How long will it take to save a house down payment?
By GoalLab · Published June 10, 2026 · Updated June 10, 2026
Saving a $60,000 down payment — 20% of a $300,000 home — from zero at a 4% APY takes 68 months (about 5.7 years) depositing $800 a month, or 38 months (about 3.2 years) depositing $1,500 a month.
The benchmark scenario, worked in full
Take a $300,000 home and the classic 20% down payment: a $60,000 target. Run through the GoalLab timeline solver from a $0 start with monthly compounding at an example 4% APY, an $800 monthly deposit crosses the goal in 68 months — about 5.7 years — after $54,400 of deposits and $6,545.34 of earned interest. Raise the deposit to $1,000 and the timeline falls to 55 months (4.6 years, $55,000 deposited, $5,254.57 of interest). At $1,500 a month it takes 38 months — about 3.2 years — on $57,000 of deposits and $3,659.80 of interest.
Two patterns are worth absorbing. First, the timeline responds almost in proportion to the deposit: nearly doubling the monthly amount from $800 to $1,500 cuts the wait from 68 months to 38. Second, the faster saver actually deposits more of the $60,000 personally ($57,000 versus $54,400) — a shorter plan gives compounding less time to work, so speed is bought with cash, not yield.
Why 20% is the reference line — and what smaller targets cost
Twenty percent is the threshold at which conventional mortgages typically stop requiring private mortgage insurance (PMI), a recurring charge that protects the lender rather than you. Lenders accept much smaller down payments, but below 20% on a conventional loan you should generally expect PMI on top of the payment until your equity grows.
Smaller targets shorten the savings phase dramatically. On the same $300,000 home at $800 a month and 4% APY, a 5% down payment ($15,000) takes 19 months and a 10% down payment ($30,000) takes 36 months, versus 68 months for the full 20%. The trade is timing versus carrying cost: getting in years earlier with PMI and a larger loan, or waiting for the cleaner 20% position. The solver prices the waiting side of that trade; a lender quote prices the other.
The deposit is the lever; interest is a tailwind
Re-running the $60,000 plans with the APY at zero shows what the rate actually buys. With no interest, the $800-a-month plan needs 75 months instead of 68 — so compounding at 4% shaves roughly seven months off a nearly six-year plan. The $1,500 plan only drops from 40 months to 38, a two-month saving, because the shorter window leaves interest little room to accumulate.
The asymmetry is the lesson: yield rewards long timelines, and budget rewards every timeline. If you must choose between hunting an extra half point of APY and finding another $100 a month in the budget, the deposit wins at any horizon a down payment realistically spans.
What a head start does to the wait
Existing savings move the finish line forward by more than their face value suggests, because they compound for the whole plan. Starting the $60,000 chase with $10,000 already banked, the $800-a-month saver finishes in 55 months (4.6 years) instead of 68 — thirteen months sooner — while the $1,500-a-month saver finishes in 32 months (2.7 years) instead of 38.
This is why windfalls are disproportionately valuable early in a down-payment campaign: $10,000 added in month one erases more calendar time than $10,000 of deposits spread across the final year, since the early lump sum earns interest the entire way.
The nominal-rate caveat
Every timeline above assumes the APY you enter holds for the whole plan. Real savings rates float with the market — the 4% used here reflects what high-yield savings accounts have recently paid, and it can move down as easily as up. A multi-year plan should be re-solved whenever your bank reprices, and a conservative planner can run the numbers at a lower rate to see the downside timeline.
The target itself can also drift: home prices, closing costs (which come on top of the down payment), and your chosen neighborhood all move over a five-year horizon. The calculator counts whole months — it reports the first month-end at which the balance crosses the goal — and it solves arithmetic from your inputs. It is a planning estimate, not advice on when or whether to buy.
Solving it for your own numbers
The useful version of this article is the one with your inputs. Set the goal to the down payment for a realistic price in your market, enter what you already have saved, put in the deposit your budget honestly supports, and use your account's actual APY. If the resulting timeline is unacceptable, the levers appear in order of power: a bigger monthly deposit, a lump-sum head start, a smaller down-payment percentage (priced against PMI), and finally the rate.
Questions
- Do I really need 20% down to buy a house?
- No. Conventional loans commonly close with far less, but below 20% you should generally expect private mortgage insurance on top of the mortgage payment. On a $300,000 home at $800 a month, saving 5% ($15,000) takes 19 months versus 68 months for the full 20% ($60,000) at 4% APY.
- How much faster is $1,500 a month than $800?
- For a $60,000 goal at 4% APY from zero, $1,500 a month finishes in 38 months versus 68 months at $800 — thirty months, or two and a half years, sooner.
- How much does interest contribute while saving?
- On the $800-a-month plan, $6,545.34 of the $60,000 arrives as interest and the 4% APY trims about seven months versus saving with no yield. On the faster $1,500 plan interest adds $3,659.80 and saves only two months — shorter plans lean almost entirely on deposits.
- What if I already have $10,000 saved?
- A $10,000 head start cuts the $800-a-month timeline from 68 to 55 months and the $1,500-a-month timeline from 38 to 32 months at 4% APY, because the lump sum compounds for the entire plan.