How Perfingo works out your plan's numbers

Change a salary, a goal or an assumption, and the app sends your whole plan to the calculator for a fresh projection. The app never runs the maths itself. It only shows what comes back.

How does one edit become a new projection?

The calculator projects your plan year by year, for each person, from your plan’s start date to age 100. For a couple, it projects both people together.

While a new projection runs, the charts stay on screen. They show the last result dimmed until the new numbers arrive, so you never see an empty screen.

In what order does the calculator work?

The calculator runs the same steps in the same order every time. Most steps use an earlier step’s result. Here is the big picture in six steps.

The full sequence

The full sequence breaks this into more steps. A few of them run twice, which the note after the list explains.

1. Income. Salary, side income, take-home pay and the CPF contributions from full-time employment, projected for every year.
2. Ad hoc income. One-off sums like an inheritance or a gift, added in full to the cash of the year they arrive. They aren’t taxed and aren’t counted as income.
3. Expenses. Everyday living costs, inflated and stepped up on the promotion or job-change cadence you set.
4. Insurance. Every policy’s premiums, payouts and, for investment-linked and endowment policies, cash values.
5. Liabilities. Loan and debt repayment schedules from your inputs.
6. Child expenses. Costs for planned or existing children, by life stage.
7. Temporary expenses. Costs with an end date, like rent or childcare, projected month by month and added to your total expenses while they last.
8. Ad hoc CPF top-ups. MediSave top-ups a self-employed person needs, based on the income just projected.
9. Taxes. Income tax for every year, on the previous year’s total income. The first year is prorated, as the conventions below explain.
10. Housing and CPF. The mortgage schedule and your CPF Ordinary, Special and MediSave balances, projected together. Housing payments draw on CPF, and CPF interest depends on what’s been paid out.
11. Milestone cost. The cost of every one-off and recurring goal, using step 1’s take-home pay.
12. Total cash expenses. Living costs, insurance, liabilities, child costs, temporary expenses, housing’s cash portion, goal spending, CPF cash overflow and taxes, summed into one figure per year.
13. Minimum cash in bank. Your emergency-fund floor plus what you’re pre-saving toward one-off goals.
14. Asset projection. Cash, investments and CPF, projected year by year from everything so far. This is the waterfall in Cash and assets.
15. Insurance cost, recalculated. The calculator only learns that a policy had to be surrendered early for cash after running the asset projection once. This pass corrects for that.
16. Total cash expenses, again. Re-summed with the corrected insurance figures.
17. Asset projection, again. Re-run with the corrected totals, so the final numbers account for any early surrender.
18. Ideal coverage. The death, critical illness and disability cover your plan’s multiples point to, set against what you actually hold.
19. Chart annotations. The age 55, age 65, insurance, liability, family and milestone markers on the pathway chart.

What conventions does the calculator follow?

A handful of conventions hold across every part of the calculator.

• Percentages exist only in the app. Every rate (inflation, expected return, growth) is a plain decimal behind the scenes. Only the percent input field converts it.
• Dates anchor to your plan date, not today’s date. The calculator counts from your plan’s start date as year 0, year 1, year 2, never from today’s calendar date. Replanning re-anchors to a new “now” and re-seeds your starting balances from your actuals.
• Ages are year arithmetic, not birthdays. Any year’s age is simply the plan year minus your birth year.
• The first projection year is a partial year. A July plan date makes year 0 run July to December, six months, and income, expenses and tax are prorated to match. The same “months remaining” logic, keyed off your plan date’s month, applies to income, expenses, tax and investing.
• Tax is paid a year behind, by design. Year 0 carries your first, partial year’s prorated tax. Year 1 is the catch-up: the full-year tax on your first year’s income. From year 2, each year’s outflow taxes the previous year’s income, because tax is only known once the year that earned it is over.

How is my freedom age worked out?

Your freedom age and every goal’s verdict come from the same rule, run by the app on the calculator’s output: the 4% rule. A pot of liquid assets can fund a lifestyle if 4% of it covers a year’s spending. That is the withdrawal rate that has historically outlasted a retirement of several decades.

Your freedom age is the first projected year where (cash + investments) × 4% is at least that year’s living expenses. Two things affect how that’s worked out.

• CPF is left out of the liquid pot. It’s locked until the statutory ages, so it can’t fund early retirement, however large the balance.
• Lasting spending counts, one-off spikes don’t. Expenses include recurring goal spending too, such as the travel, dining and hobbies of your retirement lifestyle. A freedom age that can’t keep up that spending isn’t real freedom. A one-off goal, like a downpayment or a wedding, is a single-year spike, so it’s left out. The rule counts only spending that lasts from a year through the rest of your plan.

Each goal gets a verdict from the same cash projection. On the goal cards, an “On track” badge is the green verdict.

For a couple, the household is free only once the later of the two people is. The freedom age marker on the pathway chart is this same 4% calculation.

How does the welcome wizard set my target?

The welcome wizard shows a retirement target the moment you type a living expense figure, before your plan has ever reached the calculator. It uses the same 4% figure as the dashboard on purpose, so the wizard’s target and the real projection never quietly disagree.

• The target is the 25 times rule. Yearly retirement spending divided by 4% gives the nest egg needed to fund it. This is the same 4% rule, inverted.
• Today’s expense is inflated to your freedom age first. The wizard compounds the monthly figure you type forward, at your inflation rate, to the age you plan to retire. So the target is in the future dollars you’ll actually spend, not today’s.
• Dream extras become recurring goals. Travel, dining and hobbies each become a recurring goal starting at your freedom age, at their own cadence: travel as a yearly pot, dining and hobbies monthly.
• Extra retirement income becomes a side income. If you expect extra income after retiring, it’s modelled as a side income starting at your freedom age.
• The starter expense estimate is a rough 30% savings rule. Before you enter a real number, the wizard estimates monthly expenses from salary. Roughly 20% goes to employee CPF (if you contribute), then about 30% of what’s left goes to savings. The rest is the estimate, deliberately rough and always editable.

Does the plan assume a market return?

No. The calculator has no default market view. Your expected inflation rate and investment returns, before and after your freedom age, are entirely your inputs. The welcome wizard starts you on 6% and 4%, which you can change.

The one guardrail: expected inflation must be between 0 and 20%. Outside that range the calculator rejects it, rather than quietly clamping it.

The calculator does have built-in numbers: CPF contribution rates, tax bands, housing loan limits and more. These fixed values apply whatever you enter. They’re listed in the Assumptions reference.

Where to read more

Each of these articles goes deep on one part of the calculator.

• How the numbers work: this page, the order of operations, conventions and the 4% rule.
• CPF: contributions, interest, the Retirement Account at 55 and CPF LIFE payouts.
• Housing and property: the mortgage schedule, and how a BTO, resale or private purchase is modelled.
• Income and tax: how pay, side income and income tax are projected year by year.
• Insurance and coverage: premiums, payouts, cash values and how ideal coverage is worked out.
• Children and milestones: child costs by life stage, and one-off and recurring goal spending.
• Cash and assets: how money flows in, out, into investments and out again on a shortfall.
• Assumptions reference: every built-in value and default in one place.
• Scope and limitations: the real-world situations your plan doesn’t model yet.