Nepali Land Converter
Convert Ropani, Aana, Paisa, Daam and Bigha, Kattha, Dhur to square feet, square metres, acres and hectares, and see how big the area really is.
SpecSheet 005
- Status
- Live
- Role
- Sole developer
- Year
- 2022
- Language
- TypeScript
- Platform
- Web
- Stack
- Next.js
- React
- TypeScript
- Motion
Contents · 4 chapters
The problem
Land in Nepal is measured in two unit families, the hill system (Ropani, Aana, Paisa, Daam) and the Terai system (Bigha, Kattha, Dhur), and the numbers are hard to picture.
This converter handles both, and draws the area to scale next to something familiar.
The system
5 components · 5 connections · 1 request flow
A client-side app. One conversion engine stores every area as square feet, and each view of the result reads from it.
Play a request
- Client
- Service
- Data / control flow
- The request
Select a component to see its role, the technology behind it and what it talks to — or play a request and watch it travel the system.
Arrow keys move between components, Home and End jump to the first and last. Enter or Space selects one; Escape clears. Plus and minus zoom, 0 fits the map.
Component reference5 components · 1 flow · as text
Components · in request order
- Client · layer 01Converter
- Type into any unit system and the others update as you type. Supports partial input, stepping, and a shareable link to the current area.
- TechReact, Next.js
- FromQuick reference (load a unit)
- ToConversion engine (value + unit)
- Service · layer 02Conversion engine
- Defines each unit by its exact square-foot value (1 ft = 0.3048 m exactly) and converts every system through square feet.
- Lives in lib/land.ts and is covered by lib/land.test.ts.
- TechTypeScript
- FromConverter (value + unit)
- ToSense of scale (m² / ft²); Unit anatomy; Quick reference
- Client · layer 03Sense of scale
- Draws the area as a square plot beside a familiar reference such as a parking space or a football pitch, with side length and wall length.
- TechMotion
- FromConversion engine (m² / ft²)
- Client · layer 03Unit anatomy
- Shows how each unit nests inside the next and fills in the area you entered.
- TechMotion
- FromConversion engine
- Client · layer 03Quick reference
- One of each unit, calculated by the same engine.
- FromConversion engine
- ToConverter (load a unit)
Request flows
Convert an area
Typing a value in any system converts it through square feet and updates every other system, plus the scale drawing.
- Step 1: Converter
- Step 2: Conversion engine
- Step 3: Sense of scale
Decisions & trade-offs
4 decisions
Store everything as square feet
Each unit is defined by its exact square-foot value and 1 ft is exactly 0.3048 m, so every system converts through one engine instead of pairwise conversion tables.
Show scale, not just numbers
The area is drawn as a square plot next to a reference such as a parking space, a court or a football pitch, because a figure like 5,476 sq ft means little on its own.
Test the engine
The conversion logic is isolated in one module with its own tests.
Planning figures, not legal ones
Results are for planning and comparison. The Lalpurja and the Survey Office measurement remain the legal record.
The write-up
The following is a partial list of everyday units used to calculate land area in Nepal.
1 Bigha (बिघा) = 20 Kattha (कठ्ठा) = 6772.63 m² = 72900 sq.ft. = 13.31 Ropani
1 Katha (कठ्ठा) = 20 Dhur (धुर) = 338.63 m² = 3645 sq.ft.
1 Dhur (धुर) = 16.93 m² = 182.25 sq.ft.
1 Ropani (रोपनी) = 16 Aana (आना) = 64 Paisa (पैसा) = 508.72 m² = 5476 sq.ft. = 256 Daam (दाम) = 4 llka [4]
1 Aana (आना)= 4 Paisa (पैसा) = 31.80 m² = 342.25 sq. ft. = 16 Daam (दाम)
1 Paisa (पैसा) = 4 Daam (दाम) = 7.95 m² = 85.56 sq. ft.
1 Daam (दाम) = 1.99 m² = 21.39 sq. ft.
Units of Measurement
The units of measurement of the area of land depend on the part of the country where they are being used, with the Bigha-Katha-Dhur measurements common in the Terai region while the Ropani-Aana measurements are common in hilly and mountainous regions.
