Financial calculations
The original nine calculators retain their positive-input arithmetic. They cover labour burden, job profit, overhead, equipment, hourly break-even, margin and markup, change orders, retention and bid capacity. Undefined ratios with zero denominators are marked unavailable in the interface. Automated worked-example checks are software validation, not an independent professional audit.
Quantity models and units
Physical models use metres, square metres, cubic metres and litres internally, with explicit length, area, volume and liquid conversion factors. For example, one foot is 0.3048 metre and one US gallon is 3.785411784 litres. Imperial and US gallons are distinct. Conversion tests check round trips and dimensional compatibility. Presets are editable sample dimensions, not product standards or structural specifications.
Costs, rounding and tax
Physical-tool unit prices start at zero so the user supplies a quote. Waste is applied to quantity before whole-item or whole-pack rounding. Labour and equipment are entered as separate allowances. Contingency applies to materials plus those allowances; tax applies to the resulting subtotal including contingency. This tax base is a modelling assumption, not a claim about local law. Monetary outputs are displayed to two decimal places; calculations retain more precision.
Sources and editorial review
Product dimensions and coverage should come from the chosen manufacturer and supplier quote. Tax rates and eligibility should come from the applicable authority or your adviser. This site does not invent pricing databases, reviewer biographies, certification or compliance claims. Content review dates describe an editorial update, not a live price check. Contact Numbriv to report a reproducible error.
Regional material examples
- Timber and board stock may be sold in imperial sizes alongside metric drawings.
- Example gypsum sheet: 4 × 8 ft; do not round its area to 1.2 × 2.4 m.
- Reinforcing bar designations such as 10M are not inch dimensions; confirm the specification.
These are examples, not standards. Use the actual product dimensions and project specification.
Public references
Questions or corrections?
Published by Numbriv. Questions, corrections and privacy requests: info@numbriv.com.
Privacy · Terms