Enter nonnegative side lengths in meters.
One cubic meter is exactly 1,000 liters. From the exact international-foot definition, 1 m³ = 1 ÷ 0.3048³ = 35.314666721488… ft³. From the defined U.S. liquid gallon, 1 m³ = 1,000 ÷ 3.785411784 = 264.172052358148… US gal.
For 2 m × 1.5 m × 1 m, the result is 3 m³, 3,000 L, about 105.944 ft³, and 792.516 US gal. Inputs producing an invalid numeric result are rejected.
Related: the cubic feet calculator for the imperial counterpart, the cubic feet to cubic meters converter to convert an existing ft³ value to m³, and the l to gal converter for the liter–gallon relationship.
Use one dimension basis for the whole object
Convert every measured side to meters before entering the rectangular-volume form. Keep interior and exterior measurements separate; mixing them can describe no actual container. If you have several pieces, retain each piece’s volume as a subtotal rather than adding lengths and treating them as one rectangular object.
Combine pieces by volume
For multiple rectangular pieces, calculate each piece using its own meter dimensions and retain a subtotal list. Add the volumes afterward. Adding the lengths, widths, and heights first describes a different rectangular solid, not the collection of pieces.
Keep any material-purchase allowance separate from the geometric total. This makes it possible to revise one measurement without losing which part of the order came from the measured project and which came from an allowance.
Sources
- NIST, Guide for the Use of the International System of Units (SP 811) — SI units and accepted conversion guidance.
- NIST, Handbook 44, Appendix C — U.S. customary volume and length relationships used for dimensional arithmetic.