Convert Arpent (French) to Square Kilometer
Convert arpents to square kilometers instantly. 1 arpent (french) = 0.004221 square kilometer — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Square Kilometer to Arpent (French) converter for the reverse conversion.
Units explained
Arpent (French)
A French arpent is a historical unit of land area used in pre-metric France, approximately 4221 m² (close to one acre).
Originated as a medieval French land unit; varied considerably by province. The 'arpent de Paris' was officially fixed at 100 perches squared, the perche being 18 pieds.
French arpents appear in pre-revolutionary French land records and in genealogical research. The unit was largely abolished after the French Revolution in favor of metric units.
Medieval French origin; abolished after the French Revolution in favor of metric.
Square Kilometer
A square kilometer is a metric unit of area equal to 1,000,000 m² (one million square meters), or 100 hectares. It is used for measuring large land areas, regional geography, and country-scale statistics.
Derived by squaring the kilometer (1000 m). The kilo- prefix comes from the Greek 'chilioi' (thousand).
Square kilometers express the area of cities, districts, lakes, forests, and entire countries. India's total area is approximately 3,287,263 km². 1 km² equals 100 hectares or about 247.105 acres.
Kilometer has been part of the metric system since 1795.
Arpent (French) to Square Kilometer conversion formula
The relationship between arpents and square kilometers:
To convert arpents to square kilometers, multiply the value in arpents by 0.004221. To reverse, multiply square kilometers by 236.9106846719.
How to use this converter
Type a value into the calculator. The result in square kilometers updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Square Kilometer to Arpent (French) converter for the reverse direction.
Step-by-step: convert arpents to square kilometers
- Write down the value in arpents (arpent).
- Multiply that value by the factor 0.004221.
- The product is the equivalent value in square kilometers (km²).
- To reverse, multiply the square kilometer value by 236.9106846719.
Worked examples
Example 1 — Convert 1 arpent to km²:
1 × 0.004221 = 0.004221 km²
Example 2 — Convert 100 arpent to km²:
100 × 0.004221 = 0.4221 km²
Real-world example — Coastal cruise distances
A 10-arpent (french) coastal sailing route converts to a different value in square kilometers — useful for cruise operators who switch between maritime, aviation, and road-distance units depending on the leg of the trip.
10 arpent × 0.004221 = 0.04221 km²
Real-world example — Road-sign distances across systems
A 100-arpent (french) road sign converts cleanly into square kilometers — exactly the conversion drivers planning trips abroad rely on when reading road signs in a different measurement system.
100 arpent × 0.004221 = 0.4221 km²
Real-world example — Endurance race distances
A 50-arpent (french) cycling or running race converts to a recognizable distance in square kilometers. Endurance athletes coming from a different measurement system use this conversion to compare training plans across regions.
50 arpent × 0.004221 = 0.21105 km²
Arpent (French) to Square Kilometer conversion table
Standard reference values for converting arpents to square kilometers:
| Arpent (French) [arpent] | Square Kilometer [km²] |
|---|---|
| 0.01 | 4.221e-5 |
| 0.1 | 0.0004221 |
| 1 | 0.004221 |
| 2 | 0.008442 |
| 3 | 0.012663 |
| 4 | 0.016884 |
| 5 | 0.021105 |
| 10 | 0.04221 |
| 20 | 0.08442 |
| 30 | 0.12663 |
| 40 | 0.16884 |
| 50 | 0.21105 |
| 100 | 0.4221 |
| 500 | 2.1105 |
| 1000 | 4.221 |
Frequently asked questions
How many square kilometers is 1 arpent (french)?
How do I convert arpents to square kilometers?
How do I convert square kilometers back to arpents?
How many square kilometers is 100 arpents?
Popular area unit conversions
Convert Arpent (French) to other area units
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Metric / SI (5 units)
Imperial / US Customary (3 units)
Other Regional (9 units)
Sources & references
Conversion factor (1 arpent = 0.004221 km²) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.