Random Length Timber Explained

Random-length timber is easy to misunderstand because the word “random” sounds as though nothing has been specified. In a proper order, plenty should still be specified: species, grade, thickness, finish, quantity, permitted length range and any minimum length the job genuinely needs.

What remains variable is the length of the individual boards within that agreement. One board may be 2.1 m, another 2.7 m and another 3.4 m. Depending on the product, the widths may vary as well.

This guide explains what random length normally means, the different ways suppliers use the term, how mixed boards are measured and charged, and how to decide whether an offer suits the cutting list. How Timber Lengths Are Sold explains the wider difference between fixed, stock, cut and random lengths. How Much Timber Do I Need covers the full cutting calculation.

1. The short answer

Random-length timber is a quantity of boards whose individual lengths are not all identical. The boards may fall within a stated range, be offered as a mixed parcel, or be selected from the supplier’s current stock.

The term does not by itself tell you:

• the shortest or longest board;
• the average length;
• how many boards fall into each part of the range;
• whether you may choose individual boards;
• whether widths are fixed or random as well;
• whether the quantity is measured in linear metres, square metres, cubic metres, cubic feet or board feet;
• whether you must buy whole boards or a complete pack;
• whether a particular proportion will yield your longest components.

Those are commercial terms to confirm, not details hidden inside the word “random”.

Random length describes variation between boards. It is not a complete specification of the parcel.

2. Random does not mean defective or offcut

A sound full board can be random length. The term describes its dimension within the parcel, not its grade, condition or origin.

Random-length stock is not automatically:

• short offcuts;
• an unsorted clearance bundle;
• lower grade;
• inaccurately measured;
• a promise of equal numbers of short and long boards;
• a guarantee that every length in the advertised range will be present.

Grade and length are separate parts of the description. A parcel can be high-grade timber in mixed lengths, or lower-grade timber in fixed lengths. It can also meet the stated grade while containing natural features that affect a particular cutting plan.

If a listing says only “random lengths”, ask for the range and the basis of sale before deciding whether it is suitable.

3. Why timber is offered this way

Trees do not produce a uniform series of clear rectangular blanks. Logs differ in length, diameter, taper, sweep and defects. The useful boards recovered from them therefore differ too. A sawmill or importer can preserve more usable material by producing and trading a range of boards rather than trimming every sound piece down to one arbitrary length.

The practice is particularly familiar in hardwood. American hardwood grading and measurement rules were developed for random-width and random-length lumber. AHEC advises buyers to discuss any selection for particular dimensions before ordering rather than assuming those dimensions are included in the normal grade.

Random-length selling can therefore:

• improve recovery from the log;
• keep useful longer and shorter boards in circulation;
• make broadly specified stock more available;
• allow a user with a varied cutting list to obtain good yield;
• cost less than asking a supplier to sort or manufacture one exact length.

That does not make it the right offer for every job. The system works best when the buyer can use a genuine mixture.

4. The term covers several different products

“Random length” can describe quite different offers. Treat the supplier’s wording as the starting point, then establish what it means for that product.

Offer	What may vary	What to confirm
Rough-sawn hardwood boards	Length and often width	Actual tally, minimum dimensions, whole-board policy and grade
Square-edged hardwood pack	Length, width or both	Pack range, average width, volume and permitted short boards
PAR or moulded section	Length only; section is fixed	Length range, metre quantity, full-board charging and fixed-length option
Flooring or cladding	Board length within a pack	Minimum and maximum, distribution, pack coverage and installation pattern
Production pack	The mix supplied by the mill	Whether the pack can be split and whether the tally is available
Selected project order	Stock is mixed, but boards are picked to agreed needs	Selection charge, minimum order and the exact acceptance rule

For example, a current UK listing for planed meranti shows a price per metre but says the material will be supplied in random board lengths between 2.1 m and 5.1 m; fixed lengths are a separate branch enquiry. A current European oak pack offer instead specifies a volume, mixed widths and one of two broad length groups.

Both are random-length offers, but they cannot be ordered or checked in the same way.

5. A range is not a distribution

Suppose an offer says 2.1–4.8 m random lengths. That establishes outer limits only if the wording is intended as a firm range. It does not say how the order will be distributed between them.

A 20 m order might contain many boards near 2.1 m, several near 3 m or a few longer boards. It need not contain a balanced mixture, and it need not contain a 4.8 m board merely because 4.8 m is the top of the range.

If the distribution matters, convert the requirement into something observable. Depending on the job, that might be:

• no board shorter than 2.4 m;
• at least four boards with 2,200 mm of continuous usable length;
• at least 30% of the supplied linear metres in lengths of 3.0 m or more;
• one unbroken piece capable of finishing at 3,600 mm;
• a tally for approval before dispatch.

Do not ask for an average when the job depends on a minimum. An average of 2.8 m can be made from many different and commercially significant mixtures.

A stated range tells you what may arrive. A cutting list tells you what must arrive.

6. Random length and random width are separate

Rough-sawn hardwood is often sold in random widths as well as varied lengths. A pack may have one nominal thickness while every board has its own width and length.

The order therefore has three independent dimensions:

Dimension	Possible basis
Thickness	One nominal sawn thickness or one finished thickness
Width	Fixed, minimum, mixed, random or waney-edged
Length	Fixed, minimum, ranged, mixed or random

Do not use “random boards” as shorthand for all three. A supplier might offer random-width oak at a fixed 2.1 m-and-longer length condition, or a fixed PAR section in random lengths.

Where boards are random width, a total linear-metre figure is especially weak. Ten linear metres of 100 mm-wide boards contains half the face area and half the volume of ten linear metres at 200 mm wide, assuming equal thickness.

For mixed-width sawn boards, compare the measured area or volume and then check whether the individual boards can yield the required components. Buying Timber by the Linear Metre, Square Metre and Cubic Metre explains those units.

7. What a tally is

A tally is a record of the timber being counted or measured for the transaction. For a mixed parcel it may list each board’s length and width, its calculated area or volume, or group identical dimensions together.

The word does not guarantee one universal measuring convention. Imported American hardwood may be tallied under NHLA and board-foot rules. British-grown hardwood may be measured in metric units using a supplier’s stated practice. Machined sections may simply be totalled in linear metres.

A useful tally for a small project shows enough to answer:

• How many boards are supplied?
• What are their individual or grouped lengths?
• What widths apply if the boards are not fixed width?
• Which thickness is being charged: nominal sawn or finished?
• What rounding convention has been used?
• What total quantity appears on the invoice?

AHEC’s explanation of an export bundle tally is a good example of why the measuring convention matters. Under that system, random board widths are rounded to whole inches according to the stated rules, while a length between whole-foot increments is tallied down to the nearest whole foot. That is not permission to apply the same rounding to every UK merchant order. It is a reminder to ask which system produced the number.

8. How random lengths may be charged

The boards can vary in length while the price is expressed in several different units.

Pricing basis	What the bill normally depends on	What remains to check
Per linear metre	Total supplied length at a fixed section	Minimum order, whole-board policy and actual mix
Per square metre	Covered or measured face area	Whether width is actual, nominal or installed cover
Per cubic metre or cubic foot	Measured volume	Nominal versus actual dimensions and tally method
Per board foot	Imperial hardwood volume convention	Thickness and tally rules
Per board	Each selected piece	Actual board dimensions and whether selection is included
Per pack	The declared bundle	Tally, range, volume and whether the pack can be split

A rate per metre does not necessarily allow you to order an arbitrary cut length. A merchant may total the complete boards needed to reach the requested metre quantity. The supplied total may therefore exceed the number typed into an online quantity box.

Likewise, a cubic-metre price does not make every cubic metre equally useful for a particular project. Volume is the charging quantity; cutting yield is the project quantity.

Ask whether the invoice will use the requested quantity, the actual tally, a pack quantity or a permitted over-supply tolerance.

9. Selection changes the offer

The standard random mix may be economical because the supplier can use the stock as it stands. Asking for only long boards, only wide boards, a narrow colour range or a particular grain pattern removes some of that flexibility.

A supplier may respond by:

• selecting from the pack and charging for the service;
• applying a fixed-length or specification premium;
• increasing the minimum order;
• offering a different grade or species;
• asking you to accept the boards left after selection;
• declining because the remaining stock would become difficult to sell.

That is not evidence that the original random offer was poor. It is a different product. AHEC notes that producers can sort for specified lengths, widths and grain patterns where buyer and seller agree the terms.

State only the constraints the job actually needs. If a 2,400 mm component can be made from a board with 2,450 mm of usable length, do not automatically demand every board at 3.0 m or longer.

10. Whole boards, part boards and pack quantities

Many hardwood merchants prefer to sell the whole board selected. Some will sell part of a board but apply a surcharge or refuse a cut that leaves an unsaleable remainder. Pack products may have a minimum volume and may not be split at all.

Before choosing boards, ask:

• Must each selected board be bought whole?
• Will the merchant cross-cut a board for transport?
• If it is cut, am I charged for and given both pieces?
• Can a part board be bought, and is there a surcharge?
• Is there a minimum volume, metre quantity or order value?
• Can a production pack be broken?

One UK hardwood merchant currently explains that its sawn stock is normally bought as the board stands. It may sell part boards, sometimes with a surcharge, but will not make a cut that leaves it with a piece below its stated resale dimensions. That is a merchant policy, not a rule for the whole trade, but it shows why the question belongs before the saw cut.

11. Total quantity does not prove cutting yield

Consider two theoretical parcels of the same fixed section. Each contains 12.0 linear metres:

Parcel A	Parcel B
2.1 m	3.0 m
2.1 m	3.0 m
2.4 m	3.0 m
2.7 m	3.0 m
2.7 m
Total: 12.0 m	Total: 12.0 m

If the project needs four continuous pieces finishing at 2.2 m, Parcel A has only three boards long enough before any end trimming or defects are considered. Parcel B has four.

The total linear metres are identical. The useful yield for that cutting list is not.

For random-width boards, the calculation is one step harder. Each required component must fit within both the usable length and usable width, with allowance for saw kerfs, straightening, planing, defects, grain direction and any matching requirement.

This is why a blanket waste percentage cannot rescue a badly specified length mix. Extra volume made up of boards that are all too short for the critical component is still the wrong stock.

12. Work from the critical components first

Separate the cutting list into three groups:

1. Critical long pieces that must come from one continuous board.
2. Repeated medium pieces whose arrangement determines most of the yield.
3. Short pieces that can use sound material around defects or the ends of longer cuts.

Use the long pieces to set the minimum board requirement. Then test whether the remaining material can produce the medium and short components.

Do not assume that one nominal board length equals one usable component of the same length. Allow for whatever the job requires, which may include:

• cleaning or squaring the ends;
• saw kerfs;
• removing end checks, wane or damage;
• straightening a bowed or sprung board;
• planing to finished thickness;
• ripping a straight edge;
• avoiding a feature that is permitted by the grade but not by the component;
• matching colour or grain across visible parts.

There is no honest universal allowance. The right margin depends on the product, grade, board condition and cutting plan.

13. When random lengths work well

Random lengths are often a good fit when:

• the cutting list contains a real mixture of long and short parts;
• shorter parts can be nested around natural features;
• the design can accommodate joints or varied board lengths;
• the buyer can inspect or work from a tally;
• the workshop has the machinery and time to break down rough stock;
• price and availability matter more than identical blank sizes;
• a full pack will be used across several jobs.

They are a poor fit when:

• every component needs nearly the maximum advertised length;
• one missing long board stops the entire job;
• the design needs repeated full-length boards with no joints;
• site access or machinery limits the maximum board length;
• the buyer expects a finished cut list rather than raw material;
• the order is too small to absorb a mixed parcel economically.

In those cases, ask for selected minimum lengths, fixed lengths or components cut to an agreed schedule. Compare the higher material or selection price with the labour and waste avoided.

14. A worked enquiry

Suppose a furniture job needs the following visible oak components after machining:

Component	Finished size	Quantity
Long rail	22 × 70 × 2,200 mm	4
Short rail	22 × 70 × 850 mm	8
Blocks	22 × 70 × 180 mm	12

The supplier has kiln-dried square-edged oak in a suitable grade and sawn thickness, sold by volume in mixed widths and lengths.

An incomplete enquiry would be:

Please quote enough random-length oak for these parts.

A more useful enquiry is:

Please quote kiln-dried square-edged European oak in the agreed grade and sawn thickness, sufficient to finish the attached cutting list at 22 mm. The order must include at least four boards with enough sound width to finish at 70 mm and at least 2,250 mm of continuous usable length after normal end trimming. Mixed widths and shorter boards are acceptable for the remaining parts. Please confirm the available length range, minimum board width, measured volume, whole-board or pack policy, permitted quantity variation and whether a board tally can be supplied before dispatch.

The extra 50 mm in that example is a project assumption, not a timber-trade standard. It must be increased, reduced or replaced after considering the actual boards, end condition, machining process and supplier’s advice.

15. What to put on the order

Record the following as applicable:

• Species:
• Grade and permitted features:
• Moisture condition:
• Sawn or finished thickness:
• Fixed, minimum or random width:
• Permitted length range:
• Minimum continuous usable lengths and quantities:
• Total quantity and pricing unit:
• Actual tally, pack quantity or permitted over-supply:
• Whole-board, part-board or full-pack sale:
• Selection or fixed-length premium:
• Certification or documentation required:
• Delivery, access and maximum handling length:

If no length distribution is important, say so. Flexibility can help the supplier offer better availability and value. If a minimum is critical, put it on the written order rather than relying on a telephone description of the usual pack.

16. Checking the delivery

Check the order against the agreed basis before cutting or machining it.

1. Count the boards or packs.
2. Compare the species, grade, thickness and finish with the order.
3. Check the shortest, longest and critical minimum lengths.
4. Compare the boards with the tally where one was supplied.
5. Confirm the width basis if boards are mixed or waney-edged.
6. Record unexpected damage, shortage or substitution with photographs.
7. Keep labels, tally sheets and delivery paperwork until the check is complete.

Do not reject a board merely because its length differs from another if mixed lengths were agreed. Equally, do not accept an unusable mix merely because its total volume is correct if the written order also required specific minimum lengths.

The agreement is the test.

17. Questions to ask before paying

1. What is the firm minimum and maximum board length?
2. Does that range describe every board, or only the stock generally available?
3. Are widths fixed, minimum or random as well?
4. May I select boards, or will the supplier choose the mix?
5. Can you guarantee the number or proportion above my critical minimum length?
6. Is a tally available before dispatch?
7. How is the quantity measured and rounded?
8. Am I buying whole boards, part boards or a complete pack?
9. Is the invoice based on the requested quantity or the actual quantity supplied?
10. Is there a premium or minimum order for selected or fixed lengths?
11. If boards are cut for delivery, do I receive and pay for both pieces?
12. What should I do if the delivered mix does not match the written order?

18. Quick reference

If an offer says…	Do not assume…	Confirm…
Random lengths	Any length on request	Firm range and selection method
2.1–4.8 m	A balanced mix or a 4.8 m board	Distribution or critical minimums
£ per metre	Cut-to-any-length service	Whole-board and over-supply policy
Random-width boards	One standard width	Minimum, average or actual tally
1 m³ pack	The right components will fit	Board dimensions and cutting yield
Selected lengths	Selection is included in the base rate	Premium, minimum order and acceptance rule
Tally supplied	Every merchant uses the same rules	Units, rounding and measured dimensions
Fixed lengths available	They are in ordinary stock	Lead time, price and quantity

Buy the mixture that fits the cutting list, not merely the total quantity that fits the calculator.

Where these numbers come from

The explanation of American random-width and random-length hardwood, board-foot measurement and export bundle tallies comes from the American Hardwood Export Council’s guide to NHLA measurement. Its tally example is identified as an American export convention, not presented as a universal UK invoicing rule.

The distinction between normal random stock and separately agreed dimensional selection is also supported by AHEC’s sourcing and grading guidance, which tells buyers to discuss particular specifications before ordering and describes additional sorting by length, width and grain pattern.

The current UK examples demonstrate why “random length” needs a product-specific definition. Builder Depot lists a fixed-section PAR meranti product priced per metre and supplied in random lengths from 2.1 m to 5.1 m. UK Timber’s European oak pack builder sells measured volumes of mixed-width boards in broad length groups and states the expected shorter-board allowance. iWood’s European oak pack builder shows a different pack specification based on grade, thickness, selected length category, volume and an average-width condition. Illingworth Ingham describes cubic-metre PAR packs as generally random length while offering packaged-to-length stock by discussion.

The whole-board example comes from Richard Potter Timber’s published hardwood policy. Its specific minimum remainder and surcharge terms are not generalised beyond that merchant.

All cutting lists and parcels in the worked examples are illustrative. The 50 mm extra length is explicitly a project assumption, not a recommended universal trimming allowance.

Technical references

• American Hardwood Export Council: measurement and random-length lumber
• American Hardwood Export Council: additional grading guidance
• American Hardwood Export Council: sourcing American hardwood
• Builder Depot: PAR meranti supplied in random lengths
• UK Timber: kiln-dried European oak pack builder
• iWood: European oak pack builder
• Illingworth Ingham: random-length PAR packs
• Richard Potter Timber: hardwood sizes and whole-board policy

Related

• Timber Buying Guides
• How Much Timber Do I Need
• Buying Timber by the Linear Metre, Square Metre and Cubic Metre
• How Timber Lengths Are Sold