---
title: "Building rule calculators"
method: POST
path: "/api/v1/tools/building_rule_calc"
---

# Building rule calculators

`POST /api/v1/tools/building_rule_calc`

## Request

- Base URL: `https://verified.realestate`
- URL: `https://verified.realestate/api/v1/tools/building_rule_calc`
- Auth: HTTP bearer

Free single-answer TNCDBR 2019 calculators. subject picks the rule: "setback" (front/rear/side metres; needs road_width_m + frontage_m + floors, flags cba/ews/highrise honored), "osr" (open space reservation for a layout; needs total_area_sqm), "ews_reservation", "public_purpose", "development_type" (layout vs subdivision; needs total_area_sqm + road_width_m + location_type), "passage_width" (private passage; plots_served + passage_length_m), "street_width" (public street; street_length_m + plots_served), "splay" (needs road_width_m), "service_road" (abuts_highway true/false), "scrutiny_fee" (needs total_area_sqm), "self_certification" (plot_area_sqm + built_up_area_sqm + height_m), "building_class" (the TNCDBR 2019 building category: high rise, industrial, institutional, or a non high rise small or larger development; max_height_m + housing_units + commercial_area_sqm + use, floors only when the height is unknown), "gcc_tier" (Chennai approval tier; built_up_area_sqm + max_height_m). Areas in SQ.M (convert: 1 acre=4046.86, 1 ground=222.97, 1 cent=40.47, 1 sq.ft=0.0929), lengths in METRES. For full FSI / floors / parking with a setback diagram, offer the Build Scope report instead. Free.

## Request body

- object
  - `subject` 'setback' | 'osr' | 'ews_reservation' | 'public_purpose' | 'development_type' | 'passage_width' | 'street_width' | 'splay' | 'service_road' | 'scrutiny_fee' | 'self_certification' | 'building_class' | 'gcc_tier', required
  - `total_area_sqm` number
  - `plot_area_sqm` number
  - `built_up_area_sqm` number
  - `commercial_area_sqm` number
  - `road_width_m` number
  - `frontage_m` number
  - `floors` integer
  - `housing_units` integer
  - `max_height_m` number
  - `height_m` number
  - `plots_served` integer
  - `passage_length_m` number
  - `street_length_m` number
  - `location_type` 'cma' | 'peri_urban' | 'corporation' | 'municipality' | 'town_panchayat' | 'village_panchayat' | 'industrial'
  - `abuts_highway` boolean
  - `cba` boolean
  - `ews` boolean
  - `highrise` boolean
  - `use` 'residential' | 'commercial'

## Response `200`

The envelope: ok, status, data, credits_charged, balance_after, request_id

## Other responses

- `401`: No valid credential
- `402`: Not enough credits
- `429`: Rate limit

---

[API](https://skmtc.dev/verified/apis/landlens-tool-api.md) · [All operations](https://skmtc.dev/verified/apis/landlens-tool-api/llms.txt) · [OpenAPI document](https://skmtc.dev/verified/apis/landlens-tool-api/revisions/54f851c86cc1?raw)