Down payment calculator
On a 400,000 home with 20% down, you bring 80,000 in cash and finance the other 320,000. Enter the price and the down payment percentage to see both amounts before you talk to a lender. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Price
- 400,000
- Percent
- 20
- Down payment
- 80,000
- Financed
- 320,000
A down payment is the cash a buyer must bring to closing so the mortgage only covers the rest of the purchase price. Agents quote twenty percent conventional, three and a half percent FHA, or zero percent VA, but every quote is the same product: home price times the chosen percentage, divided by one hundred. This down payment calculator returns that cash figure from two inputs—price and percent—and rejects a percentage outside zero to one hundred instead of inventing a loan that lenders would never originate.
What a down payment is and how the cash figure is computed
A down payment is the cash a homebuyer posts at closing so the lender finances only the remainder of the purchase price. Treat the percentage as a fraction of one, then multiply. A worked conventional example: four hundred thousand at twenty percent is eighty thousand cash, leaving a financed remainder of three hundred twenty thousand.
A worked FHA example: four hundred twenty-five thousand at three and a half percent is fourteen thousand eight hundred seventy-five. Zero percent is a valid all-financed case that returns a down payment of zero and a financed amount equal to the price. One hundred percent is a valid all-cash case that returns a down payment equal to the price and a financed amount of zero.
When the percentage sits outside zero through one hundred the product would describe a negative cash contribution or a down payment larger than the house itself, which is not a well-posed down payment, so the capability fails instead of returning a hollow figure.
Where a down payment calculator earns its keep
Affordability tools and pre-approval checklists already store a target loan-to-value; posting the list price with one minus that LTV as percent fills a card that shows down payment and financed remainder so a shopper can see whether twenty percent of this house is realistic before they ask a lender for private-mortgage-insurance quotes. First-time-buyer explainers that compare FHA three and a half percent against conventional twenty can seed two calls with the same price and different percents and print both cash figures side by side.
Educators teaching loan-to-value can show that a twenty percent down payment is an eighty percent LTV, and can demonstrate the hard fail when someone types one hundred and one percent or a negative rate. Failed validation does not consume balance. Keep price non-negative, keep percent from zero through one hundred, pin the rounded money fields in tests, and you get reproducible down payment cash for widgets, CMS embeds, and edge workers without standing up a mortgage-origination stack of your own.
What you can do with it
Listing and realtor landing pages
Turn a published list price and a quoted down-payment percent into the cash a buyer must bring, with the financed remainder shown beside it.
FHA versus conventional cash comparison
Run the same home price at three and a half percent and at twenty percent to print both cash figures before a first-time buyer picks a program.
Affordability and pre-approval worksheets
Store a target percent next to each house under review and fill a card with down payment and financed amount for the next lender conversation.
FAQ
How is the down payment amount calculated?
Multiply the home purchase price by the down payment percent and divide by one hundred. The result is the cash due at closing for that percent, rounded half-up to two decimals. The financed remainder is price minus that cash.
What happens if the percentage is outside 0 to 100?
A down payment percent below zero or above one hundred is not accepted. Failed validation is not billed.
Can I enter 0% or 100%?
Yes. Zero percent is an all-financed purchase (down payment zero, financed equals price). One hundred percent is all cash (down payment equals price, financed zero).
Does this include closing costs or earnest money?
No. The calculator returns the raw down payment from price and percent.
How do I turn a loan-to-value ratio into a down payment?
Enter one hundred minus the loan-to-value as the down payment percentage. A twenty percent down payment is the same as an eighty percent loan-to-value, so both describe the same cash at closing.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/fin/down-payment \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"price":400000,"percent":20}'const res = await fetch("https://api.kit.forhosting.com/fin/down-payment", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"price": 400000,
"percent": 20
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/fin/down-payment",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"price": 400000,
"percent": 20
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/fin/down-payment", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"price":400000,"percent":20}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"price":400000,"percent":20}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/fin/down-payment", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"price": 400000,
"percent": 20
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "fin.down_payment",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
What a down payment is and how the cash figure is computed
Every loan program, from conventional twenty percent through FHA three and a half percent, VA zero percent, USDA, and jumbo overlays that want twenty-five or thirty, is the same product: down_payment equals price times percent divided by one hundred. Money results are rounded half-up to two decimal places so widgets, spreadsheets, and API clients agree on the last cent when a list price is not a round thousand. This endpoint does not look up mortgage-insurance thresholds, does not apply lender overlays, and does not guess a program from the percent you typed; it applies one deterministic multiply to the two numbers you already have. Closing costs, earnest money already on deposit, prepaid taxes, and seller credits are out of scope: subtract or add those on your own after you have the raw down payment.
Input contract, response shape, and error behaviour
Pair the result with your own closing-cost worksheet if you need cash to close rather than the down payment alone; start here when the product question is a transparent two-input cash figure for a page, a worksheet, or a batch of list-price scenarios you already stored. POST a JSON body with two required finite numbers: price (the home purchase price in currency units, greater than or equal to zero; aliases home_price, house_price, purchase_price, amount) and percent (the down payment as a percent such as twenty for twenty percent, inclusive of zero and one hundred; aliases down_payment_percent, down_percent, percentage, rate). Each field may arrive as a JSON number or as a numeric string. Missing fields, empty strings, and non-finite values fail with invalid_input naming the field and are not billed. On success the body echoes price and percent; returns down_payment as money rounded half-up to two decimals; returns financed as the remainder of the price after that cash, also rounded half-up to two decimals; and includes a short formula string restating the identity. Example: price four hundred thousand and percent twenty yields down_payment eighty thousand and financed three hundred twenty thousand.
Technical questions
What does the down payment calculator cost?
The browser tool is free. API requests use prepaid balance at $0.002 per successful call; invalid input is not billed.