Home and garden calculators
Outdoor projects — filling a pool, seeding a lawn, or spreading mulch and gravel — involve the same basic challenge as indoor construction: translating area and depth measurements into quantities you can actually buy. Doing this arithmetic before you go to the garden centre or pool supply shop means you can compare product quantities with confidence rather than guessing in the aisle.
The calculators in this category
The Pool Volume Calculator estimates the water volume of rectangular, circular, and oval pools in gallons and litres. This is useful for planning initial fills, calculating how long a hose will take to fill the pool at a known flow rate, and as a starting point for chemical treatment planning (though actual dosing must follow product labels and water testing).
The Lawn Seed and Fertilizer Calculator takes a lawn area and calculates how much grass seed and fertilizer you need based on the recommended application rate. It covers both new lawn establishment and overseeding, which require different seeding rates. Results are in kg and lbs, switchable by unit system.
Start with accurate area measurements
For ground-cover materials — mulch, topsoil, gravel, lawn seed — area multiplied by depth (or application rate) gives the quantity you need. Accurate measurements are more valuable than false precision in the final number. For a lawn, walk the perimeter and sketch the shape before entering dimensions. For irregular shapes, break the area into rectangles and add them up; the total will be close enough for ordering purposes.
Product labels are always authoritative
Seed mixes, fertilizer products, pool chemicals, and other garden materials have recommended application rates printed on the packaging. These rates are specific to the product's formulation and concentration, which varies between brands. Use a calculator to perform the basic area arithmetic, then check the quantity against the rate on the product you are buying. Some products also include safety and timing instructions that affect how the material is applied.
Pool volume is a planning estimate, not a dosing guide
Knowing the approximate water volume in gallons or litres is useful for understanding scale — how long a fill will take, what treatment products cost per fill, and roughly how much water the pool holds. However, actual chemical dosing should always be based on tested water conditions using a pool test kit or professional water testing, combined with the dosing instructions on the specific product. Volume alone is not enough information to determine correct chemical levels.
Allow for waste and irregular terrain
On real ground, slight unevenness, slope, and compaction mean that calculated quantities are starting estimates rather than exact requirements. For larger projects, it is usually worth adding a small contingency — 5 to 10 percent — and noting the coverage rate on the bag in case a top-up is needed later.