Amortization

What Is Amortization?

Amortization is an accounting technique used to periodically lower the book value of a loan or an intangible asset over a set period of time. Concerning a loan, amortization focuses on spreading out loan payments over time. When applied to an asset, amortization is similar to depreciation.

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Key Takeaways

  • Amortization typically refers to the process of writing down the value of either a loan or an intangible asset.
  • Amortization schedules are used by lenders, such as financial institutions, to present a loan repayment schedule based on a specific maturity date.
  • Intangibles are amortized (expensed) over time to tie the cost of the asset to the revenues it generates, in accordance with the matching principle of generally accepted accounting principles (GAAP).
  • Negative amortization may happen when the payments of a loan are lower than the accumulated interest, causing the borrower to owe more money instead of less.
  • Most accounting and spreadsheet software have functions that can calculate amortization automatically.
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Amortization

Understanding Amortization

The term “amortization” refers to two situations. First, amortization is used in the process of paying off debt through regular principal and interest payments over time. An amortization schedule is used to reduce the current balance on a loan—for example, a mortgage or a car loan—through installment payments.

Second, amortization can also refer to the practice of spreading out capital expenses related to intangible assets over a specific duration—usually over the asset’s useful life—for accounting and tax purposes.

Amortization of Loans

Amortization can refer to the process of paying off debt over time in regular installments of interest and principal sufficient to repay the loan in full by its maturity date. A higher percentage of the flat monthly payment goes toward interest early in the loan, but with each subsequent payment, a greater percentage of it goes toward the loan’s principal.

Amortization can be calculated using most modern financial calculators, spreadsheet software packages (such as Microsoft Excel), or online amortization calculators. Amortization schedules begin with the outstanding loan balance. To arrive at the amount of monthly payments, the interest payment is calculated by multiplying the interest rate by the outstanding loan balance and dividing by 12. The amount of principal due in a given month is the total monthly payment (a flat amount) minus the interest payment for that month.

For the next month, the outstanding loan balance is calculated as the previous month’s outstanding balance minus the most recent principal payment. The interest payment is once again calculated off the new outstanding balance, and the pattern continues until all principal payments have been made, and the loan balance is zero at the end of the loan term.

Accountants use amortization to spread out the costs of an asset over the useful lifetime of that asset.

How to Calculate Amortization of Loans

The formula to calculate the monthly principal due on an amortized loan is as follows:

Principal Payment = TMP ( OLB × Interest Rate 12 Months ) where: TMP = Total monthly payment OLB = Outstanding loan balance \begin{aligned}&\text{Principal Payment} = \text{TMP} - \Big ( \text{OLB} \times \frac { \text{Interest Rate} }{ \text{12 Months} } \Big ) \\&\textbf{where:} \\&\text{TMP} = \text{Total monthly payment} \\&\text{OLB} = \text{Outstanding loan balance} \\\end{aligned} Principal Payment=TMP(OLB×12 MonthsInterest Rate)where:TMP=Total monthly paymentOLB=Outstanding loan balance

Typically, the total monthly payment is specified when you take out a loan. However, if you are attempting to estimate or compare monthly payments based on a given set of factors, such as loan amount and interest rate, then you may need to calculate the monthly payment as well. If you need to calculate the total monthly payment for any reason, the formula is as follows:

Total Payment = Loan Amount × [ i × ( 1 + i ) n ( 1 + i ) n 1 ] where: i = Monthly interest payment n = Number of payments \begin{aligned}&\text{Total Payment} = \text{Loan Amount} \times \Bigg [ \frac { i \times (1 + i) ^n }{ (1 + i)^n - 1 } \Bigg ] \\&\textbf{where:} \\&i = \text{Monthly interest payment} \\&n = \text{Number of payments} \\\end{aligned} Total Payment=Loan Amount×[(1+i)n1i×(1+i)n]where:i=Monthly interest paymentn=Number of payments

You’ll need to divide your annual interest rate by 12. For example, if your annual interest rate is 3%, then your monthly interest rate will be 0.25% (0.03 annual interest rate ÷ 12 months). You'll also multiply the number of years in your loan term by 12. For example, a four-year car loan would have 48 payments (four years × 12 months).

Amortization of Intangible Assets

Amortization can also refer to the amortization of intangibles. In this case, amortization is the process of expensing the cost of an intangible asset over the projected life of the asset. It measures the consumption of the value of an intangible asset, such as goodwill, a patent, a trademark, or copyright.

Amortization is calculated in a similar manner to depreciation—which is used for tangible assets, such as equipment, buildings, vehicles, and other assets subject to physical wear and tear—and depletion, which is used for natural resources. When businesses amortize expenses over time, they help tie the cost of using an asset to the revenues that it generates in the same accounting period, in accordance with generally accepted accounting principles (GAAP). For example, a company benefits from the use of a long-term asset over a number of years. Thus, it writes off the expense incrementally over the useful life of that asset.

The amortization of intangibles is also useful in tax planning. The Internal Revenue Service (IRS) allows taxpayers to take a deduction for certain expenses: geological and geophysical expenses incurred in oil and natural gas exploration, atmospheric pollution control facilities, bond premiums, research and development (R&D), lease acquisition, forestation and reforestation, and intangibles, such as goodwill, patents, copyrights, and trademarks.

The IRS has schedules that dictate the total number of years in which to expense tangible and intangible assets for tax purposes.

Why Is Amortization Important?

Amortization is important because it helps businesses and investors understand and forecast their costs over time. In the context of loan repayment, amortization schedules provide clarity into what portion of a loan payment consists of interest versus principal. This can be useful for purposes such as deducting interest payments for tax purposes.

Amortizing intangible assets is important because it can reduce a business's taxable income, and therefore its tax liability, while giving investors a better understanding of the company’s true earnings.

Example of Amortization

Let’s look at a four-year, $30,000 auto loan at 3% interest. The monthly payment is going to be $664.03. That is arrived at as follows:

$ 30 , 000 × ( 0.0025 × ( 1.0025 ÷ 48 ) 1.0025 ÷ 48 1 ) \begin{aligned}&\$30,000 \times \Bigg ( \frac { 0.0025 \times (1.0025 \div 48) }{ 1.0025 \div 48 } - 1 \Bigg ) \\\end{aligned} $30,000×(1.0025÷480.0025×(1.0025÷48)1)

In the first month, $75 of the $664.03 monthly payment goes to interest.

$ 30 , 000  loan balance × 3 %  interest rate ÷ 12  months \begin{aligned}&\$30,000 \ \text{loan balance} \times 3\% \ \text{interest rate} \div 12 \ \text{months} \\\end{aligned} $30,000 loan balance×3% interest rate÷12 months

The remaining $589.03 goes toward principal.

$ 664.03  total monthly payment $ 75  interest payment \begin{aligned}&\$664.03 \ \text{total monthly payment} - \$75 \ \text{interest payment} \\ \end{aligned} $664.03 total monthly payment$75 interest payment

The total payment stays the same each month, while the portion going to principal increases and the portion going to interest decreases. In the final month, only $1.66 is paid in interest, because the outstanding loan balance at that point is very minimal compared with the starting loan balance.

Loan Amortization Schedule
Period Total Payment Due Computed Interest Due Principal Due Principal Balance
        $30,000
1 $664.03 $75 $589.03 $29,410.97
2 $664.03 $73.53 $590.50 $28,820.47
3 $664.03 $72.05 $591.98 $28,228.49
4 $664.03 $70.57 $593.46 $27,635.03
5 $664.03 $69.09 $594.94 $27,040.09
6 $664.03 $67.60 $596.43 $26,443.66
7 $664.03 $66.11 $597.92 $25,845.74
8 $664.03 $64.61 $599.42 $25,246.32
9 $664.03 $63.12 $600.91 $24,645.41
10 $664.03 $61.61 $602.42 $24,042.99
11 $664.03 $60.11 $603.92 $23,439.07
12 $664.03 $58.60 $605.43 $22,833.64
13 $664.03 $57.08 $606.95 $22,226.69
14 $664.03 $55.57 $608.46 $21,618.23
15 $664.03 $54.05 $609.98 $21,008.24
16 $664.03 $52.52 $611.51 $20,396.73
17 $664.03 $50.99 $613.04 $19,783.69
18 $664.03 $49.46 $614.57 $19,169.12
19 $664.03 $47.92 $616.11 $18,553.02
20 $664.03 $46.38 $617.65 $17,935.37
21 $664.03 $44.84 $619.19 $17,316.18
22 $664.03 $43.29 $620.74 $16,695.44
23 $664.03 $41.74 $622.29 $16,073.15
24 $664.03 $40.18 $623.85 $15,449.30
25 $664.03 $38.62 $625.41 $14,823.89
26 $664.03 $37.06 $626.97 $14,196.92
27 $664.03 $35.49 $628.54 $13,568.38
28 $664.03 $33.92 $630.11 $12,938.28
29 $664.03 $32.35 $631.68 $12,306.59
30 $664.03 $30.77 $633.26 $11,673.33
31 $664.03 $29.18 $634.85 $11,038.48
32 $664.03 $27.60 $636.43 $10,402.05
33 $664.03 $26.01 $638.02 $9,764.02
34 $664.03 $24.41 $639.62 $9,124.40
35 $664.03 $22.81 $641.22 $8,483.18
36 $664.03 $21.21 $642.82 $7,840.36
37 $664.03 $19.60 $644.43 $7,195.93
38 $664.03 $17.99 $646.04 $6,549.89
39 $664.03 $16.37 $647.66 $5,902.24
40 $664.03 $14.76 $649.27 $5,252.96
41 $664.03 $13.13 $650.90 $4,602.06
42 $664.03 $11.51 $652.52 $3,949.54
43 $664.03 $9.87 $654.16 $3,295.38
44 $664.03 $8.24 $655.79 $2,639.59
45 $664.03 $6.60 $657.43 $1,982.16
46 $664.03 $4.96 $659.07 $1,323.09
47 $664.03 $3.31 $660.72 $662.36
48 $664.03 $1.66 $662.36 $0.00

What Is Negative Amortization?

Negative amortization is when the size of a debt increases with each payment, even if you pay on time. This happens because the interest on the loan is greater than the amount of each payment. Negative amortization is particularly dangerous with credit cards, whose interest rates can be as high as 20% or even 30%. In order to avoid owing more money later, it is important to avoid over-borrowing and to pay your debts as quickly as possible.

What Does Amortization Mean for Intangible Assets?

Amortization measures the declining value of intangible assets, such as goodwill, trademarks, patents, and copyrights. This is calculated in a similar manner to the depreciation of tangible assets, like factories and equipment. When businesses amortize intangible assets over time, they are able to tie the cost of those assets with the revenue generated over each accounting period and deduct the costs over the lifetime of the asset.

Why Is Amortization Important in Accounting?

Amortization helps businesses and investors understand and forecast their costs over time. In the context of loan repayment, amortization schedules provide clarity into what portion of a loan payment consists of interest versus principal. This can be useful for purposes such as deducting interest payments for tax purposes. Amortizing intangible assets is also important because it can reduce a company’s taxable income and therefore its tax liability, while giving investors a better understanding of the company’s true earnings.

What Is the Difference Between Amortization and Depreciation?

Amortization and depreciation are similar concepts, in that both attempt to capture the cost of holding an asset over time. The main difference between them, however, is that amortization refers to intangible assets, whereas depreciation refers to tangible assets. Examples of intangible assets include trademarks and patents; tangible assets include equipment, buildings, vehicles, and other assets subject to physical wear and tear.

Article Sources
Investopedia requires writers to use primary sources to support their work. These include white papers, government data, original reporting, and interviews with industry experts. We also reference original research from other reputable publishers where appropriate. You can learn more about the standards we follow in producing accurate, unbiased content in our editorial policy.
  1. Consumer Finance Protection Bureau. "What Is Amortization and How Could It Affect My Auto Loan?"

  2. Internal Revenue Service. “Instructions for Form 4562."

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