Before the bank approves your mortgage, the most important question you should ask yourself is: what share of my income can safely go to the monthly payment? Some people carry a 70% housing burden and think they are fine; others panic at 30%. The industry has a mature set of red lines — the 28/36 rule. Today we break it down so you know your real monthly-payment ceiling.
What Is the 28/36 Rule: Two Red Lines Explained
The 28/36 rule is a debt-health standard used by banks and financial planners. It sets two lines: the 28% line — housing costs (including your mortgage) should not exceed 28% of monthly income; the 36% line — all debt payments (mortgage + car loan + credit cards) combined should not exceed 36% of monthly income.
A concrete example: Xiao Yang earns 20,000 a month after tax. On the 28% line, his housing ceiling is 20,000 × 28% = 5,600 yuan. If he also has a 1,500-yuan car loan, then on the 36% line his mortgage can be at most 20,000 × 36% − 1,500 = 7,200 − 1,500 = 5,700 yuan. Taking the stricter of the two, his reasonable housing payment is around 5,600 yuan.
The logic behind the rule is to leave breathing room: 28% of income goes to housing and the remaining 72% covers living costs, savings, and emergencies. Beyond 36%, the debt structure is unbalanced — if you lose your job or rates rise, cash flow breaks quickly. Use our percentage calculator any time to compute your own monthly-payment ceiling from your income.
| Monthly Income (after tax) | 28% Housing Cap | 36% Total Debt Cap | Left for Living |
|---|---|---|---|
| 10,000 | 2,800 | 3,600 | about 6,400 |
| 15,000 | 4,200 | 5,400 | about 9,600 |
| 20,000 | 5,600 | 7,200 | about 12,800 |
| 30,000 | 8,400 | 10,800 | about 19,200 |
| 50,000 | 14,000 | 18,000 | about 32,000 |
Note that the 28% "monthly payment" usually means all housing costs — not just the mortgage, but also property management fees, property taxes, and insurance. Most Chinese cities have no property tax, but property fees, maintenance funds, and decoration installments are all "housing-related" and should be counted, not just the mortgage number.
Use the 28/36 Rule to Reverse-Engineer Your Loan Size
Once you know your monthly-payment cap, work backward to the loan and home price you can handle. Assume income of 20,000 and a housing cap of 5,600. On a 30-year loan at 3.5%, enter a 5,600 monthly payment, 30 years, and 3.5% into our mortgage calculator — it reverses to a loan of about 1.25 million. Add a 30% down payment, and the affordable total price is about 1.78 million.
This step is crucial: set the monthly-payment red line first, then derive the home price — do not fall in love with a property first and then force the down payment and monthly payment to fit. Many people overbuy precisely because they did it backwards — seduced by the show flat and the sales pitch, ending up with a payment above 50% of income and a cliff-dive in quality of life.
Two variables dramatically change how much you can borrow: the down-payment ratio and the loan term. Raising the down payment from 30% to 50% cuts the loan and eases the monthly burden; shortening the term from 30 to 20 years raises the payment but slashes total interest. Use our loan calculator to adjust down payment, term, and rate together until you find the combination where the payment sits inside the red line and total interest is acceptable — that is your "optimal solution."
Adapting the Rule to Real-World Buying
The 28/36 rule comes from the US, and applying it directly to Chinese mortgages needs adjustment. The core difference: first-tier Chinese cities have high prices and high down-payment ratios, and many households live with housing costs at 40%-50% of income as the norm. Sticking to a strict 28% line, many people could never buy. A more practical tiered approach:
Below 30%: safe zone. Housing at or under 30% of income barely affects quality of life, keeps savings flowing, and gives ample buffer against rate rises or income dips.
30%-50%: caution zone. This is the realistic zone for most Chinese first-time buyers. Workable, but only with stable income, an emergency reserve of 6 months of payments, and no other large debts stacked on top. Above 40%, consider cutting other debt or extending the term.
Above 50%: high-risk zone. Housing eats more than half your income, and the rest must cover food, children, and medical costs — leaving almost no room to save. Unless parents are supporting you or income is expected to jump, strongly reconsider your price target.
To judge which zone you are in, use after-tax monthly income as the denominator. Confirm your take-home pay with our salary calculator, then compare against the tiers above to assess your risk level — do not let "everyone else can afford it" drive your decision.
FAQ
Q1: Is the 28/36 "income" pre-tax or after-tax?
After-tax take-home. Mortgage payments are funded from after-tax cash flow; using pre-tax income overstates capacity. If income is volatile (large bonus component), use the average take-home over the past 6-12 months as the denominator.
Q2: Is buying at 60% of income really impossible?
Not impossible, but very risky. A high payment means zero savings and low resilience; one layoff or family emergency and you risk defaulting. If you must buy, meet three preconditions: the down payment is fully secured, you have 6-12 months of payments in cash buffer, and household income growth is highly certain.
Q3: How much do provident-fund loans reduce the burden?
Provident-fund (housing fund) rates are usually 1-1.5 percentage points below commercial rates. On a 1-million loan over 30 years, the monthly payment drops by 500-800 yuan, with meaningful long-term interest savings. Use the provident fund whenever possible and keep the savings for living costs.
Q4: Besides the payment-to-income ratio, what else should I track?
The total debt-to-income ratio (the 36% line), the debt-to-asset ratio (total debt ÷ total assets, ideally below 50%), and the savings rate (monthly savings ÷ income, ideally above 20%). The payment-to-income ratio only measures housing; look at all three for a complete picture.
Q5: My income will grow. Can I buy more now?
Some foresight is fine, but do not gamble. The safe approach: use today's income and its red line as the baseline, and reserve future income growth as room to prepay or shorten the term — do not max out the payment now on the assumption of future income. When income does not grow, high leverage is a pressure cooker.