GardenCalc is a free library of project calculators for home gardeners, cut-flower growers and anyone growing in a small space. Instead of generic soil or spacing maths, each tool answers a specific job: how many flowers to grow for weekly bouquets, how many plants fit a window box, how much netting covers a fruit cage, or how much salad to sow each week.
What makes our calculators different
- Project outputs, not just numbers. You get layouts, cut lists, sowing schedules and shopping lists.
- Transparent formulas. Every page explains the method, shows a worked example and lists its assumptions.
- Editable assumptions. Crop yields and spacings vary by variety and climate, so defaults are starting points you can change.
- Worldwide units. Every tool works in metric and imperial, and never assumes your hemisphere or season.
- Private by design. Calculations run in your browser. We do not store what you enter.
How we build and check tools
Each calculator is tested against typical, minimum, fractional and invalid inputs, and against the worked example published on its page. Read our editorial policy for details.
Spotted a mistake or have an idea for a tool? Get in touch.