Methods of Depreciation (Edexcel IGCSE Accounting): Revision Note
Exam code: 4AC1
Straight line depreciation
What is the straight line method of depreciation?
- The straight line method of depreciation assumes that a non-current asset loses value at a constant rate over its useful life - This means that the expense for its depreciation is the same each year 
- The carrying value can reach $0 - This is when the asset is fully depreciated 
 
 
- You could be given the depreciation rate as a percentage of its original value - E.g. depreciation could be charged at 20% of its original cost 
 
- Or you could be expected to calculate the depreciation using: - The number of years that the non-current asset will be used 
- The expected value of the non-current asset at the end of its working life - This value could be $0 
- The expected value is also called the residual value or the disposal value 
 
 
- This method is usually used when the asset will be equally valuable for each year of its use - For example, fixtures and fittings, equipment, etc 
 

How do I calculate depreciation using the straight line method?
- If you are given the percentage for the depreciation - Find the percentage of the original amount 
- This will be the yearly depreciation charge 
 
- If you are not given the percentage - Calculate the expected loss in value during the expected life of the non-current asset - The original value minus the expected value at the end of its life 
 
- Divide the loss by the number of years it will be used 
- This will be the yearly depreciation charge 
 
Examiner Tips and Tricks
The straight line method is similar to simple interest calculations used in maths.
Worked Example
Abi purchases machinery for $18 000. Machinery is depreciated at 15% per annum using the straight line method.
Calculate the carrying value of the machinery after 3 years.
Answer
- Calculate the yearly expense due to depreciation - 15% ✕ $18 000 = $2 700 
 
- Calculate the total depreciation after 3 years - 3 ✕ $2 700 = $8 100 
 
- Subtract the depreciation from the original value - $18 000 - $8 100 = $9 900 
 
Worked Example
Taiki purchases a vehicle for $30 000. He expects to use the vehicle for 3 years, after which he estimates that it will have a value of $12 000.
Calculate the yearly expense due to the depreciation of the vehicle.
Answer
- Calculate the loss in value over the 3 years - $30 000 - $12 000 = $18 000 
 
- Divide this by the number of years - $18 000 ÷ 3 = $6 000 
 
Reducing balance depreciation
What is the reducing balance method of depreciation?
- The reducing balance method of depreciation assumes that the non-current asset loses value at a rate proportional to its current value - This means that the expense for its depreciation gets smaller each year as the current value decreases 
 
- You will be told the percentage of the current value to use for depreciation 
- This method is usually used when a non-current asset initially loses value at a fast rate 

How do I calculate depreciation using the reducing balance method?
- Find the percentage of the current carrying value - This will be the depreciation charge for that year 
 
- If you need to calculate the depreciation for multiple years, then calculate one year at a time - Find the depreciation charge for one year using the carrying value at that start of the year 
- Subtract this amount from the carrying value at the start of the year to find the new carrying value 
- Find the depreciation charge for the next year using the carrying value at the start of that year 
- Continue this process 
 
- If you just need to find the current carrying value then you can use some maths skills - Subtract the percentage from 100% 
- Write this as a decimal 
- Raise this to the power of the number of years 
- Multiply this by the original value 
 
Examiner Tips and Tricks
The reducing balance method is similar to compound interest calculations used in maths.
Amounts should always be given to the nearest dollar in exams.
Worked Example
Abi purchases a vehicle for $16 000. Machinery is depreciated at 25% per annum using the reducing balance method.
Calculate the carrying value of the machinery after 3 years.
Answer
Find the depreciation charged in each year by finding the percentage of the carrying value at that time.
Subtract that year’s depreciation from the carrying value to find the carrying value at the end of the year.
| End of year | Depreciation charge | Carrying value | 
| 0 | - | $16 000 | 
| 1 | 25% ✕ $16 000 = $4 000 | $16 000 - $4 000 = $12 000 | 
| 2 | 25% ✕ $12 000 = $3 000 | $12 000 - $3 000 = $9 000 | 
| 3 | 25% ✕ $9 000 = $2 250 | $9 000 - $2 250 = $6 750 | 
Alternatively:
- Subtract the percentage from 100% - 100% - 25% = 75% 
 
- Write this as a decimal - 75% = 0.75 
 
- Raise this to the power of the number of years - 0.753 
 
- Multiply this by the original value - $16 000 ✕ 0.753 = $6 750 
 
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