How To Calculate The Are

Calculate land area in ‘are’ units with precision. Enter measurements in meters, feet, or acres.

Comprehensive Guide: How to Calculate the Are (Unit of Area)

The are (symbol: a) is a metric unit of area equal to 100 square meters (10m × 10m), primarily used for measuring land area. While not as commonly used as hectares or square meters in modern contexts, the are remains an important unit in agriculture, forestry, and land management—particularly in European countries. This guide explains how to calculate area in ares, convert between units, and apply these calculations in practical scenarios.

Key Facts About the Are

• 1 are (a) = 100 square meters (m²)
• 1 hectare (ha) = 100 ares
• 1 are ≈ 119.6 square yards
• 1 are ≈ 0.0247 acres
• Originally defined in the metric system (1795)

Common Uses of the Are

• Small land parcels (e.g., gardens, allotments)
• Agricultural plots in Europe
• Forestry management
• Historical land records
• Urban planning in some countries

Step-by-Step: Calculating Area in Ares

1. Measure the dimensions of the land parcel in meters (or convert other units to meters).
   • For rectangles/squares: measure length and width.
   • For circles: measure the diameter (length) or radius.
   • For triangles: measure base and height.
2. Calculate the area in square meters (m²) using the appropriate formula:

   Shape	Formula	Example (5m × 10m)
   Rectangle	Length × Width	5m × 10m = 50 m²
   Square	Side × Side	5m × 5m = 25 m²
   Circle	π × (Radius)²	π × (2.5m)² ≈ 19.63 m²
   Triangle	(Base × Height) / 2	(5m × 10m) / 2 = 25 m²

3. Convert square meters to ares:

   Since 1 are = 100 m², divide the area in m² by 100:

   Area in ares = (Area in m²) / 100

   Example: 50 m² ÷ 100 = 0.5 ares

Converting Other Units to Ares

If your measurements are in feet, yards, or acres, first convert them to square meters, then to ares.

Unit	Conversion Factor to m²	Example (1 unit → m² → ares)
Square Feet (ft²)	1 ft² = 0.092903 m²	100 ft² → 9.29 m² → 0.0929 ares
Square Yards (yd²)	1 yd² = 0.836127 m²	100 yd² → 83.61 m² → 0.8361 ares
Acres	1 acre = 4046.86 m²	0.1 acre → 404.69 m² → 4.0469 ares
Hectares (ha)	1 ha = 100 ares	0.5 ha → 50 ares

Practical Applications of the Are

The are is particularly useful for:

1. Small-scale agriculture: Many European farms measure plots in ares for crops like vineyards or vegetable gardens.

   “In France, the are is still commonly used for vineyard parcels, where 1 are can produce approximately 500–700 bottles of wine, depending on the grape variety and density.” — French Ministry of Agriculture

2. Urban gardening: Allotment gardens in cities like Berlin or Paris are often allocated in ares (e.g., 20–50 ares per family).
3. Forestry: Reforestation projects may measure sapling density per are (e.g., 100 trees/are).
4. Historical land records: Older deeds in metric-adopted countries often use ares.

Common Mistakes to Avoid

• Confusing ares with hectares: 1 hectare = 100 ares, not 1 are.
• Incorrect unit conversions: Always convert to square meters first, then to ares.
• Ignoring land shape: Use the correct formula (e.g., triangles vs. rectangles).
• Rounding errors: For precision, keep intermediate calculations to 4+ decimal places.

Advanced Calculations: Irregular Shapes

For irregular plots, divide the land into simpler shapes (e.g., triangles/rectangles), calculate each area, then sum them:

1. Sketch the plot and divide it into measurable sections.
2. Measure each section’s dimensions.
3. Calculate each section’s area in m², then convert to ares.
4. Sum all areas for the total.

Example: A plot divided into a 10m × 15m rectangle and a triangular section (base 10m, height 5m):

Rectangle: 10 × 15 = 150 m² → 1.5 ares

Triangle: (10 × 5)/2 = 25 m² → 0.25 ares

Total: 1.75 ares

Tools for Measuring Land Area

Traditional Tools

• Measuring tape: For small, regular plots.
• Surveyor’s wheel: For longer distances.
• GPS devices: For irregular or large plots.

Digital Tools

• Google Earth: Use the “Measure” tool for approximate areas.
• GIS software: QGIS or ArcGIS for professional mapping.
• Mobile apps: “Land Calculator” or “Area Calculator” apps.

Historical Context of the Are

The are was introduced during the French Revolution as part of the metric system (1795) to standardize land measurement. It was defined as the area of a square with 10-meter sides, making it practical for small landholdings. While largely replaced by hectares for larger areas, the are persists in:

• Legal documents: Property deeds in France, Belgium, and Switzerland.
• Agricultural subsidies: EU Common Agricultural Policy (CAP) sometimes uses ares for small farms.
• Education: Teaching metric conversions in schools.

For further reading, see the NIST Guide to the SI Metric System.

Comparison: Are vs. Other Land Area Units

Unit	Equivalent in m²	Equivalent in Ares	Primary Use
Square Meter (m²)	1	0.01	Small areas (rooms, gardens)
Are (a)	100	1	Small land parcels
Hectare (ha)	10,000	100	Large farms, forests
Acre	4,046.86	40.4686	Farmland (US, UK)
Square Foot (ft²)	0.092903	0.000929	Real estate (US)

Frequently Asked Questions

1. Why is the are still used?

   The are provides a convenient middle ground between square meters (too small for land) and hectares (too large for small plots). It’s especially useful in countries where landholdings are traditionally small, such as parts of Europe and Asia.

2. How do I convert ares to acres?

   1 are ≈ 0.0247105 acres. Multiply ares by 0.0247105 to get acres.

   Example: 10 ares × 0.0247105 ≈ 0.247 acres.

3. Is the are used outside Europe?

   While rare, the are appears in some African and Asian countries with metric systems, particularly in agricultural contexts. However, hectares or square meters are more common globally.

4. Can I use Google Maps to measure ares?

   Yes. In Google Earth:

   1. Click the “Measure” tool (ruler icon).
   2. Draw the boundaries of your land.
   3. Note the area in m², then divide by 100 for ares.

Case Study: Calculating Ares for a Vineyard

A vineyard in Bordeaux, France, has the following dimensions:

• Three rectangular plots: 20m × 30m, 15m × 25m, and 10m × 40m.
• A triangular plot with base 20m and height 15m.

Step 1: Calculate each plot’s area in m²:

• 20 × 30 = 600 m²
• 15 × 25 = 375 m²
• 10 × 40 = 400 m²
• (20 × 15)/2 = 150 m²

Step 2: Sum the areas: 600 + 375 + 400 + 150 = 1,525 m².

Step 3: Convert to ares: 1,525 ÷ 100 = 15.25 ares.

This vineyard would be recorded as 15.25 ares in local land registries.

Regulatory Considerations

When using ares for legal or commercial purposes:

• Precision requirements: Some countries mandate measurements to the nearest 0.01 are for property transactions.

  “In Switzerland, land area measurements for cadaster purposes must be accurate to within 0.05 ares.” — Swiss Federal Office of Topography

• Surveyor certification: For official documents, measurements must often be performed by a licensed surveyor.
• Unit consistency: Always confirm whether the local standard expects ares, hectares, or square meters.

Future of the Are

While the are is less common today, it remains relevant in:

• Historical preservation: Maintaining consistency in old records.
• Niche agriculture: Vineyards, orchards, and market gardens.
• Education: Teaching metric conversions and land measurement.

For most modern applications, hectares or square meters are preferred, but understanding ares is valuable for working with older documents or specific industries.