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Simulate an adjustable-rate loan

This page allows you to enter data for an adjustable-rate (or variable-rate) loan, tied to an interest rate change simulation.

Use the following data entry form to specify the terms (or the closest corresponding terms) of the loan.

  Enter the terms of your loan  
  Type of loan : Adjustable rate  
  Borrowed amount : $  
  Loan duration :
  Frequency :  
  First payment date :
  Type of interest rate :
  Annual interest rate  
  Initial rate : %  
  Maximum rate :  
  Minimum rate :  
  Minimum rate adjustment :  
  Maximum rate adjustment :  
  Rate adjustment frequency  
  The first time after :  
  then, every :  
  Changes in the payment amount  
  Increase in the payment amount :  
  Maximum loan extension :  
  Rate adjustment function  
  Curve :  
  Amplitude of the rate change :  
  Cycle length :  

Guide to the information specific to this form

Annual interest rate Enter the initial interest rate. If the rate is capped, enter the maximum and/or minimum possible rate. The minimum rate adjustment is the minimum increase (or decrease) needed from the base rate in order for the rate adjustment to take effect. The maximum rate adjustment is the largest amount by which the interest rate may be increased or decreased.

Rate adjustment frequency Enter the time period before the first adjustment is made, and the frequency of subsequent adjustments.

Changes in the payment amount With adjustable-rate loans, the payment amount typically changes when the interest rate changes, so that the overall duration of the loan remains constant. This is the default setting.
In the drop-down box, you can set a limit for the percent change in the payment amount, or prevent it from changing at all (constant amount). However, if you select the constant amount option, a maximum loan extension must be specified. Please note that once the maximum extension is reached, the simulation will continue under the default setting; that is, the payment amounts will be automatically calculated to preserve the new loan duration.

Interest rate adjustment function – Two interest rate curve options are available, which vary the interest rate ‘%’, as a function of time ‘t’. For each curve, you can specify the amplitude of the rate change ‘A’, and the cycle length ‘C’. Interest rate adjustment function – Two interest rate curve options are available, which vary the interest rate ‘%’, as a function of time ‘t’. For each curve, you can specify the amplitude of the rate change ‘A’, and the cycle length ‘C’.

Linear curve Sine curve
Scenario de progression lineaire Scenario de variation sinusoidale

Linear curve – This simulates a rate increase over the cycle period ‘C’. At the end of the cycle, the rate stays at the new higher level. This curve is used primarily for short cycles (5 or 10 years).

Sine curve – This simulates successive interest rate increases and decreases. With this type of curve, you can select a starting point (marked 0 to 5), which is important because it fixes where, in the interest rate cycle, your initial rate is. For instance, select 0 if you feel rates are at historically low levels, 1 or 2 if rates have come off a low and should continue to rise, 3 or 4 if rates have reached a high and are expected to fall, or 5 if rates are decreasing. This curve is best for long cycles (20 or 30 years).

For both functions, the minimum possible annual interest rate is 0.5%.

To simulate an existing adjustable-rate loan – If you want to simulate an existing loan, save it without an interest rate curve (“None” in the drop-down menu). You will later be able to change the rate and payment amount manually.

Guide to the general information

Payment frequency – For annual, semi-annual (half-year), quarterly, monthly, and semi-monthly (twice-monthly) payments, the loan calculation is performed per 12, 6, 3, 1, or ½ month period, respectively, and the loan duration should be a whole multiple of its corresponding period (for example, for quarterly payments, the loan duration may be 3 months or 6 months, but not 5 months).

Payment frequency – For weekly or bi-weekly (15-day) payments, the loan calculation is performed assuming that 1 year consists of 52 weeks with 7 days each, or of 26 periods with 14 days each. The actual payment period will be shorter than the one entered. The loan duration should be a 3-month multiple.

Compound interest rate / simple interest rate – For most cases, the simple interest rate should be used. Interest rate types and calculation methods vary according to country and use, and occasionally according to the purposes of the loan (e.g., property vs. personal). If the simulation results do not match the payment schedule provided by your bank, then it may be necessary to use the other type of interest rate. For a detailed discussion of the various interest rates, see Wikipedia Interest.

First payment due date – Dates entered are truncated to the last day of the month, but the date as entered will be used for subsequent months. For payment periods consisting of multiple months, the first payment due date will be used for the other due dates. For example, a first payment set at 2-30 will lead to due dates on 2-28, 3-30, 4-30, etc.

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