Formula Used
Imperial slab self load: unit weight × thickness ÷ 12.
Metric slab self load: unit weight × thickness ÷ 1000.
Total dead load: slab self load + finishes + ceilings + partitions + equipment.
Reduced live load: live load × (1 − reduction ÷ 100).
Service area load: total dead load + reduced live load.
Factored area load: dead factor × dead load + live factor × live load.
Total load: area load × tributary area.
Beam line load: area load × tributary width.
How to Use This Calculator
- Select imperial or metric units before entering values.
- Enter the tributary floor or roof area.
- Add slab thickness and material unit weight.
- Enter all superimposed dead load components separately.
- Enter the occupancy live load from your design criteria.
- Add any permitted live load reduction percentage.
- Set load factors required by your project method.
- Press calculate and export the result if needed.
Example Data Table
| Case |
Area |
Slab |
Dead load |
Live load |
Factored area load |
| Office floor |
1000 sq ft |
6 in concrete |
100 psf |
50 psf |
200 psf |
| Light storage |
1500 sq ft |
125 mm concrete |
4.5 kPa |
4.8 kPa |
13.08 kPa |
| Roof check |
800 sq ft |
Metal deck |
22 psf |
20 psf |
58.4 psf |
Construction Load Planning
Live load and dead load checks support safe framing decisions. Dead load is the permanent weight of the structure. It includes concrete, steel, timber, finishes, ceilings, services, fixed partitions, and fixed equipment. Live load is different. It represents movable use loads. People, furniture, stored items, carts, and temporary work platforms are common examples.
Why These Loads Matter
A floor may look simple, yet it carries many layers. A slab has self weight. Finishes add more demand. Ceilings and ducts add steady load. Partitions may move during future fit-outs. The live load changes with the room use. An office, corridor, classroom, roof, and storage room rarely share the same design value. Good calculations keep these items visible.
Using Area Loads
Most early checks use area loads. The calculator treats dead and live actions as pressure over a tributary area. In imperial mode, values use psf and pounds. In metric mode, values use kPa and kilonewtons. Slab self weight is calculated from thickness and unit weight. Other dead load items are added as superimposed values. Then the live load is reduced when a permitted reduction is entered.
Service and Factored Results
Service load helps with deflection, vibration, and general comparisons. It is the working total before strength factors. Factored load is used for strength checks. The common expression is factor D times dead load plus factor L times live load. The factors must match the governing code and project method. This tool lets you change both factors.
Beam Tributary Checks
A beam often receives load from a strip of floor. The strip width is the tributary width. Multiplying area load by this width gives line load. Multiplying line load by span gives a simple span total. This is useful for preliminary beam sizing. It is not a substitute for shear, moment, bearing, lateral stability, or connection design.
Practical Use
Use measured dimensions and reliable material weights. Separate permanent and movable items. Avoid hiding heavy equipment inside a general allowance. Record assumptions before exporting results. Compare outputs with local building code tables. Ask a licensed professional to review final structural design. Keep saved reports with drawings, schedules, and revision notes so future changes remain easy to trace for teams later.
FAQs
What is dead load?
Dead load is the permanent weight of a building element. It includes structural members, slabs, finishes, ceilings, fixed services, fixed partitions, and fixed equipment.
What is live load?
Live load is the movable load from use and occupancy. It may include people, furniture, stored items, movable equipment, and temporary construction activity.
Can this calculator replace code design?
No. It supports preliminary calculation and documentation. Final structural design should follow local codes and should be checked by a qualified professional.
What units should I enter?
Use psf, pcf, inches, pounds, and feet in imperial mode. Use kPa, kN/m³, millimeters, kilonewtons, and meters in metric mode.
What is tributary area?
Tributary area is the floor or roof area carried by a member. It helps convert area loads into total loads on beams, columns, or supports.
What is live load reduction?
Live load reduction lowers the design live load when allowed by code. It depends on occupancy, member type, area, and local rules.
Why include load factors?
Load factors increase service loads for strength design checks. Common factors vary by code, method, and load combination.
Why separate dead load components?
Separate entries make assumptions clearer. They also help reviewers find heavy finishes, partitions, equipment, or service loads before design changes happen.