Loan Calculator

Annuity & Differential • Interest-only grace months • Real payment dates from your Start date.

Notes

Grace period: interest-only; principal remains unchanged during grace months.
Annuity: fixed payment after grace; last payment auto-adjusts to clear rounding residue.
Differential: constant principal part (after grace) + declining interest.
Initial deposit: if % > 0, calculator uses Amount × %; else it uses the amount field.
Display rounding = 2 decimals; internal math uses higher precision to minimize residue.
Payment dates advance by whole months from your Start date (e.g., 2025-09-13 → 2025-10-13 → …).