Sinking Fund Formula

Definition of Sinking Fund Formula

A sinking fund refers to a fund that is set up by the particular bond issuer in order to repurchase a definite portion of the bond issue or for the replenishment of a major asset or any other similar capital expenditureCapital ExpenditureCapex or Capital Expenditure is the expense of the company's total purchases of assets during a given period determined by adding the net increase in factory, property, equipment, and depreciation expense during a fiscal more. As such, the bond issuer is required to contribute a certain amount of money to the sinking fund each period, and the formula to calculate the sinking fund is as shown below.

Sinking Fund, A= [(1+(r/m))n*m-1] / (r/m) * P


  • P = Periodic contribution to the sinking fund,
  • r = Annualized rate of interest,
  • n = No. of years
  • m = No. of payments per year

You are free to use this image on your website, templates etc, Please provide us with an attribution linkHow to Provide Attribution?Article Link to be Hyperlinked
For eg:
Source: Sinking Fund Formula (

And the formula for the periodic contribution to the sinking fund can be represented as,

Periodic Contribution, P = (r/m) / [(1+(r/m))n*m-1] * A

Calculation of Sinking Fund (Step by Step)

  1. Firstly, determine the required periodic contribution to be made to the sinking fund as per the company strategy. The periodic contribution is denoted by P.

  2. Now, the annualized rate of interest of the fund and the frequency of the periodic payment has to be determined, which are denoted by r and m, respectively. Then the periodic interest rate is computed by dividing the annualized interest rate by the number of pay per year. i.e Periodic interest rate = r / m

  3. Now, the number of years has to be determined, and it is denoted by n. Then the total number of periods is computed by multiplying the number of years and the frequency of payments in a year. i.e Total number of periods = n * m

  4. Finally, the calculation of the sinking fund can be done by using the periodic interest rate (step 2) and the total number of periods (step 3), as shown above.


You can download this Sinking Fund Formula Excel Template here – Sinking Fund Formula Excel Template

Example #1

Let us take an example of a sinking fund with a monthly periodic contribution of $1,500. The fund will be required to retire a newly taken debt (zero-coupon bonds) raised for the ongoing expansion project. Do the calculation of the amount of the sinking fund if the annualized rate of interest is 6%, and the debt will be repaid in 5 years.

Use the following data for the calculation of the Sinking Fund.

sinking fund formula example 1.1

Therefore, the calculation of the amount of the sinking fund is as follows,

sinking fund formula example 1.2
  • Sinking Fund = ((1+6%/12) ^(5-12) – 1)/(6%/12) * $1,500

Sinking Fund will be –

sinking fund formula example 1.3
  • Sinking Fund = $104,655.05 ~ $104,655

Therefore, the company will require a sinking fund of $104,655 to retire the entire debt five years from now.

Example #2

Let us take an example of a company ABC Ltd which has raised funds in the form of 1,000 zero-coupon bonds worth $1,000 each. The company wants to set up a sinking fund for repayment of the bonds, which will be after 10 years. Determine the amount of the periodic contribution if the annualized rate of interest is 5%, and the contribution will be done half-yearly.

First, do the calculation of the Sinking Fund Required for the calculation of Periodic Contribution.

example 2.1 - Periodic contribution data
  • Given, Sinking fund, A = Par value of bond * No. of bonds
  • = $1,000 * 1,000 = $1,000,000

Use the following data for the calculation of Periodic Contribution.

example 2.2 - Periodic contribution calculate

Therefore, the amount of the periodic contribution can be calculated using the above formula as,

example 2.3 - Periodic contribution calculation
  • Periodic contribution = (5%/2)/((1+5%/2)^(10*2) -1) * $1,000,000

The periodic contribution will be –

example 2.4 - Periodic contribution result
  • Periodic contribution = $39,147.13 ~ $39,147

Therefore, the company will be required to contribute a sum of $39,147 half-yearly in order to build the sinking fund to retire the zero-coupon bondsZero-coupon BondsIn contrast to a typical coupon-bearing bond, a zero-coupon bond (also known as a Pure Discount Bond or Accrual Bond) is a bond that is issued at a discount to its par value and does not pay periodic interest. In other words, the annual implied interest payment is included into the face value of the bond, which is paid at maturity. As a result, this bond has only one return: the payment of the nominal value at more after 10 years.

Relevance and Uses

From the point of view of an investor, a sinking fund can be beneficial in three major ways-

  1. The interim retirement of debt results in lower principal outstanding that makes the final repayment much more comfortable and likely. This lowers the risk of default.
  2. In case the rate of interest increases, which lowers the bond prices, an investor gets some downside riskDownside RiskDownside Risk is a statistical measure to calculate the loss in a security’s value due to variations in the market conditions. Also, it refers to the uncertainty level of realized returns being much lesser than the anticipated ones. read more protection because the issuer is required to redeem a certain portion of these bonds. The redemption is executed at the sinking fund call price, which is usually fixed at the par value.
  3. A sinking fund is required to maintain liquidity of the bonds in the secondary marketSecondary MarketA secondary market is where securities are offered to the general public after being offered in the primary market. Such securities are usually listed on the stock exchange. A significant portion of trading happens in such a market and are of two types – equities and debt more by acting as a buyer. When the interest rates increase, leading to a lower value for the bonds, this provision benefits the investors because the issuers have to buy the bonds even if the prices fall.

However, there are several disadvantages too for the investors-

  1. If the bond prices increase due to a decrease in interest rate, the investor’s upside may end up limited because of the compulsory redemption mandated for the sinking fund of the bondSinking Fund Of The BondA bond sinking fund refers to the sum a company sets aside for repurchasing its bonds or meeting the related future obligations. Thus, the company saves money with an independent trustee at frequent intervals until the bonds' more. This means that the investors would receive the fixed sinking-fund price for their bonds despite the fact that the bonds are priced higher in the open market.
  2. Further, the investors might end up reinvesting their money elsewhere at a lower rate due to the sinking fund provisions in a market with a declining interest rate.

For issuers, the sinking fund acts as credit enhancementCredit EnhancementCredit enhancement is a strategy used by businesses to increase their creditworthiness through a variety of internal and external measures. The fundamental goal is to obtain better debt repaying terms, hence lowering investors' risk of specific structured products in the financial more and, as such, enables companies to borrow cheaply. Consequently, bonds with sinking funds often offer lower yields than similar bonds without sinking funds because of lower default risk and downside protection.

Recommended Articles

This has been a guide to Sinking Fund Formula. Here we discuss how to calculate the sinking fund using its formula along with the practical examples and downloadable excel sheet. You can learn more about accounting from the following articles –

Reader Interactions

Leave a Reply

Your email address will not be published. Required fields are marked *