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Microlesson · 5-min read

Machine Hour Rate — Computation

# Machine Hour Rate (MHR)

MHR = Hourly rate of running a machine — i.e., total cost of running the machine ÷ total hours the machine was used.

$$\text{Machine Hour Rate} = \frac{\text{Total Cost of running the machine}}{\text{Effective Machine Hours}}$$

It is the most accurate absorption method for machine-intensive production.

## Two Types of Cost

### A. Fixed / Standing Charges (do not vary with hours used)

These exist whether the machine runs or not.

ItemNotes
Depreciation not related to activityTime-based depreciation
Rent of machineFixed lease/space
Insurance of machineAnnual premium
Wages of workers and Bonus (for the machine)Even if idle, paid
General Overheads of DepartmentAllotted share
Total Fixed ChargesXXX

### B. Running Charges (vary with hours machine is actually run)

ItemNotes
Repairs and MaintenanceWear-and-tear based
PowerDirect usage cost
Depreciation related to activityUsage-based depreciation
LubricantsPer running hour
Sundry Variable ExpensesVarious small costs
Total Running ChargesXXX

## ⚠️ Important — Calculating the Hours

### Hours Paid to Workers

```

Hours Paid = Normal Hours − Absent Without Pay

```

(Absence with pay is still paid for — so it remains in 'hours paid'.)

### Effective Machine Hours (used in denominator)

```

Effective Machine Hours = Normal Hours

− Absent Without Pay

− Absent With Pay

− Idle Time

(= actual hours the machine was running)

```

> Take special care of:

> - Number of machines (multiply by no. of machines)

> - Number of months (annual figures need to be allocated)

## Comprehensive vs. Ordinary Machine Hour Rate

  • Ordinary MHR = (Running charges only) ÷ Machine Hours.
  • Comprehensive MHR = (Fixed + Running) ÷ Machine Hours, including operator wages.

Worked example

### Example 1

Example — Computing Effective Machine Hours:

A worker is provided 2,000 normal hours in a year.

  • Absent without pay = 100 hrs
  • Absent with pay (leave) = 50 hrs
  • Idle time (set-ups, breakdowns) = 80 hrs

Hours paid to worker = 2,000 − 100 = 1,900 hrs

Effective Machine Hours = 2,000 − 100 − 50 − 80 = 1,770 hrs

### Example 2

Example — Machine Hour Rate computation:

Fixed/Standing charges p.a.:

  • Depreciation (time-based) ₹60,000
  • Rent of machine ₹24,000
  • Insurance ₹6,000
  • Operator wages (with bonus) ₹1,20,000
  • General OH of dept ₹30,000
  • Total Fixed = ₹2,40,000

Running charges (assumed at 1,770 effective machine hours):

  • Power ₹70,800
  • Repairs ₹17,700
  • Lubricants ₹8,850
  • Activity-based depreciation ₹26,550
  • Total Running = ₹1,23,900

Total Cost = 2,40,000 + 1,23,900 = ₹3,63,900

Machine Hour Rate = 3,63,900 / 1,770 = ₹205.59 per machine hour.

⚠️ Common exam mistakes

  • Including absent with pay hours in effective machine hours — wrong, machine wasn't running.
  • Mixing up hours paid (for wages) and effective machine hours (for MHR denominator).
  • Forgetting to scale up by number of machines or full-year basis when given monthly data.
  • Treating activity-based depreciation as fixed — it varies with usage, so it goes into Running Charges.
  • Failing to add operator wages and bonus for a Comprehensive MHR.
Reference:
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