then to 2.5 gives a wrong answer.

2. Using the Wrong Method for Money

Finance often needs banker rounding, not simple half up. Match the method to the rules.

3. Confusing Places and Significant Figures

Two decimal places is not the same as two significant figures. Decide which you need.

4. Forgetting Negative Signs

Ceiling and floor move in fixed directions, which flips your expectation for negative numbers.

5. Dropping Needed Precision

Rounding too early in a long calculation can build up error. Round at the end.

The rounding is exact for the method chosen; only tiny floating-point effects can appear.

Look at the digit just after the place you are rounding to. If it is 5 or more, round up; if it is 4 or less, round down. So 3.14159 to two decimals is 3.14.

It is the standard method taught in schools: a digit of exactly 5 rounds the previous digit up. So 2.5 becomes 3 and 4.5 becomes 5. This tool uses it by default.

Also called round half to even, it rounds an exact half to the nearest even digit. So 2.5 becomes 2 and 3.5 becomes 4. It avoids a slight upward bias over many numbers and is common in finance.

Use negative decimal places: -1 for the nearest ten, -2 for the nearest hundred. So 1274 to the nearest ten is 1270, and to the nearest hundred is 1300.

Rounding moves to the nearest value, up or down. Truncating simply cuts off the extra digits without rounding, so 3.19 truncated to one decimal is 3.1, not 3.2.

They only differ when a value ends in exactly five. Half up rounds it up, half to even rounds to the nearest even digit, and ceiling or floor always go one direction.

Many financial and accounting systems use banker rounding to avoid bias over many transactions. Check the rules that apply to your case, since some contexts require half up.

No. Two decimal places keeps two digits after the point, while two significant figures keeps the first two meaningful digits. For 0.00456 they give very different results.

No. The calculation runs in your browser and nothing you enter is stored or sent anywhere, unless you choose Save, which keeps the result only on this device.

• Rounding (Wikipedia).
• Rounding numbers explained (Maths Is Fun).
• Rounding methods (Maths Is Fun).