Rent Limit vs Monthly Income — Where the 30% Rule Breaks Down

"Rent should be under 30% of your monthly income." It is the advice heard most often when preparing to move out. It is not wrong, but if you apply it as-is, most people end up over the limit. Because rent is not the only cost that has to fit inside that 30%.

Where the 30% rule comes from

It is a rule of thumb: when housing costs exceed 30% of take-home income, spending on food, savings and health tends to get squeezed. The key word is take-home. Calculated on gross salary, the real burden is far larger. The starting point is the net pay figure on your payslip, not the annual contract.

The gap — rent is only part of housing cost

Monthly housing cost is all of the following added together.

• Rent, or the interest on a jeonse loan
• Management fee
• Electricity, gas, water, internet
• One-twelfth of annual costs such as cleaning and repairs at move-out

Deposit loan interest especially must be included: it lowers the monthly rent but replaces it with an interest bill. A 450,000 won rent and 450,000 won of jeonse interest cost the same out of the bank account, yet many people exclude the interest because "that is interest, not rent."

Three steps

1. Confirm net pay — use the after-tax amount on your payslip.
2. Estimate fixed housing costs other than rent — for a studio, management fee and utilities run 120,000–180,000 won a month; for an officetel or apartment, 200,000 won or more.
3. Limit = net pay × 0.3 − fixed housing costs

Table by pay bracket

Monthly net pay	Housing limit (30%)	Rent limit after 150,000 won fees	...plus 200,000 won loan interest
2.2 million won	660,000 won	510,000 won	310,000 won
2.5 million won	750,000 won	600,000 won	400,000 won
3.0 million won	900,000 won	750,000 won	550,000 won
3.5 million won	1,050,000 won	900,000 won	700,000 won
4.0 million won	1,200,000 won	1,050,000 won	850,000 won

Worked example

Net pay 2.8 million won, management fee 150,000 won, electricity, gas and internet 100,000 won.

• Housing limit = 2.8 million × 0.3 = 840,000 won
• Fixed housing costs = 150,000 + 100,000 = 250,000 won
• Rent limit = 840,000 − 250,000 = 590,000 won

A 550,000 won room listed on a property site fits inside the limit. But add 120,000 won of deposit loan interest and real housing cost becomes 820,000 won, almost the full 840,000 won limit. Divide one-off costs like moving fees and household purchases across twelve months and the limit drops further.

Is going over 30% wrong?

Not necessarily. Two cases can justify it.

• A large cut in commuting time — priced as money, it may not be a loss. See the hybrid work calculator post for the method.
• A confirmed income increase — only count what a contract already fixes, such as an end to a probation period or an approved promotion. "Expected to rise" does not go in the calculation.

Conversely, 30% can still feel tight. If your income is irregular, as a freelancer or on a fixed-term contract, aim for 25% or below. The more volatile the income, the earlier housing cost should be adjusted.

Verify with records

Track actual housing costs for the three months after moving. The first month bunches up moving and household purchases, so the figures look off. Use the three-month average as the basis:

• Below 85% of the limit — keep it
• Above 95% — recalculate the limit at the next move

Thirty percent is a starting point. The real answer lives in knowing what you actually spent on housing last month.