# Lintel Quantity Calculator

Enter opening width, quantity and wall thickness to get lintel length, concrete volume, formwork and a suggested depth.

- Page: https://jianzhujisuan.com/en/lintel-schedule
- Category: Masonry (https://jianzhujisuan.com/en/c/masonry)
- Chinese version: https://jianzhujisuan.com/zh/lintel-schedule.md
- Data checked: 2026-10-25

## Quick result

With the default inputs (Opening width 1.2 m, Number of openings 10 pcs, Wall thickness 0.24 m, Lintel depth 0.15 m, Bearing length each end 0.25 m): **Total lintel length 17.0 m**

## Inputs

| Parameter | Type | Default | Unit | Note |
|---|---|---|---|---|
| Opening width | number | 1.2 | m | Clear width of the opening |
| Number of openings | number | 10 | pcs |  |
| Wall thickness | number | 0.24 | m |  |
| Lintel depth | number | 0.15 | m | Enter 0 to auto-use opening / 8 |
| Bearing length each end | number | 0.25 | m | Usually 250 mm; 300-370 mm for openings over 1.5 m |

## Formula

- **Length per lintel**: L = opening width + 2 × bearing
- **Suggested depth**: h = opening ÷ 8 (round up to 50 mm, min 120 mm)
- **Concrete**: V = L × wall thickness × h × quantity
- **Formwork**: A = (2 × L × h + L × wall thickness) × quantity

## Worked example

10 openings 1.2 m wide, 240 mm wall, 250 mm bearing, depth left at 0: depth auto 0.15 m, 1.70 m per lintel, 17 m total, 0.612 m³ concrete, 9.18 m² formwork.

## Questions

### Why must a lintel bear into the wall, and how far?

The lintel must transfer load into the masonry either side, not merely span the gap. 250 mm per end is standard; 300-370 mm for openings over 1.5 m; more in seismic zones or where the wall end is close to the opening. Too short a bearing crushes the wall end — a very common defect.

### Precast or cast-in-situ lintels?

Precast is fast, formwork-free and consistent — ideal for standard openings in volume, chosen straight from the album. Cast-in-situ gives better integrity and handles non-standard sizes, heavy loads or monolithic casting with ring beams, at the cost of formwork and curing time.

### Must the depth always be opening / 8?

1/8 is a starting rule of thumb; the code requirement is a real bending and shear check against the actual wall load above. Large openings, tall walls above, or concentrated loads (padstones, canopies) must be checked rather than proportioned. Seismic zones add minimum reinforcement ratios and stirrup densifying.

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Generated by BuildCalc. All calculations run in your browser; no data is uploaded. Formulas follow national standards and common trade practice; local codes govern.