Integer
Extract the integer part of any real number online for free. Enter any decimal or whole number to find its integer portion instantly.
About This Calculator
The Integer Part Calculator extracts the whole number portion of any real number by removing its fractional/decimal part (truncation toward zero). This free online tool is useful for students learning number theory, programmers working with integer division, and anyone who needs to quickly isolate the integer component of a decimal value.
The calculator uses truncation (the Math.trunc() function), which removes the fractional part of a number without rounding. For positive numbers like 3.14, the result is 3. For negative numbers like -2.7, the result is -2 (truncation toward zero) -- this differs from the floor function (⌊x⌋) which would give -3. This method matches how programming languages like JavaScript, Python, and C++ handle integer truncation.
Common use cases include: simplifying decimal results from division calculations, converting measurements to whole units, preparing data for integer-based algorithms, and teaching the difference between truncation, floor, ceiling, and rounding.
Frequently Asked Questions
What is the integer part of a number?
The integer part (also called truncation or whole number part) of a real number is the integer obtained by removing its fractional/decimal part. For example, the integer part of 3.14 is 3, and the integer part of -2.7 is -2 (truncation toward zero, not floor which would give -3).
What is the difference between integer part and floor?
For positive numbers, the integer part and floor are the same. For negative numbers, the integer part (truncation) moves toward zero while floor moves toward negative infinity. Example: integer part of -3.7 is -3, but floor of -3.7 is -4.
How do you find the integer part without a calculator?
Simply remove everything after the decimal point while keeping the sign. For 7.89, the integer part is 7. For -5.23, the integer part is -5. For numbers without decimals, the integer part is the number itself.
Is the integer part the same as rounding down?
No. Rounding down (floor) always rounds toward negative infinity. The integer part (truncation) rounds toward zero. For positive numbers they match, but for negative numbers they differ: integer part of -2.3 is -2, while floor of -2.3 is -3.
What is the integer part used for in programming?
In programming, extracting the integer part is commonly used for truncating division results (e.g., 7 / 2 = 3.5, integer part = 3), working with array indices, and converting floating-point timestamps into date components. Most languages have a trunc() or int() function.
What is the integer part of zero?
The integer part of zero is zero. Since 0 has no fractional component, truncation leaves it unchanged.
Can I use this calculator for negative numbers?
Yes. The calculator handles negative numbers correctly by truncating toward zero. For example, -3.14 gives -3 as the integer part, not -4 (which would be the floor).