What format does each line need to be in?

"a/b", where a and b are whole numbers (either may be negative), separated by a single forward slash, like "15/3".

What happens if a fraction isn't a whole number, like 7/2?

The whole conversion is rejected with an error naming that specific line, rather than rounding or truncating to a nearby integer.

Why reject instead of rounding?

Silently rounding could hide a mistake in your input data. Since this tool's purpose is recovering exact integers, an inexact fraction is treated as an error rather than approximated.

What about a zero denominator?

A fraction like "5/0" is rejected outright, since division by zero is undefined.

Fraction to Integer Converter - Divide a/b to a Whole Number

Overview

Introduction

This tool takes a list of "a/b" fractions and divides each one out to recover a plain integer, but only when the division is exact.

It's the reverse of the Integer to Fraction Converter, and it treats an inexact result as an error rather than quietly rounding it away.

What Is Fraction to Integer Converter?

A converter that takes a list of fraction strings, one per line, and outputs the integer each one equals, whenever the numerator divides evenly by the denominator.

If any line's fraction isn't a whole number, the entire conversion fails with an error identifying that line, rather than producing a partially rounded result set.

How Fraction to Integer Converter Works

Each line is parsed into a numerator and denominator using a strict "a/b" pattern, allowing an optional "-" on either part.

The tool checks that the denominator isn't zero, then checks whether the numerator is evenly divisible by the denominator using the remainder operator.

If it divides evenly, the quotient is reported; if not, the whole batch fails with an error identifying that specific line as not a whole number.

When To Use Fraction to Integer Converter

Use it to check whether a set of fractions all reduce to whole numbers, and to recover those integers when they do.

It's useful for validating output from the companion Integer to Fraction Converter, or for checking manual fraction-reduction homework.

Often used alongside Integer to Fraction Converter and Ordinal to Integer Converter.

Features

Advantages

Never silently rounds or truncates; an inexact fraction is always flagged rather than hidden.
Clearly identifies which specific line caused a failure in a multi-line batch.

Limitations

Rejects the entire batch on the first non-whole-number fraction rather than skipping just that line, which may not suit workflows that want partial results.
Only accepts the plain "a/b" text format; mixed numbers (like "2 1/2") aren't supported.

Examples

Evenly divisible fraction

Input

15/3

Output

Not a whole number

Invalid input

7/2

Parser error

Error: not a whole number

7 divided by 2 is 3.5, which isn't a whole number, so this line is rejected instead of being rounded.

Corrected version

8/2

Best Practices & Notes

Best Practices

If you expect some fractions in your list to legitimately not be whole numbers, filter those out before running the batch, since one bad line rejects the whole conversion.

Developer Notes

Divisibility is checked with `numerator % denominator !== 0` rather than comparing a floating-point division result, avoiding any floating-point rounding edge cases when determining whether the fraction is exactly whole.

Fraction to Integer Converter Use Cases

Validating that a list of fractions all reduce to whole numbers
Recovering integers from fractions generated by the Integer to Fraction Converter
Checking manual fraction-reduction homework or calculations

Common Mistakes

Expecting an inexact fraction like 7/2 to be rounded to 4 or 3 instead of rejected.
Using a zero denominator, which is always invalid regardless of the numerator.

Tips

Pair this with the Integer to Fraction Converter to round-trip integers through a fraction and back.

Fraction to Integer Converter