Housing cost ratio calculator
See what share of gross income goes to housing: 1,800 of housing costs on 6,000 of monthly income is 30%, right at the common 30% rule. You also get the most you can spend under your target and a HUD burden label. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Income
- 6,000
- Housing cost
- 1,800
- Housing cost ratio
- 0.3
- Housing cost percent
- 30
- Target ratio
- 0.3
- Target percent
- 30
The housing cost ratio is the share of gross income consumed by total housing costs in the same period — rent or the mortgage payment, plus taxes, insurance, HOA dues, and any utilities counted as housing. Lenders, housing counselors, and households use that fraction to test the common thirty-percent rule and the related front-end ratio that underwriters apply to mortgage files. This housing cost ratio calculator divides housing cost by gross income, compares the result to a target ratio (default 0.30), and reports whether the household stays at or under the cap. It also classifies the burden with the standard HUD cut-offs: at most thirty percent is treated as affordable, above thirty and at most fifty percent as cost-burdened, and above fifty percent as severely cost-burdened.
What the housing cost ratio measures and how it is computed
The housing cost ratio, also called the housing-to-income ratio or the front-end housing ratio, answers a household-budget question: of every unit of gross income earned in a period, how much is already committed to keeping a roof overhead. Total housing cost is the sum the household actually pays for shelter: rent, or the mortgage principal-and-interest payment, plus property tax, homeowners or renters insurance, association dues, and any utilities the analyst treats as housing rather than as a separate living expense.
Gross income is pay before tax and other payroll deductions, because published affordability rules and most underwriting worksheets are written against that pre-tax base. A household with 6,000 of gross monthly income and 1,800 of total housing cost has a ratio of 0.30 and a housing-cost percent of 30. The same household with 2,400 of housing cost has a ratio of 0.40.
The conventional thirty-percent rule, used by housing counselors and restated in HUD cost-burden language, treats a ratio at or below 0.30 as affordable. HUD further labels a household that spends more than 30 percent of income on housing as cost-burdened, and one that spends more than 50 percent as severely cost-burdened. Those two cut-offs are classification labels on the computed ratio; they do not change the division.
This calculator also compares the ratio to a caller-supplied target (default 0.30) and reports the maximum housing cost that would still pass that target, plus the signed headroom between that cap and the amount actually paid. It does not compute a mortgage payment from principal and rate, a back-end debt-to-income ratio that folds in car loans and credit cards, property tax from an assessed value, or a rent-to-price investment screen such as the one-percent rule.
Where a housing cost ratio calculator earns its keep
Renters deciding whether a listed apartment leaves enough income for food, transit, and savings need a reproducible housing-cost share, not a lender worksheet that assumes a mortgage. First-time buyers and housing counselors test the same identity against a 28 percent conventional front-end cap, a 31 percent FHA-style cap, or the public 30 percent rule before anyone opens an amortization table.
A publisher ranking for housing cost ratio calculator is targeting people who already have a gross-income figure and a total housing bill and want the share, the headroom, and a pass or fail against a stated target — not a mortgage payment, not a full debt-to-income stack, and not a landlord rent-to-price rule.
Classroom and public-policy notebooks pin known-good pairs — 6,000 over 1,800 for a clean 30 percent, a 45 percent cost-burdened case, and a zero-income rejection — so a budgeting library cannot silently swap net pay for gross or treat housing as a residual after other bills. Failed validation does not consume balance.
What you can do with it
Check rent or PITI against the 30 percent rule
Enter monthly gross income and total housing cost to see the housing-cost share, whether it stays at or under 30 percent, and how many dollars of headroom remain.
FAQ
How do I calculate the housing cost ratio?
Example: 1,800 / 6,000 = 0.30, or 30 percent.
What target ratio does the calculator use?
The default target is 0.30, the common 30 percent rule. The passes flag compares the unrounded ratio to that cap.
Is this the same as debt-to-income or the one-percent rule?
No. This page is housing cost over gross income only. A back-end DTI folds in other debts. The one-percent rule compares monthly rent to purchase price for investors. Different questions, different landings.
What counts as housing cost?
Everything you pay for shelter in the period: rent or the mortgage payment, plus property tax, home or renters insurance, association dues and any utilities you treat as housing. Use the same period as the income figure.
What do cost-burdened and severely cost-burdened mean?
They are HUD labels for the ratio. Spending up to 30% of gross income on housing counts as affordable, more than 30% and up to 50% as cost-burdened, and more than 50% as severely cost-burdened.
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/finance/housing-cost-ratio \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"income":6000,"housing_cost":1800}'const res = await fetch("https://api.kit.forhosting.com/finance/housing-cost-ratio", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"income": 6000,
"housing_cost": 1800
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/finance/housing-cost-ratio",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"income": 6000,
"housing_cost": 1800
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/finance/housing-cost-ratio", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"income":6000,"housing_cost":1800}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"income":6000,"housing_cost":1800}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/finance/housing-cost-ratio", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"income": 6000,
"housing_cost": 1800
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "finance.housing_cost_ratio",
"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.
Limits
max_abs | 1000000000000000 |
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
Successful API calls are billed at $0.002; invalid input is not charged.
What the housing cost ratio measures and how it is computed
The identity is housing_cost_ratio equals housing_cost divided by income, where both amounts use the same currency and the same period — monthly against monthly, or annual against annual.
Input contract, response shape, and validation
Zero housing cost is valid and yields a ratio of zero. Values in the interval from just above zero through one are treated as decimals (0.28 is twenty-eight percent). Values greater than one and at most one hundred are treated as percents, so 30 means the same cap as 0.30. POST a JSON body with two required finite numbers in the same currency and period. income is gross household income for the period and must be strictly greater than zero, because the housing-cost ratio divides by that figure; aliases gross_income, gross, and monthly_income are accepted so a payroll export does not need a rename step. housing_cost is total housing cost for the same period and must be greater than or equal to zero; aliases housing, total_housing, and housing_costs are accepted. Optional target_ratio is the affordability cap used for the pass flag and for the affordable-housing-cost line; it defaults to 0.30. Aliases target, ratio_limit, and max_ratio map to target_ratio; target_percent and max_percent are read as already-percent figures and divided by one hundred when target_ratio is omitted. Optional precision (aliases decimals, dp) is an integer from 0 to 15 that sets decimal places on numeric outputs and defaults to 4. Each numeric field may arrive as a JSON number or as a numeric string. Absolute values must stay within one quadrillion so intermediate products remain finite in IEEE double precision on the Worker and in the browser. Missing fields, empty strings, non-finite values, a non-positive income, a negative housing cost, a non-positive target, or a value outside those limits fail with invalid_input naming the field and are not billed. On success the body echoes rounded income and housing_cost, returns housing_cost_ratio and housing_cost_percent, echoes the resolved target_ratio and target_percent, returns affordable_housing_cost as income times the target, headroom as that cap minus actual housing cost, over_budget as the non-negative excess, a boolean passes flag from the unrounded ratio versus the target, a HUD-style status string (affordable, cost_burdened, or severely_cost_burdened), a formula string, and the precision used. Prefer JSON numbers over currency-formatted strings; dollar signs and thousands separators are not parsed. Pricing for a successful item is a flat $0.002.
Where a housing cost ratio calculator earns its keep
Keep requests small, pin housing_cost_ratio and status in tests, and you get stable affordability arithmetic for widgets, counseling tools, and edge workers without standing up a full underwriting suite of your own.
Integration use cases
Screen a file against a lender front-end cap
Pass target_ratio 0.28 or 0.31 (or 28 / 31 as percents) to test a conventional or FHA-style housing ratio before running a full debt-to-income stack.
Label HUD cost burden in counseling tools
Use the status field — affordable, cost_burdened, or severely_cost_burdened — so a counseling or research notebook applies the same 30 and 50 percent cut-offs every time.
Technical questions
What do affordable, cost_burdened, and severely_cost_burdened mean?
Those labels follow HUD cost-burden cut-offs on the computed ratio: at most 30 percent is affordable, above 30 and at most 50 percent is cost-burdened, and above 50 percent is severely cost-burdened. They are independent of a custom target.
What does the housing cost ratio calculator cost?
The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.