Measure · choose your parts · plan a batch

Your mix, measured

Turn a volume and your own component ratios into a batch worksheet, with optional package counts and leftovers.

Planning only. The editable A/B/C example is arithmetic, not a recipe or recommendation.

Use plain numbers with a dot decimal (up to 6 places). No commas, grouping, signs or scientific notation. All qt and gal units here are US liquid measures, not US dry or Imperial. Check package labeling; use liters when in doubt. Changing a unit reinterprets the entered number.

1. Volume per pot or batch

Measure inside the pot. Round uses diameter; ellipse uses full length and width. This estimates a straight-sided volume, not the exact capacity of a tapered pot.

2. Your planning adjustments

Choose 0–100% for each. First multiply volume by quantity, then subtract your occupied/unused allowance, then add margin. Leave both at 0% to keep the base volume. For known net substrate volume, avoid subtracting occupied space twice.

3. Components you choose

Use 2–5 components. Positive parts need not add to 100: 2 / 1 / 1 means 50% / 25% / 25%. Names are optional (60 characters maximum). Package sizes are optional and must be positive; leave empty to skip.

Real needs vary with root mass, taper and irregularity, drainage screens, tie-downs, mounding, compaction and settling, particle grading, watering, climate and species. Measure internal dimensions and add contingency only if desired. This worksheet does not predict drainage, root health, particle size, watering needs or repotting timing.

Your entries stay in this browser tab. Nothing is saved or sent by the calculator. Copy and print happen only when you choose them.

Method, units and limits

Rectangle: length × width × depth. Round: π × (diameter ÷ 2)² × depth. Ellipse: π × (length ÷ 2) × (width ÷ 2) × depth. π is fixed at 3.141592653589793.

Base = one volume × quantity. Adjusted = base × (1 − unused% ÷ 100). Total = adjusted × (1 + margin% ÷ 100). Each component receives total × its parts ÷ sum of parts. Packages round required volume ÷ package volume up to a whole number; leftover = packages × package volume − required volume.

1 in = 25.4 mm; 1 L = 1,000,000 mm³; 1 US liquid gal = 3.785411784 L; 1 US liquid qt = 0.946352946 L; 1 cu in = 16.387064 mL, all exactly.

Limits: quantity 1–10,000; internal dimensions 0.001–10,000 mm after conversion; one pot/batch up to 10,000 L; base and final totals up to 1,000,000 L. Known volume may be zero. Parts 0.000001–1,000,000 each; packages 0.000001–10,000 L, up to 1,000,000,000 packages per component. These are arithmetic guardrails, not horticultural guidance.

References: NIST SI conversion guide, NIST Handbook 44, and Wolfram MathWorld on the cuboid, cylinder and ellipse.

Plan your next step

These guides provide context for your own observations. Mix suitability, particle size, watering, and repotting timing depend on the species, tree condition, pot, and growing conditions; a volume worksheet cannot settle those choices.