Free garden calculators: Soil volume, mulch, plant spacing, fertilizer, sprinkler, drip irrigation, and bed layout — plan your perfect garden online.
GardenMetric is a free hub of twelve garden and landscaping calculators that turn rough estimates into the actual quantities you buy and the schedules you follow. Instead of guessing how many bags of soil a raised bed needs or how long to run a sprinkler, you enter real measurements and get numbers in the units retailers and equipment use — cubic feet, cubic yards, gallons, inches per week, plants per row, and pounds of fertilizer. Every tool runs entirely in your browser, needs no sign-up, and works the same on a phone in the garden as on a desktop while you plan.
The collection spans the four jobs that drive most garden spending. For beds and ground, the soil volume and mulch calculators convert length, width, and depth into cubic feet, cubic yards (1 cubic yard = 27 cubic feet), and retail bag counts — 1.5-cubic-foot soil bags and 2-cubic-foot mulch bags by default. For planting, the plant spacing, garden layout, and companion planting tools tell you how many plants fit a bed, how to arrange rows, and which crops grow well together. For feeding and watering, the fertilizer NPK, sprinkler, and drip irrigation calculators size nutrient doses and run times. Finally, the compost C/N ratio, growing degree days, sunlight-by-latitude, and pesticide dilution tools handle the timing and chemistry that decide whether the rest of the plan succeeds.
Each calculator uses the standard horticultural formula for its task and shows the working units so you can sanity-check the output. Volumes assume a uniform depth, so for sloped or trapezoidal beds you should calculate each section separately and add the results. Bag counts round up because partial bags are not sold, and bulk soil estimates include a settling allowance because peat and compost compact once watered. Irrigation results depend on your soil type and climate, so treat them as a starting schedule and adjust after watching how quickly your beds dry out. The numbers are designed to be conservative enough to avoid under-ordering without sending you home with a trunk full of leftover material.
GardenMetric is built for home gardeners planning a first raised bed, allotment holders rotating vegetable plots, and landscapers pricing soil, mulch, and irrigation for clients. Because the tools share consistent units and assumptions, you can move from one to the next as a project grows — size the bed with the layout tool, fill it with the soil volume calculator, top it with mulch, space the seedlings, then set a feeding and watering schedule — without re-measuring or converting by hand. The interface is available in sixteen languages so the same math is accessible whether you garden in metric or imperial habits.
No. Every calculator on GardenMetric is free and runs in your browser with no sign-up, login, or payment. Your inputs are not stored on a server.
Yes. The tools accept the units shown beside each field and report results in the units most useful for buying materials — for example cubic feet and cubic yards for soil, plus an estimated bag count so you know how much to purchase.
Each tool uses the standard formula for its calculation, so the math is exact for the inputs you provide. Real-world accuracy depends on how precisely you measure your space and on variables like soil settling and weather, which is why volume estimates round up and irrigation figures should be fine-tuned after observing your garden.