Finance & Investment Calculators

Planning a loan starts with picking a repayment method. The loan interest calculator compares monthly payments and total interest between equal-installment and equal-principal repayment, and the mortgage limit calculator estimates how much you can actually borrow using LTV and DSR ratios. If you're planning to repay early, the prepayment fee calculator shows the penalty in advance.

The jeonse-monthly rent converter applies the standard conversion rate when switching a jeonse deposit into monthly rent or back, and the savings interest and compound interest calculators let you compare how much the maturity payout differs between simple and compound growth.

The base rate history page lists Bank of Korea base rate changes year by year from 2017 through 2026, useful for understanding why loan and deposit rates sit where they do. The inflation calculator adjusts asset value for inflation, and the stock average calculator works out the average buy price and return rate across multiple purchases.

Comparing loans on the headline rate alone misses the real burden. At the same rate, equal-instalment repayment keeps the monthly figure flat while equal-principal front-loads payments and costs less in total interest — the latter favours anyone planning early repayment.

Limits are set separately from rates. A mortgage faces both LTV, the ratio to collateral value, and DSR, the ratio of debt service to income; whichever binds harder sets the limit, so low income can cap borrowing even with ample collateral.

Deposits and instalment savings pay differently at the same rate. A lump-sum deposit sits for the full term while each instalment sits for a different length, so a higher instalment rate often yields less interest than a plain deposit.

Interest is subject to withholding of income tax and local income tax. The after-tax figure is the real return, and financial income above the threshold is aggregated with other income for global taxation.

The base rate feeds into deposit and lending rates with a lag. Variable-rate loans move with their reference index, so in a rising-rate period it is worth computing the gap against a fixed rate in advance.

Real return only appears once inflation is removed: nominal return less inflation gives purchasing-power terms, and subtracting tax leaves what is actually gained. The longer the horizon, the wider that gap.

Early repayment fees apply when a loan is settled before maturity. They are commonly waived after three years and typically taper with the remaining term, so refinancing decisions need the fee weighed against the rate difference.

Comparing jeonse and monthly rent turns on the conversion rate applied when a deposit becomes rent. A statutory ceiling exists but does not bind new contracts, and the honest comparison sets the interest a deposit would earn against the rent burden.

Compounding gains force over time. Dividing 72 by the annual return approximates the years to double, and the same rule applied to inflation shows purchasing power growing more slowly than the headline suggests.

Instalment and lump-sum investing differ at the same total. Each instalment sits for a different length, so later contributions earn interest for less time — the case for instalments rests on spreading entry points, not on return.