How big is a bulk bag of logs?

If you’ve ever tried to compare “bulk bags,” “builders’ bags,” and “ton bags,” you’ll know the sizes and claims can be confusing. This guide cuts through the noise with clear UK-specific dimensions, real-world capacity (loose vs stacked), rough log counts, weight expectations, and how long a bag typically lasts—so you can choose the right size with confidence.

The typical sizes of bulk bags on the UK market:

Standard bulk/builder’s bag (“ton bag”): typically 85 × 85 × 85 cm (about 0.61 m³ loose-filled).
Large bulk bag: often 90 × 90 × 90 cm (about 0.73 m³ loose-filled).
Small/half bulk bag: commonly 80 × 80 × 80 cm (about 0.51 m³ loose-filled).
Jumbo (less common for logs): 100 × 100 × 100 cm (about 1.00 m³ loose-filled).

Important: Bulk bags are loose-filled. If you compare to neatly stacked firewood (e.g., a “stacked cubic metre”), account for air gaps. A good rule of thumb is that 0.60–0.70 of a loose-filled volume equals the same wood neatly stacked.

Why the term “ton bag” is misleading

“Ton bag” refers to the bag’s lifting strength, not the confirmed weight of the firewood. Kiln-dried hardwood in a standard bulk bag will not weigh a tonne. Expect ~200–300 kg for kiln-dried hardwood in an 85×85×85 cm bag (species and split size affect this).

Typical UK bulk bag sizes (with practical equivalents)

Common name	Typical external dimensions (cm)	Loose volume (m³)	Approx. stacked-wood equivalent (m³)*	Typical rough log count**
Small / Half bulk bag	80 × 80 × 80	0.51	0.31–0.36	160–260
Standard bulk/builder’s (“ton bag”)	85 × 85 × 85	0.61	0.37–0.43	200–320
Large bulk bag	90 × 90 × 90	0.73	0.44–0.51	240–380
Jumbo FIBC (less common for logs)	100 × 100 × 100	1.00	0.60–0.70	350–520

* Uses a loose-to-stacked conversion factor of 0.60–0.70 (typical range).
** Based on ~25 cm log length and a mixed split size. Smaller splits increase the count; larger splits reduce it.

Bulk bag vs ‘stacked cubic metre’ getting an apples-to-apples comparison

Suppliers sometimes advertise crates or stacks by stacked m³ and bags by loose m³. To compare:

Loose 0.61 m³ (standard 85×85×85) ≈ 0.37–0.43 m³ stacked.
Loose 0.73 m³ (large 90×90×90) ≈ 0.44–0.51 m³ stacked.

If you’re choosing between a crate sold as 1.0 m³ stacked and a bag sold as 0.73 m³ loose, the crate contains more wood overall.

How many fires will a bulk bag cover?

It depends on your stove, the weather, and your burn style, but this is a useful planning guide:

Standard 0.61 m³ loose bag:
- If you typically burn 3–5 logs per hour, expect roughly 40–100 hours of active burning.
Large 0.73 m³ loose bag:
- Plan for 50–120 hours at similar burn rates.

Cold snaps, oversized rooms, and running your stove “hard” will shorten these estimates; shoulder-season top-ups will lengthen them.

Log length, split size, and stove compatibility

25 cm (10″) is the most common UK log length and fits the majority of modern stoves.
Smaller splits ignite faster and are great for quick heat response; larger splits offer longer, slower burns.
If your firebox is compact or unusually shaped, check the maximum recommended log length in your stove manual before ordering.

Moisture content: why kiln-dried <20% wins

Choose Ready to Burn-certified kiln-dried logs (moisture content ≤20%) to get:

Quicker ignition and hotter, cleaner burns
Less tar/soot in the flue (helps keep glass and chimney cleaner)
Higher efficiency and better value per bag burned

Seasoned logs can be excellent, but quality varies—especially in winter—so kiln-dried is the consistent, hassle-free option.

Species matter: heat, flame picture, and aroma

Oak/Beech/Hornbeam (dense hardwoods): long, steady heat; great overnight top-ups (in larger stoves).
Ash/Birch: bright flame, easy lighting, lovely flame picture; burn a bit faster than very dense species.
Mixed hardwood bags offer a balanced experience (easy lighting + solid heat).

Delivery reality check (and where a bulk bag will fit)

Most online suppliers deliver bulk bags on a pallet via tail-lift and pallet truck (kerbside). Practical tips:

Space needed: the bag’s footprint (e.g., ~0.75 m² for an 85×85 bag) plus turning room for the pallet truck.
Surface: firm, flat, and free of gravel; pallet trucks don’t roll on soft ground.
Access: check width restrictions, slopes, and dropped kerbs.
Storage: allow airflow; keep raised off bare ground; cover the top, not the sides. A garage with good airflow is ideal.

Some local suppliers crane-off loose bags without pallets, but national delivery is usually palletised.

Weight expectations (so you’re not surprised)

Approximate kiln-dried hardwood weights (species and split size vary):

Small/half bag (0.51 m³ loose): ~160–240 kg
Standard bag (0.61 m³ loose): ~200–300 kg
Large bag (0.73 m³ loose): ~240–360 kg

These are guides, not guarantees. Wood is a natural product and densities vary.

Bulk bag vs barrow bag vs crate—when to pick which

Barrow bag (~0.20–0.25 m³ loose):
- Best for tight access (through side gates/paths), top-ups, and occasional burners.
Bulk bag (0.51–0.73 m³ loose typical):
- The UK sweet spot for regular burners who want value, convenience, and easy handling.
Crate (stacked m³):
- Best £/m³ on dense hardwood and neat stacking; ideal for high-use homes or if you want a ready-made tidy stack.

Frequently Asked Questions

Q: Is a 90×90×90 cm bag worth the upgrade over 85×85×85?

Yes if you burn regularly. You gain roughly 20% more loose volume (0.73 m³ vs 0.61 m³).

Q: How do I compare two suppliers fairly?

Confirm external bag dimensions, 2) check whether the volume is loose or stacked, 3) verify log length (typically 25 cm), and 4) ensure moisture ≤20% (Ready to Burn).

Q: Will a standard bulk bag fit in a small shed?

If you can spare ~1 m² of floor space with some breathing room and dry airflow, yes.

Q: Can I tip a bulk bag into a log store?

If the bag is pallet-delivered, you’ll typically hand-stack. Plan 15–30 minutes for a standard bag (quicker with help).

How to size your order (a simple planning method)

Estimate hours you burn each week (e.g., 20 hours in winter).
Estimate logs per hour (e.g., 3–5).
A standard bulk bag holds ~200–320 logs → that’s ~40–100 hours of burning.
Decide how much buffer you want (bad weather, holidays, guests) and round up to the next bag size if you prefer certainty.

Common pitfalls to avoid

Comparing loose vs stacked volumes directly without converting.
Assuming “ton bag” = a tonne of wood (it doesn’t).
Ignoring access (pallet trucks can’t cross gravel or steep slopes).
Buying long logs that don’t fit your stove (25 cm is the safe bet for most UK appliances).

The bottom line

A standard UK bulk bag is typically 85 × 85 × 85 cm (≈0.61 m³ loose).
A large bulk bag is 90 × 90 × 90 cm (≈0.73 m³ loose).
To compare to neatly stacked volumes, multiply loose volume by ~0.60–0.70.
Expect ~200–320 logs in a standard bag of 25 cm kiln-dried hardwood, and ~240–380 in a large bag.
Choose kiln-dried, ≤20% moisture, for best heat, clean glass and happier chimneys.

Explore Bulk Bags of Kiln-Dried Logs at FirewoodFund

If you’re looking for consistent, Ready to Burn-certified hardwood in sensible UK-friendly sizes, our bulk bags are curated for easy delivery, reliable heat, and real value. Choose your bag size, log length, and species mix to match your stove and your burn style—then relax and enjoy the warmth. When you’re ready, browse our bulk bags and pick the perfect fit for your home.