Convert Any Glass Panel to kg or lbs — in One Tap

Multiply the panel area by thickness and density. The standard formula: Weight (kg) = Area (m²) × Thickness (mm) × 2.5. The 2.5 is the density coefficient for float glass — meaning every square meter of glass at 1 mm thick weighs 2.5 kg. For imperial: Weight (lbs) = Area (ft²) × Thickness (in) × 12.8. Tempered glass is nearly the same density (2.52), so the difference is under 1% and usually negligible for planning.

At 1/4 inch (6 mm) thick, a square foot of glass weighs about 3.2 lbs. At 1/2 inch (12 mm), it doubles to about 6.4 lbs. The rule of thumb: every 1/8 inch of thickness adds roughly 1.6 lbs per square foot. In metric, every millimeter of thickness adds exactly 2.5 kg per square meter for standard float glass.

Multiply kg by 2.20462 to get lbs. For quick mental math, 1 kg ≈ 2.2 lbs. So a 40 kg panel is about 88 lbs, and a 100 kg order is about 220 lbs. The calculator above handles both units simultaneously — type in one system and see the other live.

Barely — tempered glass has a density of about 2.52 g/cm³ vs annealed's 2.50 g/cm³. That is a 0.8% difference. A 50 kg tempered panel would weigh about 0.4 kg more than the same annealed panel. For almost all practical purposes, you can use 2.5 for both and be within the rounding tolerance of supplier sheets.

Double glazed units (IGUs) are two panes of glass separated by an air or argon gap. The gas gap contributes essentially zero weight, so the unit's total weight is simply twice the single-pane weight. A 4/16/4 IGU (two 4 mm panes, 16 mm gap) weighs 2 × 10 kg/m² = 20 kg/m², plus the aluminum spacer bar which adds about 0.5 kg/m². Triple glazing is three panes, so roughly triple the single-pane weight.

6 mm float glass weighs 15 kg per m² (6 × 2.5 = 15). In imperial, that is about 3.07 lbs per square foot (0.236 in × 12.8 = 3.02 lbs/ft² — the small difference is rounding). This is the most common thickness for interior partitions and shower doors.

Laminated is two panes of glass bonded by a PVB interlayer. The interlayer adds about 0.1 kg per m² — almost nothing. The real difference is that laminated uses two glass panes: a 6+0.38+6 laminated unit has twice the glass mass of a single 6 mm pane. So a 6.38 mm laminated sheet weighs about 15.1 kg/m², while a single 6 mm sheet is 15 kg/m². The 6.38 mm number is nominal — the actual glass weight is from the two 6 mm panes.

Aquarium glass follows the same 2.5 kg/m²/mm rule. A 12 mm thick aquarium pane weighs 30 kg/m². A standard 120 × 50 × 50 cm aquarium with 12 mm glass needs five panels (front, back, two sides, bottom) totaling about 2.4 m² — the glass alone weighs roughly 72 kg. The water inside adds another 300 kg, so the full tank setup is over 370 kg. Always verify the floor load before placing a large aquarium.