Garden and Farm Calculators — Compost, Fertiliser, Seed, Irrigation, Acreage, Feed and Yield

Ten calculators for the arithmetic behind a vegetable patch, a lawn, a paddock or a working farm. They turn dimensions into volumes and areas, areas into seed, fertiliser and water, and animals into feed and grazing land, with imperial and metric inputs accepted throughout. Everything runs in the browser and nothing is stored.

Every Garden and Farm Calculators tool

Compost

The compost calculator takes the dimensions of a bin or heap, tells you whether it is big enough to heat up, how many barrowloads of greens and browns fill it at your chosen ratio, how much finished compost to expect and what area it will mulch. The table gives the carbon to nitrogen ratio of common materials.

Fertiliser and NPK

The fertiliser and NPK calculator converts an application rate in grams per square metre, kilograms per hectare or pounds per thousand square feet into the weight of product to buy from its N-P-K analysis, with the actual nitrogen, phosphate and potash delivered and the number of bags. The table shows the rate for a dozen common fertilisers at the same nutrient target.

Plant spacing

The plant spacing calculator works out how many plants fit a bed or border at a given spacing in a square or triangular grid, or the spacing needed for a set number of plants, using metric or feet and inches. Typical spacings for vegetables, hedging and bedding are listed for reference.

Grass seed

The grass seed calculator gives the lawn area from its length and width, the seed for a new lawn or overseeding at the rate for the mix you choose, the number of bags and how to split the seed for even sowing.

Raised beds

The raised bed calculator turns the size and depth of one or more beds into the volume of soil, compost and topsoil to order, in cubic metres, litres, bags and bulk bags, with an allowance for settling. Dimensions can be entered in metres, centimetres or feet and inches.

Irrigation

The irrigation calculator takes the area, how much water the plants need in millimetres a week, the rain you have had and how many days you water, and gives the litres per session, the run time at your hose or drip line flow, the watering cans that represents and what it adds to a water meter each month.

Field area and acreage

The field area calculator converts a field's length and width in metres, feet, yards or chains into acres, hectares and square metres, with the perimeter and post count for fencing and the diagonal for checking square corners. The table compares the area with football pitches, tennis courts and house plots.

Livestock feed

The livestock feed calculator budgets hay, haylage, silage or straw for cattle, sheep, goats, horses and alpacas from their dry matter intake, giving the amount per head per day, the total for the winter, the number of bales and a waste allowance.

Stocking rate

The stocking rate calculator works out how many animals a field can graze from its area, the grass it grows, the utilisation rate and the length of the season, in head per hectare and per acre and in livestock units, with a table across pasture qualities from rough hill to a ryegrass ley.

Crop yield

The crop yield calculator turns the weight harvested from a sample plot into tonnes per hectare, tonnes per acre and bushels per acre, corrects grain to its standard moisture, multiplies the figure up to the whole field and compares it with a typical yield for the crop.