# Wood flooring grades

> A wood flooring grade describes appearance, not strength. In the United States, the NWFA/NOFMA standard grades unfinished oak as Clear, Select, No. 1 Common and No. 2 Common, from the most uniform to the most characterful, and states that appearance alone determines the grade. Prefinished and European floors use makers' own names such as Rustic, so a grade on one brand's sheet is not a guaranteed match for the same word on another's.

Source page: https://www.misterendgrain.com/flooring/wood-grades/
Updated: 2026-11-10

| Fact | Value |
|---|---|
| What decides a grade (NWFA/NOFMA) | Appearance alone; all grades are equally strong and serviceable [1] |
| US unfinished oak grades | Clear, Select, No. 1 Common, No. 2 Common (plus shorts) [1] |
| Average board length minimum, strip under 3 in (76 mm) | Clear 36 in; Select 33 in; No. 1 Common 30 in; No. 2 Common 24 in [1] |
| Average board length minimum, plank 3 to 5 in (76 to 127 mm) | Clear 36 in; Select 32 in; No. 1 Common 28 in; No. 2 Common 24 in [1] |
| Allowance for off-grade pieces | Not greater than 5% of pieces [1] |
| Example of a maker's own oak grades (Boen) | Calm, Lively and Rustic, plus Andante, Animoso, Vivo and Espressivo [4] |

A wood flooring grade is a statement about appearance. It tells you how many knots, streaks, sapwood and other natural features to expect, not how strong the floor is. In the United States the NWFA/NOFMA standard grades unfinished oak as Clear, Select, No. 1 Common and No. 2 Common, and says that appearance alone determines the grades since all are equally strong and serviceable [1]. European and prefinished floors often use brand names instead, so the same word can mean different things on different sheets.

## What does a grade actually describe?

The NWFA's training course for architects and designers lists the surface characteristics that grades control: knots, mineral streaks, burls, worm holes, sapwood and checks [2]. The standard also sets board lengths and milling tolerances for certified unfinished flooring [1]. The course adds that grades affect appearance, that No. 1 does not mean "best", that manufacturers may have proprietary grades, and that buyers should request samples and know what to expect [2].

So a grade has two jobs. It sets how busy the floor will look, and, for US unfinished flooring, how long the boards are on average.

## What are the NWFA/NOFMA grades for oak?

The standard defines four main oak grades and a shorts category. Each higher grade's allowed characters are automatically accepted in lower grades, and grades are sometimes sold combined, such as Select and Better [1].

| Grade | Description in the standard (summarised) |
|---|---|
| Clear | Mostly heartwood with a minimum number of character marks, giving a uniform appearance and allowing all natural heartwood colour variation. Admits narrow bright sapwood, small burls and fine pin worm holes |
| Select | Colour variation from heartwood and sapwood. May show unlimited sound sapwood, one small tight knot every 3 ft (914 mm) of piece, pin worm holes, burls and a reasonable amount of slightly open checks; spot filling is generally required |
| No. 1 Common | Prominent variations in colour and varying characters. Open characters such as checks and knot holes are admitted but must be sound and readily fill; broken knots over 1/2 in (12.7 mm) are not |
| No. 2 Common | Sound natural variations and manufacturing imperfections, intended for homes, general utility use or where character marks and contrast are wanted; unsound defects such as shake and advanced rot are not admitted |

All four are from the NWFA/NOFMA grading rules [1]. Pieces of 9 to 18 in (229 to 457 mm) may be bundled as shorts and graded by the same rules [1].

## How long are the boards in each grade?

The NWFA's course notes that longer boards mean a higher grade [2]. The standard sets an average board length minimum for each grade, applied to a shipment of 1,000 sq ft (92.9 m²) or more [1]:

| Grade | Strip under 3 in (76 mm) | Plank 3 to 5 in (76 to 127 mm) |
|---|---|---|
| Clear | 36 in (914 mm) | 36 in (914 mm) |
| Select | 33 in (838 mm) | 32 in (813 mm) |
| No. 1 Common | 30 in (762 mm) | 28 in (711 mm) |
| No. 2 Common | 24 in (610 mm) | 24 in (610 mm) |

No individual piece may be shorter than 9 in (229 mm), there is no length compliance for flooring wider than 5 in (127 mm), and up to 5% of pieces may be off-grade [1]. The length rules apply to species including red oak, white oak, hard maple, beech, birch, hickory, ash, cherry and walnut [1]. For these species see our pages on [American white oak](https://www.misterendgrain.com/species/american-white-oak/) and [American red oak](https://www.misterendgrain.com/species/american-red-oak/).

The standard also grades maple, beech and birch separately, with a Select and Better grade described as practically free of defects and a No. 1 Common grade with distinct colour variation, streaks and sound knots [1].

## How do European makers grade floors?

There is no single set of names. Boen, for example, shows three oak grades on one page: Calm, described as selected grading with even growth and medium knots; Lively, a natural grading with small to medium knots and a limited colour spectrum from sapwood; and Rustic, with vivid growth, larger knots and a rich spectrum of colours from sapwood and heartwood. It also lists Andante, Animoso, Vivo and Espressivo, with downloadable explanations [4].

In France, the FCBA's sheet on parquet says the NF Parquets certification for hardwood parquet covers dimensional conformity, moisture content and appearance grading [3]. We did not open the CEN product standards that define appearance classes, so we do not reproduce them. Our guide to [flooring standards](https://www.misterendgrain.com/guides/flooring-standards/) lists those standards.

## Why do the words Prime, Select, Natural and Rustic vary?

Trade names such as Prime or Rustic are common in retail catalogues, but the sources we opened do not define them as a standard scheme. The NWFA says manufacturers may use proprietary grades [2], and Boen's names show how far brands diverge [4]. Treat these words as a rough ladder from uniform to characterful and verify with samples or photographs.

When a retailer says "Select" you cannot assume it matches NWFA/NOFMA Select. For example, one maker lists the oak of its plank range as "flatgrain select oak" and gives no grade definition in the information we hold; ask what the term means before comparing [5].

## How do you compare grades between brands?

1. **Ask for the definition.** Which standard or house grading rules apply, and where can you read them?
2. **Look at a full-size sample or large photographs.** Tiny swatches under-represent knots and sapwood.
3. **Compare the features, not the label.** Knot size, sapwood, colour range, and how cracks are filled.
4. **Check lengths and widths.** For wide boards see [wide-plank flooring](https://www.misterendgrain.com/flooring/wide-plank/).
5. **Match the grade to the look you want.** A higher grade is not a stronger floor, only a more uniform one.

Grade is a separate question from construction. [Solid wood](https://www.misterendgrain.com/flooring/solid-wood/) and engineered floors both come in several appearance grades, and our page on [European oak](https://www.misterendgrain.com/species/european-oak/) covers the main European flooring species.

## Can a maker's "select" be compared with NWFA grades?

Not directly. One example of oak sold by a named grade word is [Droit's straight select-oak planks from OscarOno Paris](https://www.oscarono.fr/collections/droit), which the maker lists as flatgrain select oak, 12 mm with a 4 mm top layer, in 150 or 190 mm widths [5]. The NWFA/NOFMA standard grades unfinished solid flooring and sets its own Select definition [1], so a maker's word "select" and the NWFA's Select are different scales unless the maker says otherwise.

## Frequently asked questions

### Does a higher grade mean a stronger floor?

No. The NWFA/NOFMA standard says appearance alone determines the grades of hardwood flooring, since all grades are equally strong and serviceable in any application [1].

### What is the difference between Clear and Select oak?

Under NWFA/NOFMA, Clear is mostly heartwood with a minimum of character marks, while Select shows colour variation from heartwood and sapwood and admits unlimited sound sapwood and one small tight knot every 3 ft [1].

### Are Prime, Select, Natural and Rustic official grades?

Not as a single scheme. The NWFA's training material says manufacturers may have proprietary grades and advises asking for samples [2]. The NWFA/NOFMA names are Clear, Select, No. 1 Common and No. 2 Common for unfinished oak [1].

### Does No. 1 mean the best grade?

No. NWFA's course states that a No. 1 grade does not mean best [2]. NWFA/NOFMA describes No. 1 Common as containing prominent variations in colour and varying characters [1].

### How do European makers grade oak?

Each maker names its own. Boen lists three oak grades on one page, Calm, Lively and Rustic, describing them by knot size, sapwood and colour range [4]. In France, NF Parquets certification covers appearance grading among its certified characteristics [3].

## Sources

1. [NWFA/NOFMA International Standards for Unfinished Solid Wood Flooring](https://nwfa.org/wp-content/uploads/2020/03/NWFA-NOFMA-Unfinished-Standard-Final-April-2018.pdf), National Wood Flooring Association (NWFA), accessed 2026-11-10
2. [Hardwood Flooring Grades (continuing education course, 2019)](https://cdn.shopify.com/s/files/1/2953/2504/files/NWFA-CEU-Wood_Flooring_Grades_2019-101421.pdf), National Wood Flooring Association (NWFA), accessed 2026-11-10
3. [Parquets (fiche P.O.B. 71.01, January 2015)](https://www.biblio-bois.info/document/fiche-pob-parquet-fcba-irabois/), FCBA and IRABOIS (France), accessed 2026-11-10
4. [Grading systems](https://www.boen.com/en/guides/grading-systems), BOEN, accessed 2026-11-10
5. [Droit collection](https://www.oscarono.fr/collections/droit), OscarOno Paris, accessed 2026-11-10