Is a 20% Down Payment Necessary? What Less Costs You
Short answer: a 20% down payment is not always necessary. Many lenders accept 3% to 5%, but you borrow more, pay a higher monthly payment and usually pay mortgage insurance. On a $400,000 home at 6.5%, 20% down gives a payment of about $2,023, 10% down about $2,425 and 5% down about $2,655 including an assumed insurance cost. Waiting to reach 20% has its own costs in rent and missed price growth.
Key takeaways
- Twenty percent avoids private mortgage insurance on a conventional loan and gives the lowest payment, but it is not a requirement.
- Putting down 5% instead of 20% on $400,000 adds about $632 a month in this example and about $60,000 more borrowed.
- Waiting costs money too: rent paid while you save, and price growth you miss.
- The right choice depends on your savings, your market and how much cushion you keep after buying.
What does each deposit cost per month?
The table is for a $400,000 home on a 30-year loan at 6.5%. The insurance figure is an assumption (about 0.8% of the loan a year at 5% down, 0.5% at 10% down, none at 20%), since real quotes depend on your credit and lender.
| Deposit | Loan | Principal and interest | Assumed insurance | Total a month |
|---|---|---|---|---|
| 5% ($20,000) | $380,000 | $2,402 | $253 | $2,655 |
| 10% ($40,000) | $360,000 | $2,275 | $150 | $2,425 |
| 20% ($80,000) | $320,000 | $2,023 | $0 | $2,023 |
Going from 20% to 5% down adds $632 a month, which is $7,584 a year. Mortgage insurance usually ends once you reach about 20% equity, but not always. Government-backed loans have their own rules for insurance, so ask your lender.
What does waiting to save 20% cost?
Compare buying with 10% now against saving the extra $40,000 to reach 20%. At $1,000 a month it takes 40 months, or 3.3 years, before interest. Over that time:
| Cost of waiting | Amount over 40 months |
|---|---|
| Rent paid at $2,300 a month | $92,000 |
| Price growth missed at 3% a year on $400,000 | about $41,419 |
| Cost of buying now with 10% down | Amount over 40 months |
|---|---|
| Extra payment versus 20% down ($2,425 − $2,023 = $402 a month) | $16,080 |
Rent is not wasted money, since it pays for shelter, and owners have tax, insurance and upkeep that renters do not, so these are not like-for-like. The point is that waiting has real costs that a rule such as "always save 20%" ignores. If prices are flat or falling, or your job is uncertain, waiting costs less and keeps you flexible. See the rent vs buy comparison for a full total.
When does a smaller deposit make sense?
- You would still hold a healthy emergency fund after the deposit and closing costs.
- The payment, including insurance, fits your budget with a stress test. See can I afford to buy a house.
- Prices in your area are rising faster than you can save.
- You plan to stay long enough to recover buying costs, at least five to seven years.
When is waiting the better choice?
- The deposit would use your whole emergency fund.
- The payment with insurance is a stretch.
- Your income or plans are uncertain, such as a likely move in the next few years.
- You carry high-interest debt that costs more than the home's growth. See the debt payoff plan.
Plan the savings in how long it takes to save a down payment, and check programmes for first-time buyers, which may lower the deposit you need.
What mistakes surround the 20% rule?
The rule is a useful default, but it can steer people into waiting when buying sooner would have cost less, or into stretching when waiting would have been wiser.
- Draining your emergency fund to reach 20%, which leaves no cushion after buying.
- Assuming mortgage insurance never ends. On many loans it can be removed once you reach enough equity.
- Comparing only the monthly payment and ignoring total interest over the loan.
- Forgetting that first-time buyer programmes may reduce the deposit you need.
- Waiting for a perfect number while rent and prices keep moving.
How do you put this into practice?
To decide, list three numbers: the monthly payment at each deposit you are considering, the cash you would have left after closing, and how long you plan to stay. If the payment fits with a margin, the cushion is healthy and you will stay five years or more, a smaller deposit can be reasonable. If any of the three is weak, waiting or choosing a cheaper home is usually the safer route. Keep a short note of the assumptions you used, such as the rate, the tax and insurance figures and the deposit, so that when something changes you can update one number and see the effect at once. A plan you can rerun in five minutes gets used, and a plan that lives in your head does not.
Sources and further reading: the Consumer Financial Protection Bureau explains down payments, mortgage insurance and closing costs.
General education, not financial advice. Reviewed October 2026. Insurance costs, rent and price growth are assumptions for illustration. Loan programmes and insurance rules differ by lender and country.
Frequently asked questions
Is a 20% down payment always necessary?
No. Many lenders accept 3% to 5% on some loans. A smaller deposit means a bigger loan, a higher payment and usually mortgage insurance, so check the total cost.
How much does a smaller down payment cost per month?
On a $400,000 home at 6.5%, the payment including assumed insurance is about $2,655 at 5% down, $2,425 at 10% and $2,023 at 20%. So 5% down adds about $632 a month.
What is mortgage insurance?
A cost added when the deposit is small, to protect the lender. On conventional loans it usually ends once you reach about 20% equity. Government-backed loans have their own rules.
What does it cost to wait and save 20%?
Rent paid in the meantime and any price growth you miss. In the example, 40 months of waiting means $92,000 of rent and about $41,419 of price growth on a $400,000 home.
Does a smaller down payment mean a worse deal?
Not always. If prices are rising faster than you can save, buying sooner can cost less than waiting. It depends on your market, your cushion and how long you plan to stay.