• Rectangular V = (L × W) × H_fill
• Cube V = S × S × (S − clearance)
• Cylinder V = π × (D/2)² × H_fill
• Half cylinder V = ½·π·r²·H_fill (r = D/2, D is the flat-back chord)
• Corner (quarter) V = ¼·π·r²·H_fill
• Ellipse A = π·a·b (radii) → V = A × H_fill
• Hex/Oct (flat-to-flat F) A = (n/4)·F²·tan(π/n), n = 6 or 8 → V = A × H_fill
• L-shape A = L1·W1 + L2·W2 − min(L1, W2)·min(L2, W1) → V = A × H_fill
• Corner prism (right triangle) A = ½·a·b → V = A × H_fill

Substrate displacement = plan area × substrate depth.
Décor displacement = remaining volume × (decor % / 100). We clamp final volume ≥ 0.

1. Clear span S (front face):
   • Rectangular: S = L
   • Cube: S = S (side)
   • Hex (flat-to-flat F): S = F·tan(π/6)
   • Oct (flat-to-flat F): S = F·tan(π/8)
   • L-shape: S = max(L1, L2)
   • Right-triangle corner: S = √(A² + B²)
   • Cylinder / half / quarter-round / ellipse: curved front — not covered.
2. Base by height (annealed float) — pick the first band your H_fill exceeds:
   • ≤30 cm → 4 mm
   • 30–40 → 6 mm
   • 40–50 → 8 mm
   • 50–60 → 10 mm
   • 60–75 → 12 mm
   • 75–90 → 15 mm
   • >90 → 19 mm
3. Span tweak (unbraced):
   • S > 120 cm → +2 mm
   • S > 180 cm → another +2 mm (total +4 mm)
   • S < 60 cm → −1 mm (never below 4 mm)
4. Output range:
   • Annealed: t–(t+2) mm
   • Tempered: max(6, t−2)–t mm (tempered can’t be drilled; process spec matters)

Inputs are in centimeters or millimeters. 1,000 cm³ = 1 L. Water mass ≈ liters × 0.997 kg at ~20 °C (we display ≈1.0×). Bottom pressure p = ρ·g·H_fill (shown in kPa and psi).

• Top clearance — the gap you leave to stop slosh and keep fish in.
• Filled height (H_fill) — actual water height after that gap.
• Clear span — longest straight, unbraced run of glass on the front pane.

This app estimates volume and gives a conservative, rule-of-thumb thickness advisory for flat panes only. It does not perform strength/deflection checks and it does not design curved/bowed/laminated panels.

• DIN 32622 (DE) — Aquariums for domestic use (glass aquaria specification).
• ASTM E1300 (US) — Load-resistance tables/calculation for flat rectangular glass under uniform lateral loads; widely referenced by building codes.
• EN 16612 (EU) — Calculation method for load resistance of glass panes (supports laminated via effective-thickness methods).
• EN 16613 (EU) — Design of laminated glass; interlayer shear transfer depends on temperature and load duration (viscoelastic behavior).
• DIN 18008 (DE) — Glass in building; general design and partial-safety-factor rules for structural glass.
• EN 12150 — Toughened safety glass. Holes/notches/cutouts must be made before tempering; tempered panels are not cut/drilled post-process.

For curved/bowed/laminated tanks: a project-specific calculation to EN 16612/16613 (or an ASTM E1300-based method plus engineering judgement) is required. We only show “no auto thickness — consult a qualified builder/engineer”.

This calculator is for educational estimation only. It is not structural design or engineering advice, carries no warranty, and must not be used as the sole basis for fabrication or safety-critical decisions. Final glass specification, bracing and construction details must be determined and signed off by a competent builder or professional engineer to the applicable standard(s).