Granite Worktop Weight Calculator
Instantly estimate the mass and load requirements for your kitchen renovation project. Accurate calculations for transport and installation safety.
Enter total length in millimeters (mm).
Please enter a valid positive length.
Standard depth is often 600mm. Enter in mm.
Please enter a valid positive width.
20mm (Standard)
30mm (Heavy Duty)
40mm (Double)
Custom Thickness
Select the thickness of your granite slab.
Standard Granite (2600 kg/m³)
Black Galaxy / High Density (2900 kg/m³)
Quartz / Engineered Stone (2400 kg/m³)
Marble (2700 kg/m³)
Density varies by stone type. Standard granite is approx 2600-2700 kg/m³.
We subtract approx 12kg per standard cutout to adjust net weight.
Cannot be negative.
Estimated Total Weight
0 kg
Total Area
0 m²
Weight per Meter
0 kg/m
Load (lbs)
0 lbs
Formula Used: Weight (kg) = (Length × Width × Thickness × Density) – (Cutout Weight)
Weight Comparison
How this slab compares to other common materials of the same size.
Specification Summary
| Parameter | Value |
|---|
What is a Granite Worktop Weight Calculator?
A granite worktop weight calculator is an essential planning tool for homeowners, kitchen fitters, and construction professionals. It determines the total mass of natural stone slabs based on dimensions and density. Because granite is significantly denser than laminate or wood, accurate weight calculation is critical for ensuring cabinetry can support the load, planning safe manual handling, and arranging appropriate transport logistics.
Using a calculator helps prevent structural failures and workplace injuries by providing precise figures before the stone arrives on site. Whether you are installing a small vanity unit or a massive kitchen island, knowing the specific weight is the first step in a successful renovation.
Granite Worktop Weight Calculator Formula
The calculation relies on the physics of volume and density. The primary formula used to determine the mass of a granite slab is:
Mass (kg) = Volume (m³) × Density (kg/m³)
To break this down for a standard kitchen worktop, we first convert all dimensions to meters:
- Step 1: Convert Length, Width, and Thickness to meters.
- Step 2: Multiply L × W × T to get Volume in cubic meters.
- Step 3: Multiply Volume by the Density of the specific stone.
- Step 4: Subtract estimated weight for cutouts (sinks, hobs).
Variables Table
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| L | Length of the worktop | mm (converted to m) | 1000mm – 3200mm |
| W | Width (Depth) | mm (converted to m) | 600mm – 1200mm |
| T | Thickness | mm (converted to m) | 20mm or 30mm |
| ρ (Rho) | Density | kg/m³ | 2600 – 2900 kg/m³ |
Practical Examples
Example 1: Standard Kitchen Run
A homeowner is installing a standard straight run of granite worktop against a wall.
- Dimensions: 3000mm (L) x 600mm (W) x 30mm (T).
- Material: Standard Granite (Density approx 2600 kg/m³).
- Calculation: 3.0m x 0.6m x 0.03m = 0.054 m³.
- Weight: 0.054 m³ x 2600 kg/m³ = 140.4 kg.
Financial & Safety Implication: A 140kg load requires at least 3-4 people to lift safely or mechanical aid. Standard kitchen base units are generally rated to support this, provided legs are adjusted correctly.
Example 2: Large Kitchen Island
A luxury kitchen island featuring dense Black Galaxy granite.
- Dimensions: 2500mm (L) x 1200mm (W) x 30mm (T).
- Material: Black Galaxy (Density approx 2900 kg/m³).
- Calculation: 2.5m x 1.2m x 0.03m = 0.09 m³.
- Weight: 0.09 m³ x 2900 kg/m³ = 261 kg.
Financial & Safety Implication: This exceeds the safe lifting limit for manual handling. Professional stone lifters or a gantry crane may be required, increasing installation costs. Floor joists may need reinforcement.
How to Use This Granite Worktop Weight Calculator
- Measure Length: Enter the total length of the slab in millimeters.
- Measure Width: Enter the depth (front to back) in millimeters. Standard depth is 600mm.
- Select Thickness: Choose between 20mm (common for splashbacks or modern looks) or 30mm (standard for strength).
- Choose Stone Type: Select the density. If unsure, "Standard Granite" is a safe baseline.
- Account for Cutouts: Enter the number of sinks or hobs. The calculator will subtract weight accordingly.
- Review Results: Use the "Total Weight" to plan your lifting crew and transport vehicle.
Key Factors That Affect Granite Weight
Understanding what drives the weight of your installation helps in budgeting and safety planning.
1. Slab Thickness (20mm vs 30mm)
This is the most direct multiplier. A 30mm slab is 50% heavier than a 20mm slab. While 30mm offers greater structural rigidity for overhangs (like breakfast bars), the extra weight increases shipping costs and installation difficulty.
2. Stone Density
Not all "granite" is equal. True geological granite sits around 2600-2700 kg/m³. However, dense black stones (often gabbro or basalt geologically) can reach 3000 kg/m³. A 10% increase in density means 10% more weight to lift.
3. Cutouts and Waste
While the gross slab is heavy, cutting out a hole for a sink or induction hob removes material. A typical sink cutout might remove 10-15kg of stone. This reduces the static load on the cabinet but makes the slab more fragile during transport.
4. Reinforcements
Some granite slabs, especially fragile exotic varieties, contain rodding (steel or fiberglass rods glued into the underside). While these add minimal weight, they are crucial for preventing cracks under the stone's own weight.
5. Water Absorption
Granite is porous. If stored outside in rain, a slab can absorb a small amount of water, temporarily increasing its weight. Always allow stone to dry before sealing and final installation.
6. Edge Profile
While the profile (bullnose, ogee) doesn't add weight, a "mitred drop edge" creates the illusion of a thicker slab (e.g., 50mm) using a 20mm slab. This keeps weight down while achieving a substantial aesthetic.
Frequently Asked Questions (FAQ)
How heavy is a square meter of granite?
A 30mm thick slab of standard granite weighs approximately 81 kg per square meter. A 20mm slab weighs approximately 54 kg per square meter.
Can IKEA cabinets support granite worktops?
Yes, most modern kitchen cabinets (including IKEA) are designed to support the weight of stone worktops, provided the legs are correctly spaced and adjusted. However, for very large islands, additional support frames are recommended.
Do I need a structural engineer for granite worktops?
For standard kitchen runs on a ground floor, usually no. However, if installing a large island (250kg+) on an upper floor with wooden joists, you should consult an engineer to ensure the floor can handle the dead load.
Is Quartz heavier than Granite?
They are very similar, but Quartz is often slightly less dense (approx 2400 kg/m³) compared to Granite (2600-2700 kg/m³), making it marginally lighter for the same dimensions.
How many people are needed to lift a granite slab?
As a rule of thumb, one person is needed for every 20-25kg of weight for safe lifting. A 100kg island piece requires at least 4 people or mechanical suction lifters.
Does the color of granite affect its weight?
Yes, generally darker stones (like Absolute Black) are denser and heavier than lighter colored stones (like Kashmir White) due to their mineral composition.
What is the specific gravity of granite?
The specific gravity of granite typically ranges from 2.6 to 2.8, meaning it is 2.6 to 2.8 times heavier than an equal volume of water.
How accurate is this calculator?
This calculator provides a high-confidence estimate (+/- 5%). However, natural stone varies. Always allow a safety margin when designing structural supports.