Area Calculator UK 2025

Calculate area of 2D shapes: square, rectangle, circle, triangle and trapezoid. Get results in cm² and m². Perfect for GCSE maths, flooring, garden planning and DIY projects.

Select Shape and Calculate Area

Shape Type

Side Length (cm)

How to Use the Area Calculator

Select Shape: Choose the 2D shape you want to calculate from the dropdown menu (square, rectangle, circle, triangle, or trapezoid).
Enter Measurements: Input the required measurements in centimetres. Different shapes need different inputs - squares need one side, rectangles need length and width, circles need radius, triangles need base and height.
Calculate: Click "Calculate Area" to see your results instantly.
View Results: The calculator displays area in square centimetres (cm²) and automatically converts to square metres (m²). For shapes like squares, rectangles and circles, it also shows the perimeter.
See Formula: Each result includes the mathematical formula used, helpful for GCSE maths homework and understanding the calculation method.

Area Formulas for 2D Shapes

Square Area

Area = side² (side × side)

A square has all four sides equal. If each side is 5cm, the area is 5 × 5 = 25 cm². The perimeter is 4 × 5 = 20cm. Common in GCSE maths and useful for tile calculations.

Rectangle Area

Area = length × width

Multiply the length by the width. For example, a room 10m long and 5m wide has an area of 50 m². The perimeter is 2 × (10 + 5) = 30m. Essential for flooring, carpet and paint calculations.

Circle Area

Area = π × radius²

The radius is the distance from the centre to the edge. For a circle with radius 5cm, the area is approximately 78.54 cm². The circumference (perimeter) is 2 × π × radius ≈ 31.42cm. Useful for circular ponds, patios or pizza calculations.

Triangle Area

Area = ½ × base × height

The base is any side, and the height is the perpendicular distance from that base to the opposite vertex. For a triangle with base 8cm and height 6cm, the area is ½ × 8 × 6 = 24 cm². Commonly used in GCSE maths and roof calculations.

Trapezoid Area

Area = ½ × (base1 + base2) × height

A trapezoid has two parallel sides of different lengths. Add both parallel sides, multiply by the perpendicular height, then divide by 2. For bases of 8cm and 5cm with height 4cm, the area is ½ × (8 + 5) × 4 = 26 cm².

Frequently Asked Questions

To calculate the area of a rectangle, multiply length by width. For example, a rectangle 10cm long and 5cm wide has an area of 10 × 5 = 50 cm². The calculator does this automatically when you enter the dimensions. This is the most common calculation for UK rooms, flooring and garden areas.

The formula for circle area is: Area = π × radius². For example, a circle with radius 5cm has an area of approximately 78.54 cm². You only need to enter the radius and the calculator will compute the area using π (pi ≈ 3.14159). The circumference (perimeter) is calculated as 2πr.

To convert square centimetres (cm²) to square metres (m²), divide by 10,000. For example, 50,000 cm² = 5 m². The area calculator automatically displays results in both cm² and m² for convenience when planning flooring, painting or garden projects. Remember: 1 m² = 10,000 cm² = 1,000,000 mm².

The triangle area formula is: Area = ½ × base × height. For example, a triangle with base 8cm and height 6cm has an area of ½ × 8 × 6 = 24 cm². Enter the base and perpendicular height into the calculator. The height must be at right angles to the base - not the slant height.

Sarah Collins

Mathematics Educator & GCSE Specialist

PGCE Mathematics BSc Mathematics NCETM Accredited QTS

Sarah is a qualified mathematics teacher with over 15 years of experience teaching GCSE and A-Level mathematics in UK secondary schools. She holds Qualified Teacher Status (QTS) and is accredited by the National Centre for Excellence in the Teaching of Mathematics. Sarah specialises in making mathematical concepts accessible for students and has developed curriculum resources used across England and Wales. She regularly contributes educational content on geometry, area calculations, and practical mathematics applications.

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💡 Pro Tips for Accurate Results ▼

Double-check your input values before calculating
Use the correct unit format (metric or imperial)
For complex calculations, break them into smaller steps
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📊 Understanding Your Results ▼

Our Area Calculator provides:

Instant calculations - Results appear immediately
Accurate formulas - Based on official UK standards
Clear explanations - Understand how results are derived
2025/26 updated - Using current rates and regulations

❓ Common Questions ▼

Is this calculator free?

Yes, all our calculators are 100% free to use with no registration required.

Are the results accurate?

Our calculators use verified formulas and are regularly updated for accuracy.

Can I use this on mobile?

Yes, all calculators are fully responsive and work on any device.

❓ People Also Ask

Yes, our calculators use verified formulas and are regularly updated with current UK rates and regulations. Results are provided for guidance - always consult professionals for major financial decisions.

Absolutely! All our calculators are fully responsive and work perfectly on smartphones, tablets, and desktops. No app download needed.

We update all calculators with new rates as soon as they're announced - typically at the start of each tax year (April) or when significant changes occur.