Potting Soil Calculator
Select your pot shape.
Formulas: Round: π × (radius²) × height, Square: side² × height, Rectangular: length × width × height.
Convert in³ to ft³ by dividing by 1728.
Enter the pot's diameter.
Enter the pot's height.
How many pots will you fill?
Calculated from the dimensions provided.
Formulas: Round: π × (radius²) × height, Square: side² × height, Rectangular: length × width × height.
Convert in³ to ft³ by dividing by 1728.
Ensure your pot has drainage holes to prevent waterlogging. A quality potting mix balances water retention with aeration. Consider additives like perlite or pumice for improved drainage. Adjust watering based on pot size, soil type, and plant needs.
Created by James S. Lockwood
With a background in botany and ecological sciences, James specializes in creating practical tools and resources to help gardeners, farmers, and plant enthusiasts optimize their green spaces.
Are you wondering how much potting soil you need for your plants? Our Potting Soil Calculator helps you determine the exact amount required for different pot shapes and sizes. Whether you’re planting bonsai, succulents, vegetables, or flowers, this tool makes it easy to calculate pot size, soil volume, and even cost estimation.
What is a Potting Soil Calculator?
A Potting Soil Calculator is an online tool designed to help gardeners, plant enthusiasts, and landscapers determine how much potting soil they need for their containers. It takes into account:
✔ Pot shape (Round, Square, Rectangular)
✔ Pot dimensions (Diameter, Width, Height)
✔ Number of pots (For bulk calculations)
✔ Soil type recommendations (Succulents, Bonsai, Vegetables, etc.)
✔ Bulk vs. Bagged soil comparison (Cost estimation included)
Instead of guessing how much soil to buy, use our calculator to get an accurate estimate for your plant pots, raised garden beds, and planters.
How Much Potting Soil Do I Need?
Calculating the right amount of potting mix is essential for healthy root growth and proper drainage. Using too little soil can stunt plant growth, while too much can lead to overwatering issues. Our calculator helps you measure the volume required based on:
✅ Pot shape (Round, Square, Rectangular)
✅ Pot dimensions (Diameter, Height, Length, Width)
✅ Number of pots (Total soil volume needed for multiple planters)
Quick Formula for Estimating Potting Soil:
- Round Pots: π × (radius²) × height
- Square Pots: Side² × height
- Rectangular Pots: Length × width × height
- Convert cubic inches to cubic feet by dividing by 1,728
Use the Potting Soil Calculator above to get an instant soil volume estimate!
Why Use a Potting Soil Calculator?
Many gardeners overestimate or underestimate the amount of soil they need, leading to wasted money or an insufficient supply. A potting soil calculator eliminates guesswork by:
✅ Preventing Soil Wastage – Buy exactly the amount of soil you need.
✅ Saving Money – Compare bulk vs. bagged options to find the most cost-effective purchase.
✅ Ensuring Proper Growth – Using the right amount of soil promotes healthy roots and prevents waterlogging.
✅ Customizing for Different Plants – Get precise soil recommendations for bonsai, succulents, vegetables, flowers, and more.
If you’re serious about plant health and soil optimization, using this tool will make your gardening projects easier and more efficient.
How to Use the Potting Soil Calculator?
1️⃣ Select the Pot Shape – Choose Round, Square, or Rectangular.
2️⃣ Enter Pot Dimensions – Input diameter, width, height, etc.
3️⃣ Choose the Number of Pots – Add multiple pots for bulk soil estimation.
4️⃣ Check Soil Volume Needed – Get results in cubic feet, gallons, and cubic yards.
5️⃣ Compare Bulk vs. Bagged Soil – Select the best purchasing option.
6️⃣ Estimate Cost – Input price per unit and delivery fees for a cost estimate.
📌 Tip: If you’re also fertilizing your soil, check out our Soil Fertilizer Calculator to ensure proper nutrient balance!
How to Calculate Pot Size for Your Plants?
Choosing the right pot size is crucial for plant health. The pot should be large enough for root expansion but not so big that it retains excessive moisture.
Herbs
🪴 6-8 inches deep Pot Size
📌 Shallow-rooted, compact pots
Vegetables
🪴 10-12 inches deep Pot Size
📌 Needs space for deep roots
Flowers
🪴 8-10 inches deep Pot Size
📌 Ensures proper bloom growth
Bonsai Trees
🪴 4-6 inches deep Pot Size
📌 Shallow pots, encourages root pruning
Succulents
🪴 Small, 3-5 inches Pot Size
📌 Well-draining pots, prevents rot
Cacti
🪴 Small, compact Pot Size
📌 Requires excellent drainage
Trees & Shrubs
🪴 18+ inches deep Pot Size
📌 Large containers recommended
Bonsai Pot Size Calculator – Find the Right Fit for Your Tree
Bonsai trees require specialized pots that balance aesthetics and root health.
📌 How to Choose a Bonsai Pot Size?
✔ Pot Length = About ⅔ of the tree’s height
✔ Pot Width = Matches the tree’s branch spread
✔ Pot Depth = Similar to the tree’s trunk thickness
Using our Bonsai Pot Size Calculator, you can determine the best container and soil volume for your bonsai tree without the hassle of manual calculations.
Potting Soil Volume Calculator – Bulk vs. Bagged Soil
One of the biggest gardening dilemmas is deciding whether to buy soil in bags or bulk. Our Potting Soil Volume Calculator helps you compare both options.
How to Calculate Soil Volume?
✅ Round Pots → π × (radius²) × height (Convert in³ to ft³ by dividing by 1,728)
✅ Square Pots → Side² × height
✅ Rectangular Pots → Length × width × height
📌 Conversions for Buying Soil:
- 1 Cubic Yard = 27 Cubic Feet
- 1 Cubic Foot = 7.5 Gallons
🌱 Buying Soil in Bags?
1️⃣ Check bag size (e.g., 1.5 cu ft, 2 cu ft)
2️⃣ Divide total soil volume by bag size
3️⃣ Get the exact number of bags needed
Example: If you need 10 cubic feet of soil, and each bag contains 2 cubic feet, you’ll need 5 bags.
Check out our Soil Calculator for raised beds and large gardens.
FAQs About Potting Soil & Pot Size
1. How much potting soil do I need for a 5-gallon pot?
A 5-gallon pot typically holds 0.67 cubic feet of soil. Use our calculator to adjust for multiple pots.
2. How do I know if my plant needs a bigger pot?
If roots are circling the inside of the pot, water drains too quickly, or growth is stunted, it’s time for a larger container.
3. Is bagged soil better than bulk soil?
Bagged soil is easier to handle, while bulk soil is more cost-effective for large projects. Our calculator helps you choose the best option!
4. Can I reuse old potting soil?
Yes, but it’s best to refresh it with compost or fertilizer to restore nutrients. Use our Soil Fertilizer Calculator to balance nutrients.
5. How do I improve soil drainage?
✔ Choose well-draining potting mix
✔ Add perlite or pumice
✔ Ensure pots have drainage holes
Disclaimer for Potting Soil Calculator
This calculator provides estimates only and should be used as a guideline. Actual soil requirements may vary based on plant type, soil compaction, and environmental conditions. Always check with a gardening expert if unsure.
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