A cubic metre of logs: loose, bagged and stacked

A cubic metre is simply volume: 1 m × 1 m × 1 m. The argument starts when one seller means a loose-filled container, another quotes a bag's outer dimensions and a store maker means a perfectly filled internal box.

Three different claims

Loose volume includes the random voids around tipped logs. It describes the container or load before stacking.

Stacked volume includes the smaller, regular gaps within a hand-built stack. It is the useful figure for sizing a store.

Solid wood volume excludes air gaps. Domestic firewood buyers rarely need it, but it explains why neither loose nor stacked volume equals the physical timber alone.

There is no honest universal conversion for every load. Short, straight split logs settle differently from long, crooked rounds. Mechanical tipping differs from hand filling. Treat any single multiplier as an estimate tied to a stated method.

Measure after stacking

Use the calculator above on the rectangular space occupied by the logs. Take an average height rather than measuring the tallest peak. If the stack is noticeably irregular, split it into two or three rectangles and add their volumes.

For example, a main block 1.5 m × 1.2 m × 0.45 m is 0.81 m³. A smaller block alongside it measuring 0.6 m × 0.7 m × 0.45 m is 0.19 m³. Together they occupy about 1.00 m³ stacked.

Ask better questions at delivery

Before buying, ask:

• Is the quoted figure loose or stacked?
• What are the filled bag or container dimensions?
• What log length is supplied?
• Can the delivery be left where it can be stacked promptly?

The answer “one builders' bag” is not enough. Builders' bags vary, and the way a flexible bag bulges makes outside measurements approximate.

Sources

• GOV.UK guidance on selling wood for domestic use in England — official sale-volume thresholds, checked 10 November 2026.
• Forest Research: Wood as fuel — background on firewood and energy by volume, checked 10 November 2026.