Three main estimate types are used at different project stages:
1. Preliminary Estimate (Rough Cost Estimate)
- Prepared at initial planning stage with limited information
- Accuracy: ±20-30% of actual cost
- Based on historical data and unit costs
- Used for feasibility studies and budget approval
- Method: Area × Rate per unit
📌 Quick Example:
Building size: 1000 m²
Rate: ₹1500/m² (for residential)
Preliminary Estimate = 1000 × 1500 = ₹15,00,000
2. Detailed Estimate
- Prepared after complete design drawings available
- Accuracy: ±5-10%
- Item-by-item detailed costing
- Used for tender documents and authorization
- Includes all material, labour, equipment, overhead
3. Revised Estimate
- Updated during project execution
- Reasons: Design changes, scope additions, price changes
- Accuracy: ±5-10%
- Based on actual conditions and variations
Estimate Selection Flow:
Project Initiation → Preliminary Estimate (Feasibility)
↓
Design Completion → Detailed Estimate (Tender)
↓
During Execution → Revised Estimate (If needed)
