# Write a PHP program to print sum of digits

In this program, you will find the Sum of digits program using for loop, while loop, do-while, and HTML form. The Sum of digits is the addition of all individual digits. For example, the sum of digits of 234 is 2+3+4=9

## Program to find sum of digit using for loop In PHP

``````
<?php
\$number=345;
\$sum=0;
for(\$i=0;\$i<=strlen(\$number);\$i++)
{
\$sum=\$sum+\$number%10;
\$number/=10;
}
echo"sum of digit 345 is \$sum";
?>
``````

## output

`sum of digit 345 is 12`

## Program to find sum of digit using while loop In PHP

``````
<?php
\$number=123;
\$sum=0;
while(\$number>0)
{
\$sum=\$sum+\$number%10;
\$number/=10
}
echo"sum of digit 123 is \$sum";
?>
``````

## output

`sum of digit 123 is 6`

## Program to find sum of digit using do-while loop In PHP

``````
<?php
\$number=123;
\$sum=0;
do
{
\$sum=\$sum+\$number%10;
\$number/=10;
}
while(\$number>0);
echo"sum of digit 123 is \$sum";
?>
``````

## output

`sum of digit 123 is 6`

## Find sum of digit using HTML form In PHP

``````
<!DOCTYPE html>
<html lang="en">
<title>Write a program to find sum of digit in php</title>
<body>
<form>
<label for="number">Enter the number:</label> <input type="number" name="SumDigit">
<input type="submit" value="submit" name="click"></br></br>
</form>
</body>
</html>
<?php
if(isset(\$_GET["click"]))
{
\$number=\$_GET['SumDigit'];
\$num=\$number;
\$sum=0;
for(\$i=0;\$i<=strlen(\$number);\$i++,\$number/=10)
{
\$sum=\$sum+\$number%10;
}
echo"sum of digit \$num is \$sum";
}
?>
``````

## output

### Logic to find sum of digits in PHP

1. Take the number and store it in a variable `number`.
2. Find the last digits using modulus division `\$number%10`.
3. Add the last digit into variable `sum`.
4. repeat step 2 and 3 until the value of `number` become 0.