House building cost estimator API

Estimate the converted construction area (diện tích xây dựng quy đổi) and the cost of building a house in Vietnam, with every coefficient editable.

GETPOSThttps://apibox.io.vn/v1/vn-build-cost

Data & JSON▶ Try it online

Contractors in Vietnam price houses per square metre of converted area: the floors count 100%, and the foundation, basement, roof, yard and voids are weighted by usual coefficients (strip foundation 50% of the ground floor, pile caps 40%, flat concrete roof 50%, tile roof on trusses 70%, basement 150–250% by depth, yard 50%…). The API builds that table from the plot size, floors, foundation, roof and optional areas, and multiplies it by a unit price.

There is no official coefficient table, so each one is a labelled default you can override with coefficients, and the unit prices are editable presets (shell only, basic, standard, premium turnkey) or your own unit_price. The result splits the cost into the shell and the finishing part and lists what is not included (piling, demolition, permits, furniture).

Use it for a first budget; a contractor’s quote depends on the design, the site and the materials chosen.

Parameters

Name	In	Type	Required	Default
`width, length`	query\|body	number	no		Plot / ground-floor size in metres (or `floor_area`).
`floor_area`	query\|body	number	no		Ground-floor area in m².
`floors`	query\|body	number	no	`1`	Number of floors including the ground floor.
`foundation`	query\|body	string	no	`strip`	`single`, `strip`, `pile`, `raft`.
`roof`	query\|body	string	no	`concrete`	`metal`, `concrete`, `tile_steel`, `tile_concrete`, `none`.
`basement_depth, mezzanine_area, stair_tower_area, terrace_area, balcony_area, yard_area, void_area, upper_floor_area, roof_area`	query\|body	number	no		Optional parts (m², basement depth in m).
`package`	query\|body	string	no	`standard`	Price preset: `rough`, `basic`, `standard`, `premium`.
`unit_price`	query\|body	number	no		Your price per converted m² (overrides the preset).
`coefficients`	body\|query	object	no		Overrides, e.g. {"foundation.pile": 0.5, "roof.metal": 0.25, "yard": 0.7}.

Example

curl "https://apibox.io.vn/v1/vn-build-cost?width=5&length=20&floors=3&foundation=strip&roof=concrete&package=standard" \
  -H "Authorization: Bearer YOUR_API_KEY"

const res = await fetch('https://apibox.io.vn/v1/vn-build-cost?width=5&length=20&floors=3&foundation=strip&roof=concrete&package=standard', {
  method: 'GET',
  headers: {
    Authorization: 'Bearer YOUR_API_KEY',
  },
});
const data = await res.json();
console.log(data);

import requests

res = requests.get(
    "https://apibox.io.vn/v1/vn-build-cost?width=5&length=20&floors=3&foundation=strip&roof=concrete&package=standard",
    headers={"Authorization": "Bearer YOUR_API_KEY"},
    timeout=30,
)
print(res.json())

<?php
$ch = curl_init('https://apibox.io.vn/v1/vn-build-cost?width=5&length=20&floors=3&foundation=strip&roof=concrete&package=standard');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => ['Authorization: Bearer YOUR_API_KEY'],
]);
$response = curl_exec($ch);
print_r(json_decode($response, true));

Response

{
  "footprint_m2": 100,
  "floors": 3,
  "rows": [
    {
      "part": "Foundation",
      "part_vi": "Móng",
      "area_m2": 100,
      "coefficient": 0.5,
      "converted_m2": 50,
      "basis": "Strip foundation (móng băng) 50%"
    },
    {
      "part": "Ground floor",
      "part_vi": "Tầng trệt",
      "area_m2": 100,
      "coefficient": 1,
      "converted_m2": 100,
      "basis": "Each floor, mezzanine, stair tower, balcony 100%"
    },
    {
      "part": "Floor 2",
      "part_vi": "Tầng 2",
      "area_m2": 100,
      "coefficient": 1,
      "converted_m2": 100,
      "basis": "Each floor, mezzanine, stair tower, balcony 100%"
    },
    {
      "part": "Floor 3",
      "part_vi": "Tầng 3",
      "area_m2": 100,
      "coefficient": 1,
      "converted_m2": 100,
      "basis": "Each floor, mezzanine, stair tower, balcony 100%"
    },
    {
      "part": "Roof (concrete)",
      "part_vi": "Mái (concrete)",
      "area_m2": 100,
      "coefficient": 0.5,
      "converted_m2": 50,
      "basis": "Flat concrete roof (mái BTCT) 50%"
    }
  ],
  "converted_area_m2": 400,
  "cost": {
    "package": "standard",
    "package_vi": "Trọn gói khá",
    "unit_price": 6500000,
    "unit_price_source": "preset (editable default, not an official price)",
    "total": 2600000000,
    "rough_part": 1520000000,
    "finishing_part": 1080000000
  },
  "excluded": [
    "piling (ép cọc / khoan nhồi), billed per metre",
    "demolition and soil disposal",
    "permit, design and supervision fees",
    "furniture, air conditioners, appliances",
    "difficult access or night work surcharges"
  ],
  "reviewed": "2026-11-11"
}

Use cases

Give visitors a first budget on a contractor website
Estimate a construction loan in a bank app
Compare quotes from several contractors on the same basis
Plan a house project before hiring an architect

FAQ

Are the coefficients official?

No. They follow common contractor practice, which varies; each coefficient is shown and can be overridden.

Are the unit prices current?

They are editable presets based on 2026 big-city price lists; pass unit_price for your contractor’s price.

Is piling included?

No. Piling is billed per metre of pile; only the pile caps are in the foundation coefficient.

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House building cost estimator API

Parameters

Example

Response

Use cases

FAQ

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