Scientific precision, live in your browser
Máy tính diện tích bề mặt
Instant formulas, live results, and step-by-step breakdowns for every 3D shape.
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Chọn máy tính
Each calculator shows the formula, intermediate values, units, and references so results are easy to check.
Máy tính diện tích hình cầu
SA = 4πr²Máy tính hình lập phương
SA = 6a²Máy tính diện tích hình trụ
SA = 2πr(r + h)Máy tính diện tích hình nón
SA = πr(r + √(r² + h²))Máy tính hình hộp chữ nhật
SA = 2lw + 2lh + 2whMáy tính lăng trụ tam giác
SA = PL + 2BMáy tính hình chóp
SA = base + lateral facesMáy tính ellipsoid
SA ≈ 4π[((a^1.6b^1.6 + a^1.6c^1.6 + b^1.6c^1.6) / 3)]^(1/1.6)Máy tính viên nang
SA = 4πr² + 2πrhMáy tính hình xuyến
SA = 4π²RrMáy tính nón cụt
SA = π(R² + r²) + π(R + r)√((R - r)² + h²)Máy tính chỏm cầu
SA = 2πRh + πr²Formula-first calculators
Every result includes the exact formula, substituted values, and a readable step-by-step calculation.
Unit-aware results
Switch between metric and imperial units without leaving the page, including square-unit conversion guidance.
Built for learning
Labelled diagrams, examples, references, and related calculators help users understand the geometry.
Surface area basics
Calculate surface area with confidence
Surface area measures the total exposed area on the outside of a three-dimensional shape. Students use it to check geometry homework, teachers use it to explain nets and formulas, and builders use it to estimate paint, wrapping, insulation, coating, or material coverage. A sphere uses a radius-only formula, a cylinder combines two circular bases with one curved side, and prisms add the areas of matching faces. More specialized shapes, such as ellipsoids, torus forms, capsules, and conical frustums, need formulas that are easy to misread when copied from a textbook. This site keeps the calculator, diagram, formula, and worked steps together so the result is fast but still auditable.
Choose a calculator above, enter positive dimensions, and compare the result with the formula breakdown. For adjacent topics, use the related-shape links on each calculator page or read the articles on derivations, paint coverage, and unit conversion.
FAQ
Surface area questions
What is surface area?
Surface area is the total outside area of a three-dimensional object. It is measured in square units such as m², cm², ft², or in².
How do these calculators work?
Each calculator applies a published geometry formula, substitutes your dimensions, and shows the intermediate steps so the result can be checked by hand.
Can I use different units?
Yes. Choose meters, centimeters, millimeters, feet, inches, or kilometers. Results are shown in the matching square unit.
Are calculations stored?
No. Calculations run in your browser and are not saved as personal history.
Which calculator should I choose?
Choose the page that matches the shape. If the object is a combination of shapes, calculate each part and add the areas that are exposed.
Learn more
Bài viết
Vì sao hình cầu có diện tích 4πr²
Calculate and visualize surface area for common 3-D shapes with clear formulas, examples, and citations.
Diện tích nón và nón cụt từ hình khai triển
Calculate and visualize surface area for common 3-D shapes with clear formulas, examples, and citations.
Ước tính sơn từ diện tích bề mặt
Calculate and visualize surface area for common 3-D shapes with clear formulas, examples, and citations.