Introduction
Earthwork includes excavation (cutting) and filling (embankment). It is measured in cubic metres as per IS 1200 and forms a major part of foundation and road estimates.
This guide covers:
- Simple excavation (foundations, trenches)
- Trapezoidal and prismoidal formulae for linear earthwork
- Bulking and compaction factors
Units (IS 1200)
| Item | Unit | Payment |
|---|---|---|
| Earthwork in excavation | cum | per cum |
| Earthwork in filling (foundation trenches) | cum | per cum |
| Earthwork in filling (plinth) | cum | per cum |
Simple Excavation (Buildings)
For foundation trenches, use:
Volume = Length × Breadth × Depth
- Length, breadth – At bottom of excavation (or average of top and bottom)
- Depth – From ground level to bottom of excavation
For stepped excavation, find volume of each step and add.
Example: Foundation Trench
Single room, centre line 19.2 m, trench width 0.9 m, depth 1.4 m.
Volume = 19.2 × 0.9 × 1.4 = 24.192 cum
See quantity takeoff methods for long wall–short wall and centre line approaches.
Trapezoidal Formula (Mean Area Method)
For roads, canals, or any linear work with cross-sections at regular intervals:
V = (D/2) × (A₁ + 2A₂ + 2A₃ + ... + 2Aₙ₋₁ + Aₙ)
Where:
- A₁, A₂, ... Aₙ = areas of consecutive cross-sections (sq m)
- D = distance between sections (m)
- n = number of sections
Simplified (Two Sections)
V = (D/2) × (A₁ + A₂)
Example
| Chainage | Area (sq m) |
|---|---|
| 0 | 20 |
| 10 m | 25 |
| 20 m | 18 |
| 30 m | 22 |
D = 10 m
V = (10/2) × (20 + 2×25 + 2×18 + 22) = 5 × 128 = 640 cum
Prismoidal Formula
More accurate when cross-sections change. Use when number of sections is odd (3, 5, 7...):
V = (D/6) × (A₁ + Aₙ + 4×(A₂ + A₄ + A₆ + ...) + 2×(A₃ + A₅ + A₇ + ...))
Odd subscript: multiply by 4
Even (middle): multiply by 2
Example (5 sections)
A₁=20, A₂=25, A₃=18, A₄=22, A₅=19, D=10 m
V = (10/6) × (20 + 19 + 4×(25+22) + 2×18)
= (10/6) × (39 + 188 + 36) = (10/6) × 263 ≈ 438 cum
Bulking and Compaction
Bulking
Excavated soil occupies more volume than in-situ:
- Sand: ~10–15%
- Ordinary soil: ~15–25%
- Clay: ~20–30%
Bulking factor = Volume after excavation / Volume in-situ
e.g., 1.2 means 20% bulking.
Compaction
Fill is compacted to required density. Compaction factor = In-situ volume / Compacted volume
Often 0.9–0.95 (i.e., 1 cum fill needs 1.05–1.1 cum loose soil).
Application
- Excavation to fill:
Fill volume (compacted) × (1 + bulking) ≈ Excavation required - Borrow pit:
Order more excavated material than fill volume if transporting from elsewhere.
Volume from Spot Levels
For irregular terrain (e.g., building site):
- Take grid of spot levels.
- Find cut/fill at each grid point (depth below/above formation).
- Use formula:
V = (A/4) × (Σ h at corners)
Where A = area of one grid cell, h = cut/fill depth.
For prismoid over each cell: V = (A/4) × (h₁ + h₂ + h₃ + h₄).
Side Slopes
For trapezoidal cross-section (road in cutting/filling):
Area = (B + s×h) × h
(approximate for uniform slope)
Where:
- B = bottom width
- h = depth of cut or fill
- s = horizontal distance per 1 m vertical (e.g., 1.5:1 → s = 1.5)
Measurement Rules
-
Linear – to nearest 0.01 m
-
Area – to nearest 0.01 sq m
-
Volume – to nearest 0.01 cum
-
Same work, different conditions – measure separately (e.g., soft soil vs hard rock excavation).
Cost of Earthwork in India (2025-26 Rates)
Earthwork rates vary dramatically based on soil type, depth, and city. Here are typical rates per cubic metre:
| Type of Earthwork | Rate per m³ (₹) | Measurement Ref |
|---|---|---|
| Ordinary soil excavation (0-1.5m depth) | ₹150-250 | IS 1200 Part 1 |
| Ordinary soil (1.5-3.0m depth) | ₹200-350 | IS 1200 Part 1 |
| Hard soil / murrum excavation | ₹300-500 | IS 1200 Part 1 |
| Soft rock (weathered) | ₹600-1,000 | Separate item |
| Hard rock blasting | ₹1,200-2,500 | Separate item |
| Filling with excavated earth (within 50m lead) | ₹100-180 | IS 1200 Part 1 |
| Filling with borrowed earth (including transport) | ₹250-500 | Lead charges extra |
| Sand filling (in foundation/plinth) | ₹1,800-3,500 | Based on sand rate |
| De-watering (per hour) | ₹300-600 | Pump + operator |
Worked Example: Foundation Excavation Cost
For a residential building, 10m × 10m plan, strip foundation 1.2m deep × 0.9m wide:
- Perimeter trench: (10+10+10+10) × 1.2 × 0.9 = 43.2 m³ of ordinary soil excavation
- At ₹200/m³: Excavation cost = ₹8,640
- Refilling: ~60% of excavated soil used for backfilling = 25.9 m³ × ₹120/m³ = ₹3,108
- Disposal of surplus: 17.3 m³ × ₹180/m³ (including lead) = ₹3,114
- Total earthwork cost: ~₹14,862
Machine vs Manual Excavation
| Parameter | Manual | JCB/Excavator |
|---|---|---|
| Rate | ₹150-300/m³ | ₹80-150/m³ |
| Speed | 2-3 m³ per worker per day | 80-120 m³ per day |
| Best for | Small trenches, tight spaces | Open foundations, large sites |
| Typical machine hire | — | ₹1,500-2,500/hour (JCB) |
For small residential projects, manual excavation is common. For anything above 50 m³, machine excavation is more economical.
IS Code References for Earthwork
- IS 1200 Part 1:1992 — Method of measurement of building works: Earthwork
- IS 2720 (various parts) — Methods of test for soils (moisture, density, bearing capacity)
- IS 3764:1992 — Excavation work: Code of safety
- IS 6403:1981 — Code of practice for determination of bearing capacity of shallow foundations
Next Steps
- Quantity Takeoff Methods – Long wall, short wall, centre line for building foundations
- Detailed Estimates – Full estimate including earthwork
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Senior Construction Consultant at Yojo
10+ years of experience
Reviewed on 18 May 2026
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