Domain and Range Calculator

Find the domain and range for common function families such as linear, quadratic, square-root, reciprocal, logarithmic, and exponential functions.

FunctionsDomainRange

Calculate

Function family
Coefficient a
h / horizontal shift
k / vertical shift
Base b for exponential
Please enter valid values.

What this calculator teaches

Domain means all input x-values that are allowed. Range means all output y-values the function can produce.

This calculator focuses on the common parent functions students meet in Algebra 2 and Precalculus. It shows how shifts and coefficients change restrictions.

Formula & Symbols

ConceptFormulaMeaning
Domainx values allowedInputs that do not break the function.
Rangey values possibleOutputs produced by the function.
Quadratic vertexy=a(x-h)^2+kThe vertex is (h,k), so range depends on whether a is positive or negative.

Step-by-Step Examples

Example 1
Square-root function
  • For y = √(x - 3) + 2, the expression under the radical must be nonnegative.
  • x - 3 ≥ 0, so x ≥ 3.
  • The smallest output is 2.
✓ Domain: x ≥ 3; Range: y ≥ 2.
Example 2
Reciprocal function
  • For y = 1/(x - 4) + 2, the denominator cannot be zero.
  • x - 4 ≠ 0, so x ≠ 4.
  • The horizontal asymptote is y = 2, so y ≠ 2.
✓ Domain: x ≠ 4; Range: y ≠ 2.

Where students use this

🎓
High school and college
Use the tool to check homework and understand each step.
📊
Data and modeling
Connect formulas to tables, graphs, and real values.
🧪
Science and engineering
Use math results inside physics, chemistry, and engineering problems.
💻
Computer science
Apply the same logic to algorithms, systems, and numerical work.

Common Mistakes to Avoid

⚠️
Confusing domain and range

Domain is about x-values. Range is about y-values.

⚠️
Ignoring the denominator

A denominator cannot equal zero, so reciprocal functions exclude one x-value.

⚠️
Forgetting the vertex

For quadratics, the range starts or ends at the vertex y-value k.

Frequently Asked Questions

What is domain in simple words?
The domain is the list or interval of all x-values you are allowed to plug into the function.
What is range in simple words?
The range is the list or interval of all y-values the function can output.
Why do square roots restrict domain?
In real-number math, the expression inside an even root cannot be negative.
Why do logarithms restrict domain?
The input of a logarithm must be positive.
Can a linear function have all real domain and range?
Yes, a nonhorizontal linear function has domain all real numbers and range all real numbers.

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Formula Explorer connections

Interpretation: This formula describes an algebraic relationship among variables, functions, equations, roots or sequences. Assumption: Respect the expression’s domain and excluded values. Check roots in the original equation because transformations can introduce extraneous solutions.

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