Patch Plants has free garden calculators and plant tools that take the guesswork out of planning, from how much soil and mulch to buy to which plants suit your space. Pick a tool below, enter your measurements, and get a clear answer in seconds.
Soil Calculator
Work out how much soil you need for raised beds, garden beds and containers, in cubic feet, cubic yards and bags.
Mulch Calculator
Find out how many cubic yards or bags of mulch to buy for beds, tree rings and round areas, with a built-in settling allowance.
More tools on the way
Pet-Safe Plant Checker
Check whether a houseplant is safe for cats and dogs, based on ASPCA data.
Coming soon
Planting Zone Finder
Find your hardiness zone and last frost date from your zip code.
Coming soon
Companion Planting Chart
See which plants grow well together and which to keep apart.
Coming soon
Seed Starting Calculator
Get indoor seed starting and transplant dates for your area.
Coming soon
Plant Spacing Calculator
Work out how far apart to plant and how many plants fit in a bed.
Coming soon
Grass Seed Calculator
Estimate how much grass seed a lawn needs for new seeding or overseeding.
Coming soon
How These Garden Calculators Work
Each calculator uses the same simple approach: you tell it the size and depth of the area, it works out the volume, and it adds a small allowance for settling so you do not run short. Results are shown in both US and metric units where it matters, and you can add several beds to get one total.
The numbers behind each tool are checked against trusted sources such as the Royal Horticultural Society and university extension services, so recommended depths and spacings reflect real horticultural guidance rather than guesswork. They are planning aids, so always check the label of the product you buy.
Which Tool Should You Use?
- Filling a new raised bed or pots? Start with the soil calculator, then read our guide to the best soil mix for every type of plant.
- Finishing a bed or protecting tree roots? Use the mulch calculator once the planting is done.
- Planning the year ahead? Our garden calendar shows which jobs belong in each season.
Every tool at Patch Plants is built and reviewed by botanist Sawera Shahid, the same person who writes our plant guides, so the advice on the page and the maths in the calculator agree with each other. New tools are added regularly, and the ones marked coming soon above are already in progress.
Frequently Asked Questions
Are the garden calculators free to use?
Yes. Every calculator on this page is free, and you do not need to create an account or enter an email address to use it.
How accurate are the results?
The volume and coverage sums are exact for the measurements you enter, but real beds are rarely perfect. That is why the calculators add a small allowance for settling and uneven edges. Treat the result as a reliable estimate, and round up when you order.
Can I use metric units?
Yes. The calculators let you switch between US units (feet, inches, cubic yards) and metric units (metres, centimetres, cubic metres), and the results update to match.
Can I calculate more than one bed at once?
Yes. The mulch calculator lets you add several areas, including rectangles, circles and tree rings, and gives you one combined total. Calculating beds separately is also fine if you plan to buy in different batches.
Which garden tools are coming next?
We are working on a pet-safe plant checker, a planting zone finder, a companion planting chart, a seed starting calculator, a plant spacing calculator and a grass seed calculator. Check back soon, or browse our plant guides in the meantime.