# Round to the nearest tenth?

Rounds any number to the nearest tenth (one decimal place) in exact decimals, and says which digit decides.

- Page: https://www.acalculator.org/math/round-to-the-nearest-tenth-calculator
- JSON spec: https://www.acalculator.org/math/round-to-the-nearest-tenth-calculator.json
- Version: c64e076b8c2a

## Default answer

Example with the default inputs (Number to round 18.379): 18.379 rounded to the nearest tenth is 18.4.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| number | Number to round | The number to round, as you would write it. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| rounded | Rounded number | The number rounded to the nearest tenth; halves round away from zero. |
| rule | Why | The digit to the right of the tenths place, and what it does. |
| typed | Number | The number to round, with every digit as typed, so the answer does not round it first. |

## Method

Look at the hundredths digit: 5 or more rounds the size of the number up to the next tenth; less than 5 keeps the tenths digit. Every digit to the right is dropped.

## Assumptions

- The number is taken as the decimal it is written as, so an exact halfway value is a true tie.
- Halves round away from zero (round half up on the size of the number): a negative number rounds like its size, with the minus sign kept.

## Worked examples

1. number = 18.379 gives rounded = 18.4, rule = The hundredths digit is 7, which is 5 or more, so the tenths digit goes up by 1.. Source: OpenStax, Prealgebra 2e, section 5.1 Decimals (round 18.379 to the nearest tenth: 18.4), https://openstax.org/books/prealgebra-2e/pages/5-1-decimals (retrieved 2026-11-01).
2. number = 3.14159 gives rounded = 3.1, rule = The hundredths digit is 4, which is less than 5, so the tenths digit stays.. Source: OpenStax, Prealgebra 2e, section 5.1 Decimals (round 18.379 to the nearest tenth: 18.4), https://openstax.org/books/prealgebra-2e/pages/5-1-decimals (retrieved 2026-11-01).
3. number = 1.45 gives rounded = 1.5. Source: OpenStax, Prealgebra 2e, section 5.1 Decimals (round 18.379 to the nearest tenth: 18.4), https://openstax.org/books/prealgebra-2e/pages/5-1-decimals (retrieved 2026-11-01).
4. number = -2.25 gives rounded = −2.3. Source: OpenStax, Prealgebra 2e, section 5.1 Decimals (round 18.379 to the nearest tenth: 18.4), https://openstax.org/books/prealgebra-2e/pages/5-1-decimals (retrieved 2026-11-01).
5. number = 9.96 gives rounded = 10.0. Source: OpenStax, Prealgebra 2e, section 5.1 Decimals (round 18.379 to the nearest tenth: 18.4), https://openstax.org/books/prealgebra-2e/pages/5-1-decimals (retrieved 2026-11-01).
6. number = -0.04 gives rounded = 0.0. Source: OpenStax, Prealgebra 2e, section 5.1 Decimals (round 18.379 to the nearest tenth: 18.4), https://openstax.org/books/prealgebra-2e/pages/5-1-decimals (retrieved 2026-11-01).

## FAQ

### How do you round to the nearest tenth?

Look at the hundredths digit, the second digit after the decimal point. If it is 5 or more, add 1 to the tenths digit. If it is less than 5, keep the tenths digit. Then drop every digit after the tenths place. 18.379 has a 7 in the hundredths place, so it rounds to 18.4.

### What is the tenths place?

It is the first digit after the decimal point. In 18.379 the tenths digit is 3, the hundredths digit is 7, and the thousandths digit is 9.

### Does the third decimal digit matter?

No. Only the hundredths digit decides. 2.349 rounds to 2.3, because its hundredths digit is 4. The 9 after it does not push the 4 up first.

### What is 9.96 rounded to the nearest tenth?

10.0. The hundredths digit is 6, so the 9 in the tenths place goes up by 1. That carries into the ones place, and 9 becomes 10.

### How do negative numbers round?

Round the size of the number and keep the minus sign. −2.25 rounds to −2.3, the same way 2.25 rounds to 2.3. So a half rounds away from zero.

### Why does the answer show a zero at the end, such as 10.0?

The zero shows that the number is correct to one decimal place. 10.0 and 10 have the same value.

## Sources

- OpenStax, Prealgebra 2e, section 5.1 Decimals (how to round decimals; 18.379 to the nearest tenth is 18.4). Retrieved 2026-11-01. https://openstax.org/books/prealgebra-2e/pages/5-1-decimals