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Electrical BOQ Estimator Calculator

Reference: Order-of-magnitude estimate

📋 ELECTRICAL

Free electrical BOQ estimator for early project budgeting. Get an order-of-magnitude bill of quantities and cost for cabling, DBs, lighting and power from built-up area, floors and connected load.

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📋 ASSUMPTIONS & BASIS

Order-of-magnitude estimate

Design criteria, governing codes and assumptions.

ℹ About This Calculator

At concept and feasibility stage you often need an electrical budget before any detailed design exists. This estimator produces an order-of-magnitude bill of quantities and cost from a handful of inputs — built-up area, number of floors, connected load and supply voltage — using typical per-square-metre and per-kW allowances for cabling, distribution boards, lighting, small power and the incoming supply, so you can frame a budget and compare options quickly.

These figures are order-of-magnitude only — real costs depend on specification, local rates, market conditions and the detailed design. The estimator is for early budgeting, option comparison and sanity-checking a quote, not for tendering. Always replace it with a measured BOQ from drawings and current supplier pricing before committing to a number.

Concept BOQ Method

Order-of-magnitude estimate

Step 1 - Apply per-m² allowances for lighting, small power and containment to the built-up area.
Step 2 - Add per-kW allowances for the main and sub-main distribution scaled to the connected load.
Step 3 - Add lump sums for the incoming supply, main panel and earthing based on load and voltage.
Step 4 - Sum the sections into a headline BOQ value and a per-m² rate for benchmarking.

Worked Example

For a 5,000 m² office over 5 floors with a 600 kW connected load, applying typical per-m² allowances for lighting, small power and containment plus per-kW main/sub-main and a supply lump sum yields a headline electrical budget and a per-m² benchmark rate — enough to seed the project cost plan before detailed design begins.

Using a Concept Electrical Estimate

What it is good for

Early budgets, feasibility studies and quick option comparisons — when you need a defensible number before there is anything to measure. It also helps benchmark a contractor rate against a typical per-m² figure.

What it is not

It is not a tender document. Specification, local labour and material rates, market conditions and the detailed layout all change the outcome, so the estimate carries a wide uncertainty band.

Refining the number

As the design develops, replace the allowances with measured quantities from the single-line diagram, cable schedules and layouts priced at current rates. The gap between the concept estimate and the measured BOQ is a useful measure of how the design has settled.

Frequently Asked Questions

How accurate is a concept electrical BOQ? +

It is an order-of-magnitude estimate, typically within a wide band of the final measured cost. Use it to frame a budget or compare options, not as a tender figure.

What drives electrical cost per square metre? +

The building use and specification — lighting density, small-power provision, containment, standby power and the incoming supply capacity all move the per-m² rate significantly.

Should I use connected load or demand load? +

Concept estimates usually start from connected load; a diversity factor is applied later when the demand load and supply capacity are firmed up in detailed design.

Does this replace a measured BOQ? +

No. A measured bill of quantities is taken off the drawings with current rates. This tool only gives an early ballpark before that work is done.

Can I use it to check a contractor quote? +

Yes, as a sanity check. A quote far outside the estimated band is worth questioning, but differences in scope and specification explain most of the gap.