Calculators for every part of the garden
Most garden jobs are one of three things: filling space with material, feeding or watering plants, or laying out how many things to buy. The tools here cover each, starting from the area you measure.
- Mulch Calculator – Cubic yards and bags of mulch for beds, borders and tree rings.
- Compost Calculator – Cubic yards and bags of compost for lawns, beds and new planting areas.
- Raised Bed Soil Calculator – Soil volume and blend amounts for raised garden beds.
- Grass Seed Calculator – Pounds of grass seed for a new lawn or overseeding, by grass type.
- Lawn Fertilizer Calculator – Pounds of fertilizer and bags needed for your lawn from the N rate and bag analysis.
- Lawn Watering Calculator – Gallons per week and sprinkler run time for your lawn.
- Pond Volume Calculator – Gallons or litres in a pond, with pump flow and liner size.
- Plant Spacing Calculator – How many plants you need for a bed, border or hedge at a given spacing.
- Lawn Area Calculator – Square feet and acres of an irregular lawn, with quick seed and fertilizer amounts.
- Garden Path Calculator – Gravel, base stone, pavers and sand for a garden path or walkway.
- Artificial Grass Calculator – Turf to order, seams, base rock and infill for an artificial lawn.
- Rainwater Harvesting Calculator – Gallons or litres a roof collects from rain, and barrels needed.
- Potting Soil Calculator – How much soil or potting mix fills a pot, planter or window box.
- Firewood Cord Calculator – Cords, face cords and the real price per cord of a firewood stack.
Which calculator do I need?
If you are building a bed, use the raised bed soil calculator for the fill and the compost and mulch calculators to improve and finish it. Work out the number of plants with the plant spacing calculator, and use the potting soil calculator for pots and containers.
If you are caring for a lawn, start with the lawn area calculator, which adds and subtracts shapes, then use the grass seed, lawn fertilizer and lawn watering calculators. A new lawn can also use the sod calculator in Home & DIY, or the artificial grass calculator if you want turf that needs no mowing.
If you are adding hardscape or water, use the garden path calculator for gravel and pavers, the pond volume calculator for fish ponds and water features, and the rainwater harvesting calculator to see how much your roof can supply. The firewood calculator checks a cord before you pay.
Measuring a garden
Measure each bed at its widest and narrowest points and use the average, break odd shapes into rectangles and circles, and add them up. Check depths with a ruler, not by eye: a one-inch error across a large bed changes the order by a full cubic yard or more.
Fertilizer, pesticide and water safety
Always follow the product label and keep chemicals away from children, pets and waterways. Check local rules on fertilizer use and watering restrictions, and test your soil before adding nutrients you may not need. For heavy or structural work such as retaining walls and ponds with deep water, follow local regulations and consider professional advice.
Frequently asked questions
Are the garden calculators free?
Yes. Every calculator on CalcTen is free to use with no sign-up. The site is supported by advertising.
Where do the garden rates and depths come from?
From university extension services and manufacturers, such as Oregon State, Iowa State, Nebraska, Illinois, UC IPM and the University of Arizona. Each guide links to its sources, and rates you can change are shown as editable fields.
Do the lawn tools suit my grass type and climate?
The seed and fertilizer tools list rates by grass type, but timing and grass choice depend on your region. Check your local extension service for dates and any limits on fertilizer or watering.
Can I use metric units?
Yes. Switch between feet and inches and metres on any calculator. Soil and mulch results appear in cubic yards or cubic metres, and bag sizes can be entered in cubic feet or litres.
How accurate are the results?
The maths is exact for the numbers you enter. Soil settles, beds are rarely perfect rectangles and products vary, so the tools include allowances. Measure carefully and round up when buying.
Are fertilizer and weed-control results safe to follow blindly?
No. The calculators work out quantities, but you must follow the product label, which is the legal instruction for rates, timing and safety, and check local rules.