Height Length Width Calculator
Enter the three dimensions of a rectangular space or box to calculate volume, surface area, base area, and more.
What this height length width calculator does
A height length width calculator helps you quickly measure 3D space. If you know the length, width, and height of a rectangular object (like a room, shipping box, fish tank, storage bin, or concrete form), you can instantly compute key measurements without doing manual math.
This tool calculates:
- Volume (how much space is inside)
- Surface area (total outside area)
- Lateral area (side wall area)
- Base area (footprint area)
- Base perimeter (outline around the base)
- Space diagonal (corner-to-corner distance through the box)
Formulas used by the calculator
For a rectangular prism with length L, width W, and height H:
- Base Area = L × W
- Volume = L × W × H
- Lateral Area = 2 × (L + W) × H
- Surface Area = 2 × (LW + LH + WH)
- Base Perimeter = 2 × (L + W)
- Space Diagonal = √(L² + W² + H²)
How to use it correctly
1) Measure all three dimensions
Use the same unit for each input. For example, all in feet or all in centimeters. Mixing units (like inches for length and feet for width) gives wrong results.
2) Choose your unit and precision
Pick the unit that matches your measurements and select decimal places based on how precise you need the result. Construction jobs often use fewer decimals; engineering tasks may use more.
3) Click Calculate
The calculator instantly returns all core values in matching squared and cubed units, plus a liters estimate for volume comparison.
Practical examples
Room volume for airflow or HVAC
If a room is 5 m long, 4 m wide, and 2.8 m high, volume is 56 m³. That value helps with ventilation planning, dehumidifier sizing, and energy calculations.
Shipping and storage boxes
In logistics, box volume determines packing efficiency and freight cost. Surface area can also estimate wrapping material and insulation needs.
Aquariums and tanks
Tank dimensions are often in centimeters or inches, but people want a liters estimate. This tool converts the cubic volume into liters so you can estimate water capacity faster.
Common mistakes to avoid
- Entering zero or negative dimensions
- Using different units for different sides
- Confusing area units (m²) with volume units (m³)
- Rounding too early during planning calculations
- Using outside dimensions when you need inside capacity
Quick unit notes
Length is measured in simple units (m, cm, ft). Area is squared units (m², ft²). Volume is cubed units (m³, ft³). Cubed units grow quickly, so double-check decimal points in your entries.
FAQ
Can I use decimals?
Yes. The calculator accepts decimal values for all three dimensions.
Is this only for boxes?
It is designed for rectangular prisms. That includes most rooms, cartons, bins, tanks, and cabinets with straight edges.
Why does volume look very large?
Cubic units compound fast. Even moderate dimensions can create large numbers, especially when using larger base units such as feet or meters.