Formula: length × width
Area
Ready
0m²
Compute area for common shapes – real‑time calculation
Founder & CEO, Toolraxy
Faiq Ur Rahman is a web designer, digital product developer, and founder of Toolraxy, a growing platform of web-based calculators and utility tools. He specializes in building structured, user-friendly tools focused on health, finance, productivity, and everyday problem-solving.
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Area is the amount of space inside a two-dimensional shape. It’s measured in square units—square meters (m²), square centimeters (cm²), square inches (in²), or square feet (ft²). Knowing how to calculate area helps you:
Determine how much paint you need for a wall
Figure out the size of a garden bed
Check your geometry homework
Plan furniture placement
Estimate material quantities
This calculator handles 7 different shapes with real-time updates. Change any number, and the area updates instantly.
Memorizing formulas is one thing. Applying them correctly—without calculator errors—is another. Students lose points on tests because of simple multiplication mistakes. DIYers order wrong material quantities because they miscalculated square footage.
This Area Calculator eliminates those errors. Pick your shape. Enter your numbers. Get your answer. The formula is displayed right below your inputs, so you learn as you calculate.
Step 1: Select Your Shape
Choose from 7 options: Rectangle, Square, Circle, Triangle, Parallelogram, Trapezoid, or Ellipse.
Step 2: Choose Your Unit
Select the measurement unit your dimensions are in: meters, centimeters, inches, or feet.
Step 3: Enter Dimensions
Type your measurements in the input fields. All fields update in real-time.
Step 4: Read Your Result
The area appears instantly with the correct square unit. The formula is shown below the inputs.
Step 5: Try Examples
Click “Load Example” to see typical values for your selected shape.
Step 6: Clear and Repeat
Click “Clear” to reset all fields for a new calculation.
Multiply length by width. A rectangle 5 meters long and 3 meters wide = 15 m².
Multiply side by itself (side²). A square with 4-meter sides = 16 m².
Multiply π (3.14159) by the radius squared. A circle with 3-meter radius = 28.27 m².
Multiply base by height, then divide by 2. A triangle with 6m base and 4m height = 12 m².
Multiply base by height (perpendicular height, not slanted side). A parallelogram with 5m base and 2m height = 10 m².
Average the two parallel bases, multiply by height. Bases 4m and 6m, height 3m = 15 m².
Multiply π by semi-axis A times semi-axis B. Axes 5m and 3m = 47.12 m².
Shape: Rectangle
Dimensions: 4m height × 5m width
Area: 20 m²
Paint needed: 1 liter covers ~10 m² → 2 liters
Shape: Circle
Radius: 2 meters
Area: 12.57 m²
Mulch needed: 12.57 m² at 5cm depth = 0.63 cubic meters
Shape: Trapezoid
Bases: 1.2m and 0.8m, Height: 1.5m
Area: 1.5 m²
Tablecloth size: Slightly larger than 1.5 m²
Shape: Ellipse
Semi-axes: 0.6m and 0.4m
Area: 0.75 m²
Glass needed: Approximately 0.75 m²
7 Shapes Supported – Covers most common geometry needs
Real-Time Updates – Results change as you type
Formula Display – Learn while you calculate
Multiple Units – Meters, centimeters, inches, feet
Example Values – One click loads typical dimensions
Mobile-Friendly – Works on phones and tablets
Completely Free – No signup, no ads, no limits
| User | Why It Helps |
|---|---|
| Students | Check homework, study for tests |
| Teachers | Demonstrate formulas in class |
| DIY Homeowners | Plan projects, estimate materials |
| Contractors | Quick on-site calculations |
| Gardeners | Plan planting beds and layouts |
| Artists | Calculate canvas or frame sizes |
| Anyone | Quick math without mental errors |
1. Confusing Radius with Diameter
Circle area uses radius (half the diameter). If you have diameter, divide by 2 first before entering.
2. Using Slanted Height for Parallelogram
Parallelogram area uses perpendicular height—a straight vertical line, not the slanted side length.
3. Mixing Units
All dimensions must be in the same unit. Don’t mix meters and centimeters. Use the unit selector to match your measurements.
4. Forgetting the ½ in Triangle Formula
Triangle area is half of base × height. Our calculator handles this automatically, but when checking manually, don’t forget the ½.
5. Entering Negative Numbers
Dimensions can’t be negative. The calculator shows “Invalid” if you enter negative values.
6. Misreading Square Units
Area results are in square units. 5 meters × 3 meters = 15 square meters (m²), not 15 meters.
Base/Height Triangles Only – Doesn’t calculate triangles from three side lengths (Heron’s formula)
No Irregular Polygons – For shapes with 5+ sides, use multiple calculations
Radius-Only Circles – Enter radius, not diameter (divide diameter by 2 first)
No Unit Conversion – Numbers stay the same when switching units (assumes inputs are in selected unit)
No Cost Calculation – Pure area only, no material pricing
2D Only – Doesn’t calculate volume or surface area of 3D objects
Perimeter measures the distance around a shape—the boundary length. Area measures the space inside. A rectangle with 5m × 3m has perimeter 16m (2 × (5+3)) and area 15m². They’re different measurements for different purposes. Use perimeter for fencing, framing, or borders. Use area for flooring, painting, or covering.
π (pi) is the ratio of a circle’s circumference to its diameter—approximately 3.14159. It appears in circle area (πr²) because circles are curved shapes that don’t fit neatly into square grids. Pi is constant for all circles, which is why the formula works universally.
If you only know a circle’s diameter (the full width), divide by 2 to get radius. Example: diameter 10m → radius 5m → area = π × 5² = 78.54 m². Our calculator uses radius, so remember this conversion.
Area is always expressed in square units because you’re measuring two dimensions multiplied together. 5 meters × 3 meters = 15 square meters (written as 15 m²). This is different from linear measurements (meters) or cubic measurements (m³ for volume).
1 square meter = 10,000 square centimeters = 1,550 square inches = 10.76 square feet. If your project requires different units, calculate in one system then convert. Our calculator keeps units consistent—your inputs and outputs match.
If you know all three sides of a triangle but not the height, use Heron’s formula: s = (a+b+c)/2, then Area = √(s(s-a)(s-b)(s-c)). This calculator doesn’t include it, but it’s useful for triangles where height is hard to measure.
Multiply length by width. Example: length 5m, width 3m = 15 m². Select “Rectangle” in the shape selector, enter your numbers, and get instant results.
Circle area = π × r², where r is radius (half the diameter). π is approximately 3.14159. Enter your radius in the circle option.
Multiply base by height, then divide by 2. Example: base 6m, height 4m = 12 m². Select “Triangle” and enter your base and height.
A parallelogram has slanted sides; rectangle has right angles. But both use the same area formula: base × perpendicular height.
Add the two parallel bases, divide by 2, then multiply by height. Formula: ½ × (a + b) × h. Select “Trapezoid” and enter your values.
Yes. Ellipse area = π × a × b, where a and b are the semi-axes (half the width and half the height). Select “Ellipse” and enter both semi-axes.
Meters (m), centimeters (cm), inches (in), and feet (ft). Results are shown in square units (m², cm², in², ft²).
Yes. It uses standard geometric formulas and displays results to 4 decimal places. Use it to check your work, but always show your steps on assignments.
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