Down Payment Calculator

A down payment is a percentage of a price, and everything on this page comes from a single relationship:

$D = V \times p$

• $V$ — the agreed price of the house or vehicle
• $p$ — the down-payment fraction as a decimal ($20\% = 0.20$)
• $D$ — the cash paid up front

What is financed is the remainder:

$L = V - D = V(1 - p)$

The ratio $L/V$ is the loan-to-value, or LTV, and it is simply $1 - p$. A 20% deposit is an 80% LTV.

Know any two of $V$, $p$, $D$ and the third follows:

$p = \frac{D}{V}, \qquad V = \frac{D}{p}$

That last form is the most useful one in practice: it converts the cash you have into the price it covers at a chosen percentage.

How much you should put down is not a maths question. Minimums depend on the lender, the loan programme, the country and the current rules, all of which change. This page computes the arithmetic for whatever percentage you enter.

Time to save a target deposit

With savings $S$ already set aside and $c$ put away each month:

$\text{months} = \frac{Vp - S}{c}$

Always round up — a partial month does not complete the deposit. If the savings themselves earn interest, use the annuity form instead: solve $S(1+i)^N + c\frac{(1+i)^N - 1}{i} = Vp$ for $N$.

Cash needed is more than the deposit

Up-front cash is the deposit plus fees:

$\text{cash to close} = Vp + F$

where $F$ covers closing or registration costs, taxes and prepaid items. Those amounts vary by jurisdiction and provider; enter your own figures.

Vehicles: trade-in and negative equity

A trade-in behaves like extra cash, and a loan still owed on it behaves like negative cash:

$D_{\text{effective}} = \text{cash} + (\text{trade-in value} - \text{loan still owed on it})$

If that bracket is negative, the balance is rolled into the new loan and the amount financed exceeds the vehicle price — LTV above 100%. The formula handles it; the arithmetic just returns a bigger $L$.

• Percent left unconverted: $p = 0.12$, not $12$. A factor-of-100 error here is unmissable once you sanity-check the size of the answer.
• Taking the percentage of the loan instead of the price: $D = V \times p$ uses the price. Applying the percentage to the amount financed gives a circular, wrong figure.
• Reversing $p = D/V$: dividing price by deposit gives a number above 1. The deposit goes on top.
• Confusing the deposit with total cash needed: closing or registration costs sit on top of $D$.
• Assuming a bigger deposit scales the payment proportionally: the payment depends on the financed amount $V(1-p)$, so going from 10% to 20% down cuts the payment by about $1/9$, not by half.
• Treating a trade-in as pure cash: subtract anything still owed on it first, or the effective deposit is overstated.
• Reading a minimum percentage as a rule: minimums differ by lender, programme and country, and they change. Use your own figure.