# How to Round to Significant Figures in Excel

To round to significant figures in Excel, you can use a combination of the ROUND and SIGNIFICANT functions. Here's a step-by-step guide on how to do this:

- Open Excel and enter your data in a cell. For example, let's say you have the number 123.456 in cell A1 and you want to round it to 3 significant figures.
- In another cell, let's say B1, type the following formula:
`=ROUND(A1, 3-1-INT(LOG10(ABS(A1))))`

- Press Enter, and you will see the rounded number in cell B1.

Here's a breakdown of the formula:

`LOG10(ABS(A1))`

calculates the logarithm base 10 of the absolute value of the number in cell A1.`INT(LOG10(ABS(A1)))`

returns the integer portion of the logarithm, which represents the number of digits before the decimal point.`3-1-INT(LOG10(ABS(A1)))`

calculates the number of decimal places to round to, based on the desired number of significant figures (3 in this case).`ROUND(A1, 3-1-INT(LOG10(ABS(A1))))`

rounds the number in cell A1 to the calculated number of decimal places.

## Example

Let's say you have the following numbers in column A:

```
A
1 123.456
2 0.01234
3 56789
```

You want to round these numbers to 3 significant figures. In column B, you'll use the formula mentioned above:

```
B
1 =ROUND(A1, 3-1-INT(LOG10(ABS(A1))))
2 =ROUND(A2, 3-1-INT(LOG10(ABS(A2))))
3 =ROUND(A3, 3-1-INT(LOG10(ABS(A3))))
```

After entering the formulas, you'll get the following rounded numbers:

```
B
1 123
2 0.0123
3 56800
```

These numbers are now rounded to 3 significant figures.

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