Inputs
Pick the fire feature footprint.
Total inside length.
Total inside width.
Inside diameter of the circular pan.
Annulus between inner void and outer edge.
Typical depth is 1.5–3 inches depending on glass size.
Percent volume removed by burners, trays, spacers.
Handling, settling, and trimming allowance.
Typical bulk density for fire glass ranges widely; adjust if known.
Common retail bag sizes are 10 lb or 20 lb.
All calculations are estimates.
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Results
Area
0.00 ft²
Volume
0.000 ft³
Weight
0.0 lb
Bags
0 bags
Coverage at 1" depth (weight)
0.0 lb/ft²
Notes: Results include loss/wastage and hardware displacement adjustments as entered.
Example Data
| Project | Shape | Key Dimensions | Depth | Density | Bags (10 lb) |
|---|---|---|---|---|---|
| Patio linear table | Rectangle | 48 in × 12 in | 2 in | 85 lb/ft³ | ~8 |
| Round fire pit | Circle | Ø 30 in | 2 in | 85 lb/ft³ | ~9 |
| Ring around burner | Annular | OD 36 in, ID 12 in | 2.5 in | 85 lb/ft³ | ~12 |
Formula Used
- Area (ft²): Rectangle: L × W; Circle: π × (D/2)²; Ring: π × (OD² − ID²)/4.
- Depth (ft): depth_in / 12.
- Raw Volume (ft³): Area × Depth.
- Displacement Adjusted Volume (ft³): Raw × (1 − Displacement%).
- Loss/Wastage Adjusted Volume (ft³): Above × (1 + Waste%).
- Weight (lb): Adjusted Volume × Bulk Density.
- Bags: ceil(Weight / Bag Size).
- Coverage at 1" depth (lb/ft²): Bulk Density × (1/12).
Bulk density depends on glass size and manufacturer; consult product data when available.
How to Use
- Select the shape matching your fire feature footprint.
- Enter inside dimensions and desired glass bed depth.
- Adjust displacement for burners, trays, spacers if they occupy volume.
- Set loss/wastage to cover trimming, breakage, or future top‑offs.
- Specify bulk density and bag size from your supplier’s specs.
- Click Calculate to see volume, weight, and bags.
- Use Download CSV or Download PDF to export.
- Copy the shareable link to revisit with inputs prefilled.
FAQs
1) What bulk density should I use?
Densities vary by brand and chip size. If unknown, start at 85 lb/ft³ and compare against vendor guidance.
2) How deep should the glass bed be?
Common depths are 1.5–3 inches. Deeper beds require more glass but can improve coverage.
3) Why include displacement?
Burner rings, pans, and supports take space. Subtracting their volume avoids over‑ordering.
4) How accurate are bag counts?
They depend on actual density and your bag size. Add a small allowance for top‑up and breakage.
5) Can I switch units?
Click the unit buttons to toggle inches/feet. Values convert automatically to keep calculations consistent.