ForHosting KIT · Finance & money

Rent calculator

With a gross annual income of 60,000 and 30% set aside for housing, you can carry a monthly rent of 1,500. You also see your monthly income and your yearly housing budget. Free in your browser.

Free
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Run — free How it works & API

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Worked example

If you enter

Income: 60,000
Percent: 30

You get

Monthly income: 5,000
Annual housing: 18,000
Rent: 1,500
Precision: 2

Affordable monthly rent is the housing budget implied by gross annual income and the share of that income reserved for rent. Housing counselors, listing sites, and the classic thirty-percent rule all start from the same identity: multiply gross annual pay by the housing percentage, then divide by twelve. This rent calculator performs that conversion and nothing else.

What affordable monthly rent is and how it is computed

Affordable monthly rent answers a forward budget question: given gross annual income and the percentage of that income a household is willing to allocate to housing, what monthly rent can it carry. The identity is rent equals income times percent divided by one hundred, then divided by twelve, where income is gross annual pay before tax and percent is the housing share on a zero-to-one-hundred scale (thirty means thirty percent, the common rule of thumb used by counselors and many listing tools).

Worked example: sixty thousand of gross annual income at thirty percent yields an annual housing budget of eighteen thousand and a monthly rent of one thousand five hundred, because sixty thousand times 0.30 is eighteen thousand and eighteen thousand divided by twelve is one thousand five hundred. The same household at twenty-five percent has monthly rent of one thousand two hundred fifty. Another worked pair: ninety-six thousand at thirty-five percent yields an annual housing budget of thirty-three thousand six hundred and monthly rent of two thousand eight hundred.

Monthly income is the annual figure divided by twelve, returned so a listing can be compared with a monthly paycheck without a second division in the client. This page does not invert an existing rent into a housing-cost ratio, does not amortize a mortgage from principal and rate, and does not apply the investor one-percent rule that compares monthly rent to purchase price. Those are different searches with different landings.

Zero income is a valid run and yields zero rent. A negative income is rejected, because a signed annual figure is not a budget base for this identity. Percent must sit in the closed interval from zero through one hundred: zero means no housing budget, one hundred means the entire gross annual income is reserved for rent.

The calculator does not convert currencies, apply tax, or subtract other debts; it is the housing-share ceiling only.

Where an affordable rent calculator earns its keep

Renters shopping listings need a reproducible monthly ceiling from a stated gross salary and a housing share, not a lender worksheet that assumes a mortgage and not a ratio tool that already knows the rent. Relocating employees and housing counselors apply the thirty-percent rule, a tighter twenty-eight-percent conventional front-end cap, or a custom allocation before anyone tours a unit. Budgeting apps and tenant-screening scripts call the contract to seed an affordability badge from payroll income without storing a listing price.

A publisher ranking for rent calculator or affordable monthly rent is targeting people who have a gross annual figure and a percent in mind and want the monthly amount — not the housing-cost ratio of an existing bill, not a mortgage payment, and not a landlord rent-to-price screen.

Classroom notebooks pin known-good pairs — sixty thousand at thirty percent for a clean one thousand five hundred a month, ninety-six thousand at thirty-five percent for two thousand eight hundred, and a negative-income rejection — so a budgeting library cannot silently treat net pay as gross or skip the divide-by-twelve. Failed validation does not consume balance. Keep requests small, pin the rounded rent field in tests, and you get stable affordability arithmetic for widgets, counseling tools, and edge workers without standing up an underwriting suite of your own.

What you can do with it

Apply the 30 percent rule to a salary

Enter gross annual income and percent 30 to see the monthly rent ceiling, monthly income, and annual housing budget the classic rule implies.

Compare listings against a custom housing share

Pass 28, 31, or another allocation to test a tighter or looser cap before touring a unit or signing a lease.

Seed an affordability badge from payroll income

Call the contract from a screening or budgeting script so the displayed monthly rent is derived from income and policy percent, not typed by hand.

FAQ

How is affordable monthly rent calculated?

Send income (gross annual) and percent (0–100 housing share). Rent is income times percent over 100, divided by 12. Example: 60,000 at 30 percent is 1,500 a month.

What percent should I use?

Thirty is the common rule of thumb. Housing counselors also use 28 or 31 as front-end style caps.

What happens if income is negative?

A negative annual figure is not a budget base for this identity, and the failure is not billed.

Is this the same as the housing cost ratio?

No. This page turns income and a housing percent into a monthly rent ceiling. A housing-cost ratio divides an existing rent or PITI by income. Inverse question, different landing.

Does it subtract taxes or my other debts?

No. Income is gross annual pay before tax, and the calculator does not subtract loans, card payments or other debts, nor convert currencies. The result is only the housing-share ceiling on your gross income.

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

POSThttps://api.kit.forhosting.com/fin/rent

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/rent \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"income":60000,"percent":30}'

const res = await fetch("https://api.kit.forhosting.com/fin/rent", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "income": 60000,
    "percent": 30
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/fin/rent",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "income": 60000,
    "percent": 30
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/fin/rent", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"income":60000,"percent":30}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"income":60000,"percent":30}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/fin/rent", 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": 60000,
  "percent": 30
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "fin.rent",
  "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

Per request$0.002

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

It accepts a finite gross annual income and a housing allocation percent, returns the monthly rent amount together with implied monthly income and the annual housing budget, and fails with invalid_input when income is negative instead of emitting a signed rent. Successful API calls are billed at $0.002; invalid input is not charged.

Input contract, response shape, and validation

Example: income sixty thousand and percent thirty yields monthly income five thousand, annual housing eighteen thousand, and rent one thousand five hundred. POST a JSON body with two required finite numbers. income is gross annual income in currency units and must be greater than or equal to zero; a negative income fails with invalid_input naming the field. Aliases gross_annual_income, annual_income, gross, and salary are accepted so a payroll export does not need a rename step. percent is the share of that income allocated to housing, on a zero-to-one-hundred scale: thirty means thirty percent, not 0.30. Aliases housing_percent, allocation, share, and housing_share map to the same field. Optional precision (aliases decimals, dp) is an integer from 0 to 15 that sets decimal places on numeric outputs and defaults to 2, the usual currency display. 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 negative income, a negative percent, a percent above one hundred, 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 percent, returns monthly_income as income divided by twelve, annual_housing as income times percent over one hundred, rent as that annual housing budget divided by twelve (the primary monthly amount), a formula string set to rent = income * (percent / 100) / 12, 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.

Technical questions

What does the rent calculator cost?

The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.

Read the full KIT documentation →

Run — free