Estimation and Costing
Estimation and Costing tests measurement, rate analysis and preparation of a bill of quantities. The exam expects correct units, wastage, labour and overhead, not just a pipe length.
Core method
- Measure in a measurement book (MB) with description, number, length, breadth and height.
- Use standard units: metre for pipe, number for fittings, square metre for painting, cubic metre for excavation.
- Rate analysis = material + labour + plant + overhead + profit; add GST as applicable.
- Add wastage: commonly 5% for pipe and 2–5% for fittings, depending on the item.
- Include lead and lift for material transport and vertical raising.
Worked example
A BOQ needs 60 m of 15 mm CPVC pipe. Add 5% wastage: 60 × 1.05 = 63 m. If the rate is ₹120/m, material cost = 63 × 120 = ₹7,560. Add fittings, labour and overhead separately; do not bury them in the pipe rate unless the item is composite.
Traps
Mixing metres and numbers, forgetting elbows and tees, or omitting wastage and labour costs marks. A low bid that ignores working capital and transport is a commercial error, not a competitive advantage. Check the scheduled rate and specification before pricing a substitute.