Equal Principal Payment Calculator

Written byOleh Soloninupdated 25 September 2026

Currency

Loan amount

Annual interest rate, %

Term, months

Advanced options

First payment date

For dates in the payment schedule.

Extra repayment

A one-off amount on top of the payment, taken off the balance.

Month of the extra repayment

After the extra repayment

Result

First payment

$2,750.00

Last payment

$1,675.69

Principal in each payment

$1,666.67

Total repaid

$265,541.67

Total interest

$65,541.67

Annuity payment for comparison

$2,270.96

Interest if annuity

$72,515.15

Saved vs annuity

$6,973.48

Payment falls below the annuity

from payment 55 of 120

Working

Principal each month: 200,000.00 ÷ 120 = 1,666.67 First payment: 1,666.67 + 200,000.00 × 0.5417% = 2,750.00 Last payment: 1,666.67 + 1,666.67 × 0.5417% = 1,675.69 Interest: 200,000.00 × 0.5417% × (120 + 1) ÷ 2 = 65,541.67

Payment schedule

  №  Date                Payment      Interest      Principal         Balance
  1  Oct 6, 2026        2,750.00      1,083.33       1,666.67      198,333.33
  2  Nov 6, 2026        2,740.97      1,074.31       1,666.67      196,666.67
  3  Dec 6, 2026        2,731.94      1,065.28       1,666.67      195,000.00
  4  Jan 6, 2027        2,722.92      1,056.25       1,666.67      193,333.33
  5  Feb 6, 2027        2,713.89      1,047.22       1,666.67      191,666.67
  6  Mar 6, 2027        2,704.86      1,038.19       1,666.67      190,000.00
  7  Apr 6, 2027        2,695.83      1,029.17       1,666.67      188,333.33
  8  May 6, 2027        2,686.81      1,020.14       1,666.67      186,666.67
  9  Jun 6, 2027        2,677.78      1,011.11       1,666.67      185,000.00
 10  Jul 6, 2027        2,668.75      1,002.08       1,666.67      183,333.33
 11  Aug 6, 2027        2,659.72        993.06       1,666.67      181,666.67
 12  Sep 6, 2027        2,650.69        984.03       1,666.67      180,000.00
 13  Oct 6, 2027        2,641.67        975.00       1,666.67      178,333.33
 14  Nov 6, 2027        2,632.64        965.97       1,666.67      176,666.67
 15  Dec 6, 2027        2,623.61        956.94       1,666.67      175,000.00
 16  Jan 6, 2028        2,614.58        947.92       1,666.67      173,333.33
 17  Feb 6, 2028        2,605.56        938.89       1,666.67      171,666.67
 18  Mar 6, 2028        2,596.53        929.86       1,666.67      170,000.00
 19  Apr 6, 2028        2,587.50        920.83       1,666.67      168,333.33
 20  May 6, 2028        2,578.47        911.81       1,666.67      166,666.67
 21  Jun 6, 2028        2,569.44        902.78       1,666.67      165,000.00
 22  Jul 6, 2028        2,560.42        893.75       1,666.67      163,333.33
 23  Aug 6, 2028        2,551.39        884.72       1,666.67      161,666.67
 24  Sep 6, 2028        2,542.36        875.69       1,666.67      160,000.00
 25  Oct 6, 2028        2,533.33        866.67       1,666.67      158,333.33
 26  Nov 6, 2028        2,524.31        857.64       1,666.67      156,666.67
 27  Dec 6, 2028        2,515.28        848.61       1,666.67      155,000.00
 28  Jan 6, 2029        2,506.25        839.58       1,666.67      153,333.33
 29  Feb 6, 2029        2,497.22        830.56       1,666.67      151,666.67
 30  Mar 6, 2029        2,488.19        821.53       1,666.67      150,000.00
 31  Apr 6, 2029        2,479.17        812.50       1,666.67      148,333.33
 32  May 6, 2029        2,470.14        803.47       1,666.67      146,666.67
 33  Jun 6, 2029        2,461.11        794.44       1,666.67      145,000.00
 34  Jul 6, 2029        2,452.08        785.42       1,666.67      143,333.33
 35  Aug 6, 2029        2,443.06        776.39       1,666.67      141,666.67
 36  Sep 6, 2029        2,434.03        767.36       1,666.67      140,000.00
 37  Oct 6, 2029        2,425.00        758.33       1,666.67      138,333.33
 38  Nov 6, 2029        2,415.97        749.31       1,666.67      136,666.67
 39  Dec 6, 2029        2,406.94        740.28       1,666.67      135,000.00
 40  Jan 6, 2030        2,397.92        731.25       1,666.67      133,333.33
 41  Feb 6, 2030        2,388.89        722.22       1,666.67      131,666.67
 42  Mar 6, 2030        2,379.86        713.19       1,666.67      130,000.00
 43  Apr 6, 2030        2,370.83        704.17       1,666.67      128,333.33
 44  May 6, 2030        2,361.81        695.14       1,666.67      126,666.67
 45  Jun 6, 2030        2,352.78        686.11       1,666.67      125,000.00
 46  Jul 6, 2030        2,343.75        677.08       1,666.67      123,333.33
 47  Aug 6, 2030        2,334.72        668.06       1,666.67      121,666.67
 48  Sep 6, 2030        2,325.69        659.03       1,666.67      120,000.00
 49  Oct 6, 2030        2,316.67        650.00       1,666.67      118,333.33
 50  Nov 6, 2030        2,307.64        640.97       1,666.67      116,666.67
 51  Dec 6, 2030        2,298.61        631.94       1,666.67      115,000.00
 52  Jan 6, 2031        2,289.58        622.92       1,666.67      113,333.33
 53  Feb 6, 2031        2,280.56        613.89       1,666.67      111,666.67
 54  Mar 6, 2031        2,271.53        604.86       1,666.67      110,000.00
 55  Apr 6, 2031        2,262.50        595.83       1,666.67      108,333.33
 56  May 6, 2031        2,253.47        586.81       1,666.67      106,666.67
 57  Jun 6, 2031        2,244.44        577.78       1,666.67      105,000.00
 58  Jul 6, 2031        2,235.42        568.75       1,666.67      103,333.33
 59  Aug 6, 2031        2,226.39        559.72       1,666.67      101,666.67
 60  Sep 6, 2031        2,217.36        550.69       1,666.67      100,000.00
 61  Oct 6, 2031        2,208.33        541.67       1,666.67       98,333.33
 62  Nov 6, 2031        2,199.31        532.64       1,666.67       96,666.67
 63  Dec 6, 2031        2,190.28        523.61       1,666.67       95,000.00
 64  Jan 6, 2032        2,181.25        514.58       1,666.67       93,333.33
 65  Feb 6, 2032        2,172.22        505.56       1,666.67       91,666.67
 66  Mar 6, 2032        2,163.19        496.53       1,666.67       90,000.00
 67  Apr 6, 2032        2,154.17        487.50       1,666.67       88,333.33
 68  May 6, 2032        2,145.14        478.47       1,666.67       86,666.67
 69  Jun 6, 2032        2,136.11        469.44       1,666.67       85,000.00
 70  Jul 6, 2032        2,127.08        460.42       1,666.67       83,333.33
 71  Aug 6, 2032        2,118.06        451.39       1,666.67       81,666.67
 72  Sep 6, 2032        2,109.03        442.36       1,666.67       80,000.00
 73  Oct 6, 2032        2,100.00        433.33       1,666.67       78,333.33
 74  Nov 6, 2032        2,090.97        424.31       1,666.67       76,666.67
 75  Dec 6, 2032        2,081.94        415.28       1,666.67       75,000.00
 76  Jan 6, 2033        2,072.92        406.25       1,666.67       73,333.33
 77  Feb 6, 2033        2,063.89        397.22       1,666.67       71,666.67
 78  Mar 6, 2033        2,054.86        388.19       1,666.67       70,000.00
 79  Apr 6, 2033        2,045.83        379.17       1,666.67       68,333.33
 80  May 6, 2033        2,036.81        370.14       1,666.67       66,666.67
 81  Jun 6, 2033        2,027.78        361.11       1,666.67       65,000.00
 82  Jul 6, 2033        2,018.75        352.08       1,666.67       63,333.33
 83  Aug 6, 2033        2,009.72        343.06       1,666.67       61,666.67
 84  Sep 6, 2033        2,000.69        334.03       1,666.67       60,000.00
 85  Oct 6, 2033        1,991.67        325.00       1,666.67       58,333.33
 86  Nov 6, 2033        1,982.64        315.97       1,666.67       56,666.67
 87  Dec 6, 2033        1,973.61        306.94       1,666.67       55,000.00
 88  Jan 6, 2034        1,964.58        297.92       1,666.67       53,333.33
 89  Feb 6, 2034        1,955.56        288.89       1,666.67       51,666.67
 90  Mar 6, 2034        1,946.53        279.86       1,666.67       50,000.00
 91  Apr 6, 2034        1,937.50        270.83       1,666.67       48,333.33
 92  May 6, 2034        1,928.47        261.81       1,666.67       46,666.67
 93  Jun 6, 2034        1,919.44        252.78       1,666.67       45,000.00
 94  Jul 6, 2034        1,910.42        243.75       1,666.67       43,333.33
 95  Aug 6, 2034        1,901.39        234.72       1,666.67       41,666.67
 96  Sep 6, 2034        1,892.36        225.69       1,666.67       40,000.00
 97  Oct 6, 2034        1,883.33        216.67       1,666.67       38,333.33
 98  Nov 6, 2034        1,874.31        207.64       1,666.67       36,666.67
 99  Dec 6, 2034        1,865.28        198.61       1,666.67       35,000.00
100  Jan 6, 2035        1,856.25        189.58       1,666.67       33,333.33
101  Feb 6, 2035        1,847.22        180.56       1,666.67       31,666.67
102  Mar 6, 2035        1,838.19        171.53       1,666.67       30,000.00
103  Apr 6, 2035        1,829.17        162.50       1,666.67       28,333.33
104  May 6, 2035        1,820.14        153.47       1,666.67       26,666.67
105  Jun 6, 2035        1,811.11        144.44       1,666.67       25,000.00
106  Jul 6, 2035        1,802.08        135.42       1,666.67       23,333.33
107  Aug 6, 2035        1,793.06        126.39       1,666.67       21,666.67
108  Sep 6, 2035        1,784.03        117.36       1,666.67       20,000.00
109  Oct 6, 2035        1,775.00        108.33       1,666.67       18,333.33
110  Nov 6, 2035        1,765.97         99.31       1,666.67       16,666.67
111  Dec 6, 2035        1,756.94         90.28       1,666.67       15,000.00
112  Jan 6, 2036        1,747.92         81.25       1,666.67       13,333.33
113  Feb 6, 2036        1,738.89         72.22       1,666.67       11,666.67
114  Mar 6, 2036        1,729.86         63.19       1,666.67       10,000.00
115  Apr 6, 2036        1,720.83         54.17       1,666.67        8,333.33
116  May 6, 2036        1,711.81         45.14       1,666.67        6,666.67
117  Jun 6, 2036        1,702.78         36.11       1,666.67        5,000.00
118  Jul 6, 2036        1,693.75         27.08       1,666.67        3,333.33
119  Aug 6, 2036        1,684.72         18.06       1,666.67        1,666.67
120  Sep 6, 2036        1,675.69          9.03       1,666.67            0.00

Payments by year against an annuity

Year       Declining         Annuity     Difference
   1       32,404.17       27,251.51      +5,152.65
   2       31,104.17       27,251.51      +3,852.65
   3       29,804.17       27,251.51      +2,552.65
   4       28,504.17       27,251.51      +1,252.65
   5       27,204.17       27,251.51         -47.35
   6       25,904.17       27,251.51      -1,347.35
   7       24,604.17       27,251.51      -2,647.35
   8       23,304.17       27,251.51      -3,947.35
   9       22,004.17       27,251.51      -5,247.35
  10       20,704.17       27,251.51      -6,547.35

This result is informational only and is not professional advice.

Falling loan payments, the schedule and how they compare with equal payments

Loan with equal principal payments and falling instalments: a full schedule of payment, interest, principal and balance, the formula with your numbers, a year-by-year comparison with an annuity, the month the payment drops below it, and an extra repayment.

With equal principal payments, sometimes called a declining or differentiated schedule, the loan is repaid in equal slices of principal and interest is charged on what is left. The first payment is the largest and each one after it is smaller. The calculator builds that schedule and totals the interest.

Alongside it is an annuity, the usual equal-payment loan, for the same amount and term: its payment, its interest, and the month from which the falling payment becomes the smaller of the two. A first payment date and a one-off extra repayment can be added in the extra settings.

How to use

Enter the loan amount, the yearly rate and the term in months.
In the extra settings add the first payment date to put dates in the schedule.
For an extra repayment, enter the amount, the month and whether to shorten the term or lower the payments.
Read the first and last payment, the interest, the annuity comparison, the Working lines and the schedule.

The equal principal payment formula

Each month you repay the same share of the loan, the amount ÷ number of months, plus interest on the balance: payment = S ÷ n + balance × i, where i is the monthly rate (yearly rate ÷ 12). The first payment is S ÷ n + S × i, the last is S ÷ n × (1 + i), and the total interest is S × i × (n + 1) ÷ 2.

For 200,000 at 6.5% over 120 months the principal in every payment is 1,666.67 and the monthly rate 0.5417%. The first payment is 1,666.67 + 1,083.33 = 2,750.00, the last 1,675.69, and the interest 200,000 × 0.5417% × 121 ÷ 2 = 65,541.67.

200,000 at 6.5% a year over 120 months. The full schedule is in the result. Worked out with this calculator.
No.	Payment	Interest	Principal	Balance
1	2,750.00	1,083.33	1,666.67	198,333.33
2	2,740.97	1,074.31	1,666.67	196,666.67
3	2,731.94	1,065.28	1,666.67	195,000.00
…
119	1,684.72	18.06	1,666.67	1,666.67
120	1,675.69	9.03	1,666.67	0.00

Equal principal against an annuity

With an annuity the payment stays the same, and the interest share starts high and shrinks. For the same loan the annuity payment is 2,270.96 and the interest 72,515.15, which is 6,973.48 more than with equal principal payments. The falling payment is higher at first and drops below the annuity from payment 55.

Equal principal payments cost less because the balance falls faster, so interest is charged on less. The price is heavier payments early on: 5,152.65 more than the annuity in the first year.

Payments per year: 200,000 at 6.5% over 120 months. Worked out with this calculator.
Year	Equal principal	Annuity	Difference
1	32,404.17	27,251.51	+5,152.65
3	29,804.17	27,251.51	+2,552.65
5	27,204.17	27,251.51	−47.35
7	24,604.17	27,251.51	−2,647.35
10	20,704.17	27,251.51	−6,547.35

How much less interest you pay

The gap grows with the rate and the term. At 6.5% it is 1,752.11 over five years, 6,973.48 over ten, 27,333.44 over twenty and 59,547.31 over thirty, when the first payment is 1,638.89 against an annuity of 1,264.14.

200,000 at 6.5% a year. Worked out with this calculator.
Term	First payment	Annuity	Interest	Saved against annuity
5 years	4,416.67	3,913.23	33,041.67	1,752.11
10 years	2,750.00	2,270.96	65,541.67	6,973.48
20 years	1,916.67	1,491.15	130,541.67	27,333.44
30 years	1,638.89	1,264.14	195,541.67	59,547.31

An extra repayment

A one-off extra payment cuts the balance, so interest runs on less from then on. If you shorten the term, the monthly principal stays the same and the loan ends sooner: 20,000 in month 12 brings the term from 120 to 108 months and the interest from 65,541.67 to 54,437.50. If you lower the payments instead, the balance is spread over the remaining months and the interest falls to 59,637.50.

How a lender recalculates after a partial repayment is set by your loan agreement, so check the result against the new schedule you are given.

What this calculator shows

The first and last payment, the principal in each payment and the total interest
The annuity payment, its interest and how much equal principal saves
The month from which the falling payment is below the annuity
A payment schedule with interest, principal, balance and dates
The effect of an extra repayment on the term or the payments

What to keep in mind

The rate is fixed and monthly interest is the balance × yearly rate ÷ 12, not by days in the month.
The last payment clears whatever is left; amounts are rounded to cents only for display.
Insurance and fees are not included.

FAQs

How do I calculate an equal principal loan payment?

Payment = loan amount ÷ months + balance × monthly rate. For 200,000 at 6.5% over 120 months the first payment is 1,666.67 + 1,083.33 = 2,750.00 and the last 1,675.69.

How much interest does an equal principal loan cost?

Total interest = S × i × (n + 1) ÷ 2, with i the monthly rate. 200,000 × 0.5417% × 121 ÷ 2 = 65,541.67 over 120 months at 6.5% a year.

Which is cheaper, equal principal or an annuity?

Equal principal, by total interest: 65,541.67 against 72,515.15 in the example. The early payments are higher, though: 2,750.00 against 2,270.96, and 5,152.65 more over the first year.

When does the falling payment drop below the annuity?

Before the middle of the term. For 200,000 at 6.5% over 120 months it is from payment 55; over 30 years, from payment 126 of 360. The calculator shows the month for your loan.

Why does the payment go down every month?

The principal in each payment is the same while interest is charged on a shrinking balance. In the example interest falls by 9.03 a month, and so does the payment.

Is it better to shorten the term or lower the payment after an extra repayment?

Shortening the term saves more interest. 20,000 extra in month 12 on the example loan saves 11,104.17 if the term is cut, and 5,904.17 if the payments are lowered.

What is a differentiated payment?

Another name for equal principal payments: the principal part is fixed and the payment falls as interest on the balance shrinks.

Worked example

200,000 over ten years

Input: 200,000 at 6.5% a year over 120 months

Output: First payment 2,750.00, last 1,675.69, total interest 65,541.67

Note: An annuity would be 2,270.96 a month with 72,515.15 of interest: 6,973.48 more, but the payment never changes.

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