Scope for international readers: This calculator is designed for current household retirement and budgeting scenarios in mainland China. Its inputs and conventions are not adapted to every country’s or region’s pension system, taxes, currency or household expenses, so it may not be suitable elsewhere. The underlying logic of mapping income, expenses and assets over time can still serve as a reference, but applying it elsewhere requires locally appropriate assumptions. The English translation does not make the calculator globally applicable.
Once retirement becomes something you need to think seriously about, the household accounts need to tell you more than the balance in your bank account.
The year a salary becomes a pension, the year a child starts university, when an annuity begins paying, and whether you still need to replace a car or renovate your home can all change a particular year’s finances. Bundling everything into one number for “how much we need to retire” makes it easy to miss the timing.
I built a small website called the Simon Family Retirement Cash Flow Calculator. I would like to recommend it to anyone working through these questions.
Open the Family Retirement Cash Flow Calculator
It lays out a household’s future income, expenses and investable asset balance year by year. Change an input, and the chart and annual breakdown update with it.
Start with one task: put your household’s income and expenses on the same timeline, and identify the years that deserve closer attention. Every result depends on the assumptions you enter.
01. Put the Family Timeline Together First
Many couples do not retire in the same year. One partner starts receiving a pension while the other still earns a salary. A few years later, both have retired, and household income changes again.
Children’s expenses follow their own timeline. Budgets differ across primary school, secondary school, university, and further study or a transition period. Once a child reaches the independence age you specify, the model stops including that child’s expenses.
The calculator lets you enter each partner’s retirement year and the year an insurance annuity begins paying, and add children individually. Each child can have a birth year, an independence age and budgets for different stages. Two children of different ages do not have to share one expense estimate. Single-person households can also use it: enter 0 for the other partner’s age.
This gives each turning point in the accounts a specific explanation. A salary may have become a pension, a child may have become financially independent, or a major expense may fall in that year.
02. Enter Income, Assets and Expenses Separately
The current version groups its inputs as follows:
| Input group | What you can enter |
|---|---|
| Household income | Each partner’s monthly take-home salary, monthly pension after retirement, and monthly commercial insurance annuity |
| Investable assets and returns | Initial financial assets, dividend-paying principal, expected dividend yield, and annual return applied to the investable asset balance |
| Children’s expenses | Monthly budgets from infancy through further study or a transition period, with individual overrides |
| Recurring expenses | Food, housing and utilities, transport, healthcare and insurance premiums, leisure, travel and miscellaneous spending |
| Major one-off expenses | The year and household out-of-pocket cost of items such as replacing a car or renovating a home; ranges can also be entered |
You do not have to start with every receipt. Use the major expenses and monthly budgets you can reasonably establish, make a first estimate, then refine it.
Listing major expenses separately is particularly useful. A renovation can absorb several years of savings. Averaging it into everyday spending can make it harder to see the year when you actually need the cash.
03. I Suggest Looking at the Turning Points
The page shows the first year’s monthly net surplus, the first year with a funding shortfall, the final investable asset balance, and a chart of annual balances. Below it is a year-by-year table. Click a year to see the components of income and spending.
I suggest starting with a few key points in that table: before and after each partner retires, when a child moves to another stage or becomes independent, when annuity payments begin, and when a major expense occurs.
Here are some years from the website’s built-in fictional example:
| Year | Change in that year | Monthly inflow (CNY) | Monthly recurring expenses (CNY) | Monthly net surplus (CNY) |
|---|---|---|---|---|
| 2026 | Both partners work; the child is in secondary school | 22,750 | 16,000 | 6,750 |
| 2036 | The child reaches the independence age set in the example | 22,750 | 13,000 | 9,750 |
| 2046 | The male partner retires and insurance annuity payments begin | 19,750 | 13,000 | 6,750 |
| 2048 | Both partners are retired | 15,750 | 13,000 | 2,750 |
These figures only illustrate how the tool works. They are not my household’s finances or budget recommendations for anyone else.
Under the same set of inputs, the monthly surplus changes from CNY 6,750 to CNY 9,750, then returns to CNY 6,750 before falling to CNY 2,750. Changes in income and expenses can offset one another or compound. Looking only at a total balance makes those transitions easy to overlook.
If the balance turns negative, go back to that year and examine the expense, income transition or return assumption affecting the result. The tool identifies the year so you can investigate further.
04. A Practical First Run
- Start with the fictional example. Get familiar with the inputs, chart and annual breakdown. Open a few years to see how their income and expenses are composed.
- Replace the example with your own inputs. Begin with income, assets and everyday expenses you can establish, then add retirement, annuity and child-related dates. Pension and annuity amounts need to be checked separately.
- Change one group of assumptions at a time. For example, lower expected dividends, adjust a retirement year or increase the living budget. See which years’ surpluses and balances change most. You can export and save each scenario separately.
- Export the CSV breakdown. Keep a record of the annual results under those inputs. You can revisit it, continue working in a spreadsheet or discuss it with your family.
Sometimes a tool’s value is simply getting two people to discuss the same table. “It should be enough” can become “There is still an expense in this year that we have not included.”
05. Understand These Calculation Conventions
The current version calculates by calendar year. It uses a pension for the whole retirement year and counts annuity payments for the whole year in which they begin. It does not calculate by retirement month or estimate a pension from local social insurance rules.
All amounts are nominal Chinese yuan. The model does not automatically include inflation, salary growth, taxes, asset price fluctuations or random simulations. A nominal balance decades from now cannot be treated as having the purchasing power of the same amount today. A curve calculated with a fixed return also cannot represent the order in which actual market returns occur.
Return inputs need care too. Dividend cash flow and the return applied to the investable asset balance are calculated separately. Counting the same dividend in both places will overstate the result. Separate insurance assets are shown independently: they do not compound as part of the investable asset balance and are not automatically reduced as annuity payments are received.
The “first funding shortfall” is the first year with a negative year-end investable asset balance. Negative balances remain visible so you can examine the shortfall, but they do not mean the household has obtained a loan. A non-negative year-end balance also cannot rule out cash shortages within that year.
This is a scenario calculation. It helps examine the relationships between your assumptions. It is not investment, insurance or retirement decision advice, and it does not guarantee future principal, returns or cash flow.
The website’s usage guide provides the formulas and fuller explanations of the limitations. I suggest reading it before entering your first set of inputs. The calculator and its guide currently use Chinese.
06. Data Stays in Your Browser
The current version calculates within the browser. The salary, pension, asset and budget inputs you enter are not submitted to the server. There is no account or login. Parameters are saved in the current browser’s website storage, so you can continue when you return using that browser.
On a shared device, consider who else can use the same browser. You can remove the parameters with the calculator’s “Clear inputs” button (“清空填写”) or the browser’s site-data settings. An exported CSV is a local file; check its household financial information before sharing it.
Visits to the website still pass through the hosting provider. Processing access logs is separate from calculating financial inputs locally. See the data and privacy page for details.
07. Try It with Your Own Assumptions
If you are considering life after retirement or want to organize future household spending, open the calculator and start with the income and expenses you know best.
Use the Simon Family Retirement Cash Flow Calculator
You can report calculation or interface problems through the project repository. Include fictional or anonymized inputs that reproduce the issue. There is no need to publish your actual household accounts.
08. Planned Updates and Feature Requests
I plan to add inflation and other factors affecting long-term calculations in future iterations, extending the scenarios available for household income, expenses and asset balances.
If you would like another calculation factor, or the existing inputs do not cover a household situation you need to model, please reach me through the author’s contact channels or submit a feature request through the project repository. Explain what you want to calculate and the results you would like to see so we can discuss the need clearly.
Please use fictional or anonymized examples when providing parameters. You do not need to share complete personal financial records.
The features and calculation conventions described here reflect the online V1 version and its guide as of October 13, 2026. The additional factors in the update plan have not yet been released.