Masonry & Brickwork
Lintel Bearing Length Calculator
Calculates minimum lintel bearing length by span and wall type
Updated 26 June 2026 · Live
What this tool does
Calculates minimum lintel bearing length by span and wall type.
Lintel Bearing Length Calculator — enter the opening width ({opening_width_m}) to estimate the minimum lintel length ({result}) based on standard bearing allowances.
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Formula Used
How the lintel bearing length calculator works
Calculates minimum lintel bearing length by span and wall type. The calculator takes your dimensions and supplier rates, applies a standard Australian trade formula, and returns a quantity with an indicative cost. Every figure is an estimate — site conditions always move the final number.
Typical Australian masonry and brickwork wastage
Typical Australian brickwork wastage is 5%, rising to 10% for Flemish bond or similar decorative patterns. Blockwork at 5–7% is adequate for straightforward walling. Our defaults reflect common Australian trade allowances, and can be adjusted upwards for non-standard geometry or downwards where experience supports a lower figure.
What this tool does not do
It does not replace a professional quote, factor regional pricing, assess structural adequacy, or confirm National Construction Code (NCC) compliance. Those remain the responsibility of a suitably qualified designer, surveyor, or your building surveyor.
On-site considerations for lintel bearing length
Wet weather delays mortar curing and can wash out joints — protect fresh work with hessian or plastic. Below 3°C, fresh mortar or concrete needs an accelerator or a winter mix to cure reliably.
the National Construction Code (NCC) and compliance
Loadbearing masonry is covered by the National Construction Code and AS 3700. Cavity wall ties, DPC, and cavity trays are all the NCC items, not optional. When in doubt, a pre-application enquiry to the local council can give early clarity, which tends to be less costly than retrospective correction.
Before you order
Order bricks by the pack and keep them dry on pallets. Wet bricks will leach salts to the face and leave permanent staining. Cross-checking the calculator’s output against a supplier quote helps catch differences in pricing assumptions — ask for exact product specifications (grade, finish, batch number) and confirm delivery timescales against your programme.
Adjusting the defaults
Every input in this calculator is editable. Enter your own dimensions, supplier prices, and wastage allowance — the output recalculates instantly. If the defaults feel off for your region or project type, your own numbers always override them.
Using this lintel bearing length calculator alongside other BuildMetricLab tools
This calculator works best as part of a planning workflow. Pair the quantity with our project contingency, labour-hours, and material-cost calculators to build a complete estimate before you pick up the phone to a supplier. All BuildMetricLab tools run entirely in your browser — no sign-up, no data sent anywhere, and every formula is shown on-page so you can audit the maths.
Sources & methodology
Calculates minimum lintel bearing length by span and wall type. Every result is calculated from the values you enter, and all inputs are editable.
Frequently asked questions
Are lintel bearing length calculator results accurate enough to order materials?
Use them as a starting estimate only. Verifying the final quantity with your supplier or contractor before ordering is good practice — site conditions, wastage and cut-offs all affect the true figure.
How is the bearing allowance determined?
The calculator applies a standard minimum bearing length at each end of the opening, which increases in tiers as the opening width increases (matching typical masonry lintel guidance). Manufacturer span tables or an engineer may specify a longer bearing for heavier loads — always confirm before ordering.
Do I still need a qualified professional to confirm the lintel size?
Yes. This tool is a planning estimator only. For works that affect structure, the National Construction Code (NCC), or similar regulated areas, consult a suitably qualified professional such as a structural engineer before finalising the lintel size or ordering materials.
What if my opening width is right at a threshold (e.g. 1.2 m or 3.0 m)?
The bearing allowance increases in steps at 1.2 m and 3.0 m opening widths. If your measured width is close to a threshold, measure carefully and consider using the higher bearing allowance, or confirm the exact requirement with the lintel manufacturer's span tables.
Spotted something off?
Calculations or display — let us know.
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