Uncover the real annualized interest rate (APR / IRR) behind credit card installments, consumer financing, and car loan promotions. Lenders often advertise nominal monthly handling fees (e.g. 0.6%/month) that look harmless, but the true annualized rate is almost double (around 13.5%+) because you repay principal each month while fees are charged on the entire initial sum.
This calculator implements a robust Newton-Raphson internal rate of return (IRR) solver in your browser to give you the honest APR, effective annual rate (EAR), and total financing costs.
Frequently asked questions
Why is true APR roughly twice the advertised fee rate?
When you repay equal principal each month, your average debt balance throughout the term is roughly half of the original loan. Charging fees on the full initial amount throughout the term means you are paying interest on money you have already paid back.
What is the formula for calculating true APR?
It solves for internal rate of return (IRR) where the present value of all future installment cash flows equals the initial borrowed amount.
Is IRR calculation safe and private?
100% private and computed locally in your browser with zero server telemetry.
中文说明
揭秘信用卡账单分期、车贷分期及消费金融背后的真实年化利率（APR / IRR）。许多平台常宣传"月费率仅 0.6%"，让借款人误以为年利率只有 0.6% × 12 = 7.2%。但由于借款人每月都在归还本金，资金实际平均占用额仅为一半左右，导致真实年化利率高达 13.5% 以上！
本计算器基于 Newton-Raphson 牛顿迭代数值算法，在浏览器本地秒级求解内部收益率（IRR），让您看清各种分期的真实融资成本，拒绝低费率消费陷阱。
常见问题
为什么分期的真实利率几乎是宣传费率的两倍？
因为分期每月都在偿还本金，您实际欠银行的钱逐月减少，平均欠款只有借款总额的一半左右；但银行手续费却始终按初始全额本金计算，相当于在为您已经还掉的钱继续支付利息。
国家对贷款明示年化利率有什么规定？
中国人民银行早在 2021 年就要求所有从事贷款业务的机构必须明示贷款年化利率（采用 IRR 内部收益率口径计算），杜绝用"日息万分之五"、"月手续费 0.6%"误导消费者。
计算过程安全保密吗？
完全在您本地浏览器中即时运算，不向任何服务器发送借贷数据，完全保护财务隐私。