When rates fall, refinancing (转按揭) replaces your current mortgage with a new one at a lower rate — for a price. This calculator compares both loans side by side: monthly payment, interest over each lifetime, and the break-even point where the closing costs pay for themselves.
The same-term rows isolate the pure effect of the rate cut. If the new loan also stretches the term, part of the monthly saving is just re-amortising the same debt over more months — the same-term comparison strips that out.
Frequently asked questions
When is refinancing worth it?
Rule of thumb: when the rate drop saves more per month than the closing costs divided by the months you expect to keep the loan — i.e. you will stay past the break-even point. A 0.5–1 percentage point drop on a long remaining term usually clears the bar.
Should I reset to a fresh 30-year term?
A fresh term lowers the payment most but can increase lifetime interest. If cash flow allows, ask the new lender for a term matching your remaining years and keep the savings purely from the rate.
中文说明
利率下行时，再融资（转按揭）用一笔低息新贷款置换存量房贷——但需要付出手续费。本计算器并排对比两笔贷款：月供、全周期利息，以及手续费多久能靠月供节省回本。
"同剩余期限口径"两行专门剥离纯利率差的影响：若新贷款同时拉长了期限，月供下降有一部分只是把同一笔债务摊到了更多月份，同期限对比才能看出利率优惠本身的价值。
常见问题
什么情况下转按揭划算？
经验法则：月供节省 × 预计持有月数 > 手续费总成本，即持有时间超过"回本月数"才划算。剩余年限较长时，利率下降 0.5~1 个百分点通常就能越过门槛。
要不要重新按 30 年期限摊还？
重置成完整 30 年期月供最低，但全周期总利息可能不降反升。若现金流允许，建议新贷款期限对齐原贷款剩余年限，让节省完全来自利率优惠本身。