Loan repayment (installments)

Build an amortization schedule with equal-payment, equal-principal, rate changes, payment frequency, and grace periods.

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Calculation specification

Reviewed on:

Formula basis

For an annuity loan, PMT=P×i/{1−(1+i)^−n}, or P/n when i=0. Equal-principal mode divides the outstanding balance across the remaining periods and adds that period's interest; the selected yen rounding is applied period by period.

Calculation method

Builds a repayment schedule from principal, repayment method, payment frequency, one rate-change boundary, term, and an optional principal-grace period.

Exclusions and checks required

  • The rate changes only once at the entered boundary; contractual variable-rate review or payment-cap rules are not modeled.
  • Fees, insurance, guarantees, arrears, business-day adjustments, and lender-specific rounding are excluded.
  • During the grace period only interest is paid, and the final row is adjusted to clear the modeled balance.

Example input:：A JPY 30 million monthly loan over 35 years

principalMan
3000
method
annuity
rounding
floor
frequency
monthly
initialRate
1.5
initialYears
10
laterRate
2
termYears
35
termMonths
0
startMonth
2026-07
graceMonths
0

This is a mathematical schedule under the entered rate and rounding choices, not a lender's contractual statement.

FAQ

Who is this calculator for? Loan repayment (installments)

Build an amortization schedule with equal-payment, equal-principal, rate changes, payment frequency, and grace periods.

What values should I enter?

Applies to: Loan repayment / Annuity payment: PMT = P × i ÷ (1 − (1+i)^−n)

How should I interpret this estimate?

Builds a repayment schedule from principal, repayment method, payment frequency, one rate-change boundary, term, and an optional principal-grace period.

How to use

  1. Enter your input values and press Calculate.
  2. Review the result and compare it with expected context.
  3. For an annuity loan, PMT=P×i/{1−(1+i)^−n}, or P/n when i=0. Equal-principal mode divides the outstanding balance across the remaining periods and adds that period's interest; the selected yen rounding is applied period by period.