Equal Payment vs Equal Principal: Monthly Installments, Interest and Who Should Pick Which
Equal-payment (annuity) and equal-principal are the two mainstream mortgage repayment methods. Borrowing the same 1 million over 30 years at the same rate, their total interest can differ by well over a hundred thousand — yet the interest-saving method demands higher payments early on. Neither is simply better; they are two strategies for distributing repayment pressure across time.
| Dimension | Equal Payment (annuity) | Equal Principal |
|---|---|---|
| Payment shape | Fixed every month, identical across the whole term — easy household budgeting | Declining monthly: highest first installment, then slightly less each month, easing over time |
| Total interest | Higher: principal returns slowly and money stays borrowed longer, so total interest is clearly larger under the same rate and term | Lower: principal falls fast and interest accrues only on the remaining balance, saving substantially in the long run |
| Early-term pressure | Low: starting installments sit near the term's minimum, friendlier for families whose income is still ramping up | High: first installments can run 20–30% above annuity payments, a real test of cash flow |
| Calculation | Annuity formula: a fixed monthly blend of principal plus interest, interest-heavy at first and principal-light | Linear split: a fixed slice of principal monthly, with interest settled separately on the remaining balance — transparent logic |
| Prepayment impact | Early payments are mostly interest; clearing the loan within a few years feels like paying much but moving the principal little | Principal declines steadily from day one, so any prepayment directly saves future interest with crystal-clear accounting |
| Who fits | Young families with stable but tight income today, and anyone who wants to lock in low installments expecting inflation | Borrowers with strong current income who minimize total cost or plan to prepay deliberately |
| Bank default | Most banks default to it: fixed installments simplify risk assessment and flatten default-probability curves | Usually requires asking explicitly; some banks offer it only to certain first-home customers |
When to choose Equal Payment (annuity)
If you are mid-career on the way up, need cash for living costs and emergencies now, or believe tomorrow's money is worth less than today's, equal payment's steady low installments buy the smoothest life rhythm — and it is the only plan where budgeting never needs recalculating.
When to choose Equal Principal
If household income comfortably exceeds the required installments, savings rates lose to your mortgage rate, or you have a concrete prepayment plan, equal principal trades a higher starting point for lower total interest. Mathematically it is the minimal-cost solution — provided early cash flow can carry it.
Related online tools
Loan Calculator — Monthly Payment & Total Interest
Online loan calculator with equal installment and equal principal modes showing monthly payment, interest and totals for mortgage planning.
Car Loan Calculator | Payment & Total Cost
Car loan calculator: price, down payment, rate and term in, monthly payment and total cost out, with down payment breakdown.
Wangshangdai Loan Interest Calculator
Wangshangdai interest calculator converting daily rate to APR: principal and term in, total interest out.
FAQ
Is equal payment really a worse deal than equal principal?
Not inherently. The two methods occupy funds for different durations while the rate treats both equally; the difference comes from repayment pacing, not a bank trick. If you invest the saved installment gap at a return above the mortgage rate, annuity can even win.
Can I switch from equal payment to equal principal later?
Most banks allow switching mid-loan, typically processed like a prepayment event with a small fee; remaining-term installments are recalculated under the new method.
Do housing fund loans also offer both methods?
Yes, housing-fund and commercial loans both support the two methods with identical rules. Lower housing-fund rates shrink the interest gap, but equal principal still saves more.
Going deeper
A concrete closing example: 1 million principal, 30 years, 4% annual rate. Equal payment runs about ¥4,774 monthly with roughly ¥720k total interest; equal principal starts near ¥6,111, ends near ¥2,789, and totals about ¥600k — a gap of some ¥120k. But remember that gap is not a free discount: it is time value you buy by repaying over a thousand yuan extra each month early on. When undecided, use our online loan calculators to compute both plans side by side with your real amount and term before deciding.