TRANSPARENT BY DESIGN

Calculator formulas, units & sources

These calculators turn measurements into geometric area, volume, and estimated material weight. The formulas below explain what is calculated and where an assumption is needed.

Methodology updated August 28, 2026.

Area

Rectangle area is length multiplied by width. Circle area is π multiplied by the square of the radius; the tool accepts a diameter and divides it by two. Triangle area is base multiplied by perpendicular height, divided by two.

Dimensions are converted to feet before calculating. Separate areas are added without subtracting overlaps or openings. Extra material is measured area × percentage ÷ 100. It is an order allowance, not an increase in the physical floor area.

Volume

Volume in cubic feet is area in square feet multiplied by depth in feet. Divide by 27 to convert to cubic yards. With depth in inches, cubic yards = square feet × depth ÷ 324.

The tool assumes a uniform depth. For different depths or different material layers, calculate each section separately. It does not model slopes, excavation swelling, or settlement.

Gravel density assumptions

Weight in US short tons = volume in cubic yards × bulk density in US short tons per cubic yard. Bulk density includes the spaces between particles and changes with grading, moisture, and packing.

The presets are chosen within the general ranges published by Inch Calculator. They are illustrative assumptions, not certified material measurements or supplier specifications. Enter your supplier’s bulk density whenever available.

Extra material defaults to 0%. No standard compaction percentage is applied. A stated reduction in volume is not the same as adding that percentage to an order. Ask your supplier which loose and installed volumes apply to the actual product.

Unit definitions

• 1 foot = 12 inches = exactly 0.3048 meters.
• 1 yard = 3 feet; 1 square yard = 9 square feet.
• 1 cubic yard = 27 cubic feet = exactly 0.764554857984 cubic meters.
• 1 square foot = exactly 0.09290304 square meters.
• 1 acre = 43,560 square feet.
• 1 US short ton = 2,000 pounds = exactly 907.18474 kilograms.
• 1 metric tonne = 1,000 kilograms. British long tons are not used.

The length conversions follow the international inch and yard definitions described by NIST. Area and volume conversions are derived by squaring and cubing the length factors.

For the mass conversion, NIST Handbook 44 (2026) lists 1 pound as 0.45359237 kilograms. Multiplying by 2,000 gives the US short ton conversion used here. Material density is a separate assumption, not part of this unit definition.

Rounding and prices

Calculations use unrounded intermediate values. Results normally display two decimal places; small nonzero numbers retain significant digits. Bag estimates round up to the next whole bag. An entered unit price of zero is valid; a blank price means no cost estimate.

Prices are entered by you in USD. Estimated material cost excludes labor, delivery, tax, equipment, and minimum-order charges. Bulk order quantities are not rounded to supplier increments. Bag-based costs use the whole-bag count.

Accuracy and intended use

Calculations run in your browser. The repository includes automated checks for geometry, units, extra allowances, costs, invalid inputs, and bag rounding. Calculations can still be limited by the accuracy of your measurements and assumptions.

These are planning tools, not construction designs, certified surveys, property appraisals, or supplier quotations. Obtain qualified advice for structural projects and confirm purchase quantities with your supplier.

Content and corrections

Each calculator has a visible formula, a worked example, and limitations. No professional credential, product review, or customer rating is claimed. To check a result, compare the input units and the formula shown on the page. For material orders, verify assumptions with the supplier before purchasing.