How long until you have the deposit?
The target is not what a deposit costs today — it is what it will cost when you actually get there, because house prices do not wait for you to save.
What a home like the one you want costs now.
Common ones are 5%, 10% and 20%.
More options(5)
How fast prices where you're looking have been rising. This is what moves the target.
Many people keep a deposit fund in cash rather than markets, since it's needed soon — lower this if that's you.
To save a 10% deposit on a $350,000 house
4 years 10 months
Today's 10% deposit is $35,000, but by the time $500 a month gets there — 4 years 10 months — the house is assumed to cost more, so the deposit needed will have grown to $40,575. A calculator that assumes the price never moves would tell you 4 years 2 months instead, which is $35,000 short of what you will actually be asked for.
- Deposit needed today
- $35,000
- Deposit needed in 4 years 10 months
- $40,575
- Extra from rising prices
- $5,575
How the target moves
The deposit price at 3% house-price growth a year, not today's figure held flat.
| Year | House price | Deposit needed |
|---|---|---|
| Today | $350,000 | $35,000 |
| Year 1 | $360,500 | $36,050 |
| Year 2 | $371,315 | $37,132 |
| Year 4 | $393,928 | $39,393 |
| Year 5 | $405,746 | $40,575 |
If returns average…
Nobody knows which of these happens
| Assumption | Time to the deposit |
|---|---|
| 4% a year — cautious | 5 years 5 months |
| 7% a year — middle | 4 years 10 months |
| 10% a year — optimistic | 4 years 6 months |
Markets do not return the same amount every year. The band shows the same plan under three different assumptions, so you can see how much the answer depends on a number nobody knows.
Why the target has to move
Almost every deposit calculator does the same thing: it takes the price of the house today, multiplies by the deposit percentage, and works out how long that fixed number takes to save. It is the natural way to set the problem up, and it is wrong for anyone saving over more than a year or two, because the number it fixes is the one thing that does not actually stay fixed.
House prices move while a deposit is being built — that is the whole reason "how long will it take" is a harder question than "how much is 10% of the price today". This calculator treats the deposit as a moving target: it grows every year at the house-price growth rate you set, and the savings pot has to catch a number that is getting bigger while it runs, not one standing still.
What that costs you, in time
The gap between the two versions is usually not small. Compounding works on the target exactly as it works on the savings — a deposit growing at 3% a year is roughly a third bigger after ten years than it was on day one, which is ten more years of monthly saving quietly added to nobody's plan but reality's. The calculator above shows both figures side by side: what a calculator that assumes the price never moves would tell you, and what actually has to be saved by the time you get there.
The "how the target moves" table breaks that same growth down year by year, computed the same way the headline figure is — nothing on this page is typed in twice.
The assumptions doing the work
- House price growth is the whole mechanism. Set it to 0% and this calculator behaves exactly like a standard savings-goal tool — the round-trip is covered by a test in the underlying engine. Set it higher than the return on the savings and the pot never catches up at all; the calculator says so rather than pretending an answer exists.
- Assumed return is a separate number on purpose. A deposit due within a few years is usually kept somewhere safe rather than invested, so this is very often a cash savings rate rather than a market return — lower it if that describes your plan.
- Local prices, not a national average. House-price growth varies enormously by area and by property type. The figure that matters is the one for the kind of home you are actually looking at, not a headline national number.
How it relates to the other tools
The savings goal calculator answers the same "how much a month" question for a target that genuinely is fixed — a wedding, a car, a number you have already decided on. This page exists because a house deposit usually is not that: the target is set by a market moving independently of the saving. Once the deposit is in hand, the loan repayment calculator works out what the mortgage on the rest would actually cost.
Common questions
Why not just save more to beat rising prices?
What if house prices actually fall?
Does this account for mortgage rates or loan size?
Not advice. This tool applies arithmetic to assumptions you entered. It does not know your circumstances, your tax position or your goals, and it is not a recommendation to buy, sell or hold anything. Past returns do not predict future ones, and no figure here is a forecast.