🧮 Cost of Farm Machinery Operation
Learn how fixed and variable costs are calculated for farm machinery, with a worked tractor-cultivator example.
Buying a machine is not the same as using it economically. A farmer, custom hiring centre, or extension worker must know how much a machine actually costs per hour and per hectare before deciding whether it is affordable and efficient.
Why Cost of Operation Is Calculated
Cost analysis helps us:
- estimate the economic usefulness of a machine
- compare different machines
- decide whether ownership or hiring is better
- fix custom hiring charges
- estimate payback from machinery investment
Total cost of operation is divided into:
- Fixed cost
- Variable or operating cost
Fixed Cost
Fixed cost is associated with machine ownership. It is incurred whether or not the machine is actually used.
Important fixed-cost components are:
- depreciation
- interest on investment
- taxes
- insurance
- housing
Depreciation
Depreciation is the reduction in machine value with time. In many farm machines, obsolescence is a major cause of depreciation, because better designs or changed farm practices may make an old machine less useful even before it is fully worn out.
Using the straight-line method:
D = (C - S) / (L x H)
Where:
- D = depreciation cost in Rs/hr
- C = initial cost of machine
- S = salvage value
- L = life of machine in years
- H = annual working hours
Usually, salvage value is taken as about 10 percent of initial cost.
Interest on Investment
Money used to buy a machine could have been invested elsewhere. Therefore, interest on investment is treated as a real cost.
First calculate the average purchase price:
A = (C + S) / 2
Then:
I = (A x i) / (100 x H)
Where:
- I = interest cost in Rs/hr
- A = average purchase price
- i = interest rate
- H = annual working hours
In many worked examples, interest is assumed as 14 percent.
Taxes, Insurance, and Housing
If exact values are not available, these are often estimated together.
Combined annual charges can be taken as about 3 percent of average purchase price, including:
- taxes
- insurance
- housing or shelter cost
Formula:
T, I and H = (3 x A) / (100 x H)
Total fixed cost is:
Fixed cost = Depreciation + Interest + Taxes/Insurance/Housing
Variable Cost
Variable cost is incurred only when the machine is used. It depends directly on operation.
Major components are:
- repair and maintenance
- fuel
- lubricating oil
- labour or operator charges
Repair and Maintenance Cost
Repair and maintenance keep the machine in working condition and cover wear, part failure, tyre replacement, and routine service.
In many practical calculations, repair and maintenance are taken as 10 percent of initial machine cost per year:
R&M = (10 x C) / (100 x H)
Where:
- R&M = repair and maintenance cost in Rs/hr
- C = initial cost
- H = annual use in hours
Fuel, Oil, and Labour Cost
Fuel cost
Fuel cost = fuel consumed per hour x fuel price per litre
Lubricating oil cost
For simple calculations, lubricating oil cost is often taken as 30 percent of fuel cost.
Operator cost
Operator cost = (number of persons x daily wage) / 8
This formula assumes an 8-hour working day.
Total variable cost is:
Variable cost = R&M + fuel cost + oil cost + operator cost
Total Cost of Operation
Total machinery cost per hour:
Total cost per hour = Fixed cost + Variable cost
If field capacity is known, then:
Cost per hectare = Cost per hour / Field capacity (ha/hr)
This is the most useful value when comparing alternative machines in field conditions.
Worked Example: Tractor and Cultivator
Problem data
A farmer owns:
- a 35 hp Massey Ferguson tractor costing Rs. 3,00,000
- an 11-tined cultivator costing Rs. 12,000
Given:
- tractor life = 10 years
- tractor annual use = 1000 hours
- cultivator life = 10 years
- cultivator annual use = 400 hours
- cultivator tine spacing = 20 cm
- field speed = 4 km/hr
- diesel consumption = 3 litres/hr
The task is to calculate the cost of ploughing 2 ha of land with the cultivator, assuming usual values for other required data.
Step 1: Tractor Fixed Cost
Depreciation
- C = 3,00,000
- S = 30,000 (10 percent of C)
- L = 10
- H = 1000
D = (3,00,000 - 30,000) / (10 x 1000) = Rs. 27/hr
Interest
A = (3,00,000 + 30,000) / 2 = Rs. 1,65,000
I = (1,65,000 x 14) / (100 x 1000) = Rs. 23.1/hr
Taxes, insurance, housing
T, I and H = (3 x 1,65,000) / (100 x 1000) = Rs. 4.95/hr
Total fixed cost of tractor
27 + 23.1 + 4.95 = Rs. 55.05/hr
Step 2: Tractor Variable Cost
Repair and maintenance
R&M = (10 x 3,00,000) / (100 x 1000) = Rs. 30/hr
Fuel cost
3 litres/hr x Rs. 45/litre = Rs. 135/hr
Lubricating oil cost
30 percent of 135 = Rs. 40.5/hr
Operator cost
(1 x 240) / 8 = Rs. 30/hr
Total variable cost of tractor
30 + 135 + 40.5 + 30 = Rs. 235.5/hr
For exam-oriented rounding, this is often shown as about Rs. 235/hr.
Total tractor operating cost
55.05 + 235.5 = Rs. 290.55/hr
Many notes round this near Rs. 290.05 to Rs. 290.55 per hour depending on rounding method.
Step 3: Cultivator Fixed Cost
Depreciation
- C = 12,000
- S = 1,200
- L = 10
- H = 400
D = (12,000 - 1,200) / (10 x 400) = Rs. 2.7/hr
Interest
A = (12,000 + 1,200) / 2 = Rs. 6,600
I = (6,600 x 14) / (100 x 400) = Rs. 2.31/hr
Taxes, insurance, housing
T, I and H = (3 x 6,600) / (100 x 400) = Rs. 0.495/hr
Total fixed cost of cultivator
2.7 + 2.31 + 0.495 = Rs. 5.51/hr
Step 4: Cultivator Variable Cost
Repair and maintenance
R&M = (10 x 12,000) / (100 x 400) = Rs. 3/hr
For a passive implement:
- lubricating oil cost = nil
- operator cost = nil
- fuel cost is already counted with tractor
Total cultivator variable cost
Rs. 3/hr
Total cultivator operating cost
5.51 + 3 = Rs. 8.51/hr
Step 5: Combined Cost of Tractor and Cultivator
Tractor cost + implement cost = 290.05 or 290.55 + 8.51
So combined operating cost is approximately:
Rs. 298.55 to Rs. 299.06/hr
The exact answer may vary slightly due to rounding.
How This Is Used in Practice
Once hourly cost is known, a farmer can:
- estimate the cost of completing 2 ha
- compare custom hiring with ownership
- compare different implements
- judge whether better field capacity can reduce per-hectare cost
Example: if field capacity increases because of better speed or width, the cost per hectare falls even when cost per hour remains similar.
Summary Cheat Sheet
- Machine operating cost has two parts: fixed cost and variable cost.
- Fixed cost includes depreciation, interest, taxes, insurance, and housing.
- Variable cost includes repair, fuel, lubricating oil, and labour.
- Straight-line depreciation formula: D = (C - S) / (L x H).
- Average purchase price: A = (C + S) / 2.
- Interest formula: I = (A x i) / (100 x H).
- Taxes, insurance, and housing are often taken together as 3 percent of average cost per year.
- Repair and maintenance are often taken as 10 percent of initial cost per year.
- Oil cost is often estimated as 30 percent of fuel cost.
- Cost per hectare is obtained by dividing cost per hour by field capacity.
References
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