When to use this calculator
Estimate soil volume for a straight-sided round planter. Assumes a cylindrical container, not a tapered planter. Deduct drainage layers separately.
Explore the plant spacing, soil & seed calculators for other questions in this topic. For a related calculation, use the Seed Germination Adjustment Calculator: Adjust seed count for a chosen expected germination percentage.
PUTTING IT INTO PRACTICE
Round Planter Soil: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Internal top diameter (cm) | 40 |
| Filled height (cm) | 30 |
| Result | 37.699112 L |
- Check the input labels and enter the example values above.
- Apply the relationship: Cylindrical fill litres = π(diameter/2)² × height/1000.
- The result is 37.699112 L, rounded for display.
How to interpret your result
Assumes a cylindrical container, not a tapered planter. Deduct drainage layers separately.
Usable area and boundaries affect actual plant count. Product-specific seed rates and germination assumptions are entered rather than recommended. Volume-based soil estimates can change with settling, moisture and compaction.
Frequently asked questions
Does a plant-count estimate choose suitable crop spacing?
No. You choose spacing appropriate to the crop and growing conditions. The calculator translates that spacing into a geometric count.
When is the round planter soil calculator useful?
Estimate soil volume for a straight-sided round planter. Assumes a cylindrical container, not a tapered planter. Deduct drainage layers separately.
How do I use the round planter soil calculator?
Enter internal top diameter (cm), filled height (cm). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Cylindrical fill litres = π(diameter/2)² × height/1000.
What should I check before using the result?
Assumes a cylindrical container, not a tapered planter. Deduct drainage layers separately.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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