Domain and Range Calculator
This domain and range calculator helps you find all possible input (domain) and output (range) values for any function. Results are shown in interval notation and include a graph to visualize where the function is defined and what values it can produce.
What Are Domain and Range?
The domain and range describe all valid inputs and outputs of a function, giving insight into its behavior.
Domain:
The set of all possible input values (x-values) for a function. It defines the values of x for which the function is valid. Learn more about functions.
Range:
The set of all possible output values (y-values) that the function produces when evaluated over its domain.

Notation:
- Interval notation: (-∞, +∞), [0, +∞)
- Set-builder notation: {x ∣ x > 0}
- Inequality notation: x > 0, y ≤ 5
How to Use the Calculator
Step 1: Enter the Function
Input your function f(x) in the calculator field.
Step 2: Click "Calculate"
The calculator processes the function and provides the domain and range.
Step 3: Review Results
- Domain and range values in interval notation
- Graphical view showing where the function exists
Input Rules:
- Use lowercase letters only
- Always use x as the variable
Supported Functions:
- Polynomial: x^2 + 3x + 2
- Rational: 1 / (x - 4)
- Root: sqrt(x), cbrt(x)
- Exponential & Logarithmic: e^x, log(x)
Limitations & Syntax Tips:
- Complex numbers are not supported
- Use parentheses accurately
- Exponents: x^3
- Multiplication: 2*x instead of 2x
- Constants: pi, e
Why Use a Domain and Range Calculator?
- Instant Calculation: Quickly get results without manual errors
- Graphical Visualization: See the domain and range on a graph
- Supports Various Functions: Polynomial, rational, root, exponential, logarithmic
- Handles Restrictions Automatically: Division by zero, negative roots, undefined values
Example: Finding Domain and Range
Function:
y = (x + 3) / (10 - x)
Solution:
Domain:
Denominator cannot be zero: 10 - x ≠ 0 → x ≠ 10
✅ Domain: x ∈ (-∞, 10) ∪ (10, ∞)
Range:
y = (x + 3) / (10 - x)
Solving for x: y(10 - x) = x + 3 → x = (10y - 3)/(-y - 1)
Denominator cannot be zero: -y - 1 ≠ 0 → y ≠ -1
✅ Range: y ∈ (-∞, -1) ∪ (-1, ∞)
Interpreting Results:
Domain:
The domain shows all valid x-values. Example: x ∈ (-∞, 10) ∪ (10, ∞) excludes x = 10.
Range:
The range shows all possible outputs. Example: y ∈ (-∞, -1) ∪ (-1, ∞) excludes y = -1.
Continuity, Restrictions & Asymptotes:
- Continuity: No gaps, holes, or breaks in the graph
- Restrictions: Values causing division by zero or negative roots
- Vertical Asymptotes: Function approaches ±∞ at restricted x-values (e.g., x = 10)
- Horizontal Asymptotes: Function approaches a line as x → ±∞ (e.g., y = 1)
- Holes: Points where numerator and denominator are zero, creating gaps
Common Mistakes:
- Forgetting when the denominator equals zero
- Negative values inside a square root for real functions
- Misinterpreting interval endpoints (use parentheses for excluded, brackets for included)
- Ignoring complex or imaginary domains
FAQs:
Can domain and range be the same?
Yes, if the function maps a set onto itself (e.g., f(x) = x):
What if the function is constant?
A constant function always outputs the same value for all inputs. Example: f(x) = c.
References:
- Domain and Range of a Relation – allen.in
- Domain of a Function – Wikipedia
- Domain and Range from Graph – Khan Academy