Retirement Calculator
Project your retirement nest egg from current savings, monthly contributions and expected return — see how much is growth versus what you put in.
Enter your age now, the age you plan to retire, what you’ve saved so far, what you add each month, and the annual return you expect. You get the projected nest egg at retirement — and how much of it is growth versus what you put in.填入你现在的年龄、计划退休的年龄、目前已存的金额、每月新增的金额，以及你预期的年化收益率，即可得到退休时的预计资产总额——以及其中有多少来自增值、多少来自本金投入。
Fill in all five fields to project your nest egg.填入五个字段即可预测你的退休资产。
- Total contributed累计投入
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- Investment growth投资增值
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- Years to retirement距退休年数
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- Growth share增值占比
Your nest egg is what your current savings grow into, plus what a stream of monthly contributions grows into, both compounded at your expected return until retirement. Two simple pieces — a lump sum and a monthly annuity — added together. The longer the runway and the higher the return, the more of the final number is growth rather than the cash you actually set aside.你的退休资产由两部分构成：当前储蓄按预期收益率复利增长的结果，加上每月投入这条现金流复利增长的结果，两者一直复利到退休。就是这么简单——一笔本金加上一份按月年金相加。时间越长、收益率越高，最终数字中来自增值的部分就越大，而非你实际存入的现金。
01The formula公式
Monthly rate i = Annual% ÷ 100 ÷ 12月利率 i = 年化% ÷ 100 ÷ 12
Nest egg = P·(1+i)m + c·((1+i)m − 1) ÷ i退休资产 = P·(1+i)m + c·((1+i)m − 1) ÷ i
(when i = 0: Nest egg = P + c·m)（当 i = 0 时：退休资产 = P + c·m）
P is your current savings, c the monthly contribution, m the number of months, and i the monthly return. The first term compounds the money you already have; the second is a standard future-value-of-an-annuity, treating each contribution as arriving at month-end (an ordinary annuity). Total contributed is simply P + c·m; everything above that is growth.P 是当前储蓄，c 是每月投入，m 是月数，i 是月收益率。第一项让你已有的钱复利增长；第二项是标准的年金终值，假设每笔投入在月末到账（普通年金）。累计投入就是 P + c·m；超出这一部分的都是增值。
02A worked example一个算例
Suppose a saver is 30 today and plans to retire at 65. They hold $50,000 now, add $500 a month, and assume a 7% annual return.假设一位储户现在 30 岁，计划 65 岁退休。目前持有 $50,000，每月新增 $500，并假设年化收益 7%。
- Months = (65 − 30) × 12 = 420; monthly rate i = 7 ÷ 100 ÷ 12 ≈ 0.005833月数 = (65 − 30) × 12 = 420；月利率 i = 7 ÷ 100 ÷ 12 ≈ 0.005833
- Lump sum grows to 50,000 × (1.005833)420 ≈ $575,000本金增长至 50,000 × (1.005833)420 ≈ $575,000
- Contributions grow to 500 × ((1.005833)420 − 1) ÷ 0.005833 ≈ $901,000投入增长至 500 × ((1.005833)420 − 1) ÷ 0.005833 ≈ $901,000
- Nest egg ≈ $1,476,000. Total contributed = 50,000 + 500 × 420 = $260,000, so growth is ≈ $1,216,000 — over four-fifths of the total.退休资产 ≈ $1,476,000。累计投入 = 50,000 + 500 × 420 = $260,000，因此增值约为 $1,216,000——占总额五分之四以上。
The saver set aside $260,000 over 35 years, yet nearly $1.5 million shows up at the end. That gap is compounding doing the heavy lifting — and it only opens up because the runway is long. Shorten it and the growth share collapses fast.这位储户在 35 年里存入 $260,000，最终却出现近 150 万。这个差距正是复利在发力——而它之所以能拉开，全靠时间够长。缩短时间，增值占比会迅速崩塌。
03The common trap常见陷阱
A projected $1.5 million in 35 years is not $1.5 million of spending power today. At 3% inflation, prices roughly double every 24 years, so that future sum might buy what about $530,000 buys now. This tool projects nominal dollars — the headline figure before inflation. To think in today’s money, either lower the expected return by your inflation assumption, or mentally discount the result. The nest egg is real; its purchasing power is smaller than it looks.35 年后的 $150 万 并不等于今天 $150 万的购买力。若通胀率为 3%，物价大约每 24 年翻一倍，因此那笔未来金额的购买力可能仅相当于今天的 $53 万 左右。本工具计算的是名义金额——即未计通胀的表面数字。要以今天的钱来衡量，可将预期收益率减去你的通胀假设，或在心里对结果打个折扣。资产是真实的，但购买力比看上去要小。
04Where this breaks它的局限
This projection is a clean straight line through a messy world. It assumes a single, steady return every month for decades — reality does not cooperate. A few honest limits:这个预测是一条穿越混乱世界的干净直线。它假设几十年里每个月都有单一、稳定的收益——而现实并不配合。几点诚实的局限：
- Returns are not smooth. Markets deliver their average through wild swings, not a fixed monthly rate. The order of good and bad years — sequence risk — changes the outcome, especially near retirement when the balance is largest.收益并不平滑。市场是通过剧烈波动来实现其平均值的，而非固定的月收益率。好年份和坏年份的顺序——即序列风险——会改变结果，在临近退休、余额最大时尤其如此。
- The return you type is a guess. A 7% assumption is common for a stock-heavy mix, but it is not a promise. Try a lower and a higher rate to see how wide the range of outcomes really is.你填的收益率只是一个猜测。7% 对偏股型组合是常见假设，但绝非承诺。试着用一个更低和一个更高的收益率，看看结果的区间到底有多宽。
- No taxes, fees, or contribution changes. Account fees, taxes on gains, and a contribution that rises with your income are all left out. It also assumes you never touch the money early.未计税费与投入变化。账户费用、收益税，以及随收入增长而提高的投入，都未纳入计算。它还假设你从不提前动用这笔钱。
Time on the runway matters more than the size of any single contribution. Starting earlier beats saving harder later — because the growth compounds on itself.时间的长短，比任何单笔投入的大小都更重要。早点开始，胜过日后拼命多存——因为增值会在自身之上不断复利。
See how the growth curve accelerates in the 在 compounding calculator复利计算器, or check the return an investment earned with the 中看增长曲线如何加速，或用 CAGR calculator年化收益率计算器. 计算某笔投资已实现的年化收益。