Choose 5052-H32 when
the plate will be bent, exposed to sea air or welded into a tank. It forms with tight radii that would crack 6061-T6, and it is usually the lowest-cost strong grade at this thickness.
Plate guide
1/4 Inch Aluminium Plate: Sizes, Weight and Grade Selection
A 1/4 inch aluminium plate is 0.250 in or 6.35 mm thick and weighs about 3.5 lb per square foot (17.1 kg/m²) in 6061, so a 4 × 8 ft sheet comes to roughly 112 lb or 51 kg. It is the thinnest gauge that ASTM classes as plate rather than sheet, and it is ordered most often in 5052-H32, 6061-T651 and 7075-T651. This guide gives the weights, grade choices, standards and buying checks in one place.
- Thickness
- 0.250 in = 6.35 mm
- Weight (6061)
- ≈ 3.51 lb/ft² · 17.1 kg/m²
- 4 × 8 ft sheet
- ≈ 112 lb / 51 kg
- Main grades
- 5052 · 6061 · 7075 · 5083
What does "1/4 inch aluminium plate" mean?
The name describes a thickness, not an alloy. One quarter of an inch is exactly 6.35 mm, because the international inch is defined as exactly 25.4 mm. Any aluminium grade can be rolled to this gauge; what the buyer still has to choose is the alloy, the temper and the sheet or cut size.
The quarter-inch gauge sits on an important boundary. Under ASTM B209 and the ANSI H35.2 dimensional tables used in North America, flat-rolled aluminium from 0.006 in up to 0.249 in is called sheet, and material 0.250 in and thicker is called plate. A 1/4 inch product is therefore the thinnest plate in the American system, and in practice it is sold by both sheet distributors and plate service centres. European standards draw the line at 6 mm (EN 485 and EN 12258 call products over 6 mm plate), so a 6.35 mm product is also plate in Europe, while the closest metric gauge, 6 mm, is technically still sheet.
This matters when you order. Plate tolerances, flatness rules and tempers such as T651 (stress-relieved by stretching) apply to 1/4 inch material, and mills often roll it on plate lines rather than sheet lines. If your drawing says 6 mm but your supplier offers 1/4 inch, or the other way round, the difference is 0.35 mm, about 6 % of the thickness and of the weight, which can affect fits, fastener lengths and freight cost.
Quick conversions
- 1/4 in
- 0.250 in · 6.35 mm
- Nearest metric plate
- 6 mm (0.236 in) or 6.5 mm (0.256 in)
- Neighbouring imperial gauges
- 3/16 in (4.76 mm) and 5/16 in (7.94 mm), 3/8 in (9.53 mm)
- Area of a 4 × 8 ft sheet
- 32 ft² · 2.973 m²
Where 1/4 inch sits in the thickness range
Different industries use slightly different words for thickness bands. The table below shows the common trade terms alongside the standards definitions, so you can see why the same piece of metal may be called "heavy sheet" by one buyer and "light plate" by another.
| Band | Approximate range | Typical description |
|---|---|---|
| Foil | Below 0.2 mm (0.006 in) | Packaging, fin stock, insulation |
| Sheet | 0.2 – 6.3 mm (0.006 – 0.249 in) | Panels, enclosures, formed parts |
| Light plate | 6.35 – 12.7 mm (1/4 – 1/2 in) | Brackets, base plates, deck plate, tanks |
| Medium plate | 12.7 – 50 mm (1/2 – 2 in) | Machined parts, fixtures, structural plate |
| Thick plate | 50 – 200 mm (2 – 8 in) | Moulds, aerospace blocks, tooling |
Band names other than sheet and plate are trade usage, not standard definitions. The sheet/plate boundary follows ASTM B209 (0.250 in) and EN 485 (over 6 mm).
How much does 1/4 inch aluminium plate weigh?
Weight is thickness × width × length × density. At 6.35 mm, one square metre of plate holds 0.00635 m³ of metal; multiplied by the density of 6061 (2,700 kg/m³) that is 17.15 kg/m². In imperial units, one square foot of 1/4 inch plate is 36 in³, which at 0.0975 lb/in³ gives 3.51 lb/ft².
Alloy changes the answer by a few per cent, because magnesium makes aluminium lighter and zinc and copper make it heavier. The table uses Aluminum Association nominal densities.
| Alloy | Density (g/cm³) | kg per m² at 6.35 mm | lb per ft² at 0.250 in |
|---|---|---|---|
| 1100 | 2.71 | 17.21 | 3.53 |
| 3003 | 2.73 | 17.34 | 3.55 |
| 5052 | 2.68 | 17.02 | 3.48 |
| 5083 | 2.66 | 16.89 | 3.46 |
| 6061 | 2.70 | 17.14 | 3.51 |
| 7075 | 2.81 | 17.84 | 3.65 |
| 2024 | 2.78 | 17.65 | 3.60 |
Weights for the most common 6061 cut and stock sizes:
| Size | Weight (lb) | Weight (kg) |
|---|---|---|
| 12 × 12 in | 3.5 | 1.6 |
| 24 × 24 in | 14.0 | 6.4 |
| 48 × 96 in (4 × 8 ft) | 112.3 | 50.9 |
| 48 × 120 in (4 × 10 ft) | 140.4 | 63.7 |
| 48 × 144 in (4 × 12 ft) | 168.5 | 76.4 |
| 60 × 120 in (5 × 10 ft) | 175.5 | 79.6 |
| 60 × 144 in (5 × 12 ft) | 210.6 | 95.5 |
For any other size or alloy, use the aluminium plate weight calculator. Remember that freight is charged on gross weight, so add pallet or case weight when you estimate shipping.
Which alloy should you choose for 1/4 inch plate?
Most quarter-inch orders fall into four or five alloys. Pick by the job the plate has to do: forming and corrosion resistance point to the 5xxx series, machining and general structures to 6061, and high stress to 7075.
| Alloy and temper | Typical tensile / yield | Strengths | Typical 1/4 in uses |
|---|---|---|---|
| 3003-H14 | 150 / 145 MPa | Cheap, very formable, good corrosion resistance | Covers, ducting, tread plate (H22), general fabrication |
| 5052-H32 | 230 / 195 MPa | Bends well, excellent in salt air, weldable | Boat parts, fuel tanks, truck bodies, enclosures |
| 5083-H116 / H321 | 315 / 230 MPa (min. ≈ 305 / 215) | Highest non-heat-treatable strength, seawater rated | Hull plating, marine decks, pressure vessels |
| 6061-T651 | 310 / 276 MPa | Machines and welds well, anodises cleanly, stays flat | Machine plates, brackets, frames, fixtures |
| 7075-T651 | 572 / 503 MPa | Very high strength and fatigue resistance | Aerospace fittings, tooling, high-load parts |
| 2024-T351 | 470 / 325 MPa (typical, sheet/plate) | High strength with good fatigue and toughness | Aircraft skins and structure, defence |
Values are typical properties from Aluminum Association and ASM data. Design to the specified minimums in ASTM B209 or EN 485-2, which fall slightly below these figures.
Choose 6061-T651 when
the plate will be machined, drilled and tapped, or anodised. Stretching relieves quench stress, so pockets and slots do not make the plate bow.
Choose 7075-T651 when
strength-to-weight is the priority and the part will not be welded. Expect a higher price and plan to protect it from corrosion with anodising or paint.
Choose 5083 when
the plate is permanently in seawater or must be certified by a classification society for a hull or deck.
Choose tread plate when
you need a slip-resistant surface. 1/4 in diamond plate is usually 6061-T6 for strength or 3003-H22 for economy; the quoted thickness excludes the raised pattern on some mills, so check.
Choose cast tooling plate when
flatness and machining stability matter more than strength, for example in jig plates and vacuum tables.
Standards, tolerances and certificates for 1/4 inch plate
Quarter-inch plate is covered by the same standards as any other rolled aluminium plate. Quote the governing specification on your purchase order so that chemistry, tensile minimums and dimensional tolerances are all defined.
Common specifications
- ASTM B209 / ASME SB-209
- Sheet and plate, general and pressure-vessel use; tolerances per ANSI H35.2
- SAE AMS 4027 / AMS 4045 / AMS 4037
- Aerospace 6061-T651, 7075-T651 and 2024-T351 plate
- ASTM B928
- 5xxx marine plate (5083, 5086, 5456) with corrosion testing for H116 and H321
- EN 485-1 to -4 / EN 573-3
- European technical conditions, properties, tolerances and chemistry
- JIS H4000
- Japanese sheet and plate (A5052P, A6061P, A7075P)
- Certificate
- Mill test certificate to EN 10204 3.1 with heat number, chemistry and tensile results
Thickness, width, length and flatness tolerances depend on the alloy group, the width of the plate and whether it is supplied as mill-sheared, saw-cut or precision-milled. Standard mill tolerances are fine for most fabricated parts. If your design relies on a precise 6.35 mm, specify a tighter tolerance or machine the critical faces; if it relies on 6.0 mm, buy metric plate rather than assuming 1/4 inch will do.
Ordering 1/4 inch plate from Metline
- Define the plateAlloy and temper (for example 6061-T651), 1/4 in or 6.35 mm, sheet size or drawing, quantity and governing standard.
- Agree processingFull sheets, saw-cut blanks, waterjet or CNC profiles, PVC film on one or both faces.
- Confirm termsEXW, FOB, CIF or DAP, inspection requirements and certificate type (EN 10204 3.1 as standard).
- ShipPlates are interleaved, wrapped against moisture and packed on fumigated pallets or in wooden cases for sea or air freight.
What sets the price of 1/4 inch aluminium plate?
Aluminium plate is priced as metal plus conversion. The metal element follows the London Metal Exchange (LME) aluminium price plus a regional premium; the conversion element covers rolling, heat treatment, stretching, testing and packing, and it varies much more between alloys than the metal price does.
- Alloy and temper: 3003 and 5052 carry modest conversion charges; 6061-T651 more, because of solution treatment and stretching; 7075 and 2024 the most.
- Certification: aerospace plate under AMS specifications, with ultrasonic testing and full traceability, costs more than commercial ASTM B209 plate of the same alloy.
- Size and yield: cut pieces are priced on the plate they are cut from, so nesting parts efficiently on a 48 × 144 in or 1250 × 2500 mm sheet reduces cost.
- Surface and processing: PVC film, brushing, precision milling and tight-tolerance cutting are charged separately.
- Quantity and freight: weight drives freight, so confirm whether quotes are per kilogram, per sheet or per piece and which delivery term applies.
To compare offers fairly, convert every quote to a price per kilogram on the same delivery term, and check that the alloy, temper, standard and certificate are identical.
Cutting, machining and bending 1/4 inch plate
Sawing
Carbide-tipped circular or panel saws cut 1/4 in plate cleanly and fast. Use blades with a negative or low positive hook and a lubricant to stop aluminium loading the teeth.
Shearing
Heavy guillotine shears handle 1/4 in in softer alloys such as 3003 and 5052. Shear capacity is usually rated for mild steel, so check the shear's aluminium rating for 6061-T6 and 7075.
Waterjet
No heat-affected zone and tolerances of a few tenths of a millimetre; ideal for 7075 and for complex outlines.
Laser and plasma
Fibre lasers cut 6.35 mm aluminium well with nitrogen assist; plasma is faster but leaves a wider kerf and a heat-affected edge that may need dressing.
Bending
Bend 5052-H32 with an inside radius around 1 × thickness; 6061-T6 needs roughly 1.5 – 3 × thickness and is best bent across the rolling direction. Do not cold-bend 7075-T6.
Machining and welding
6061 and 7075 machine to a bright finish with sharp carbide tools. 5052, 5083 and 6061 weld by MIG or TIG; 7075 and 2024 are not normally fusion welded.
For more on cutting methods and their trade-offs, see our guide to CNC aluminium machining.
Common uses for 1/4 inch aluminium plate
- Transport: trailer and truck-body side and floor plates, step plates, toolbox lids, battery enclosures and mounting brackets
- Marine: 5083 and 5052 hull bottoms for small boats, transom and console plates, dock and gangway components
- Machinery: mounting plates, guards, adaptor plates, robot and conveyor brackets, usually in 6061-T651
- Building: base and connection plates, balustrade fixings, column covers and heavy architectural panels
- Aerospace and defence: 2024 and 7075 fittings, doublers and ground-support equipment
- Signage and display: engraved or anodised nameplates, heavy sign blanks and fixtures
Common mistakes when buying 1/4 inch plate
- Assuming 6 mm and 1/4 inch are interchangeable: they differ by 0.35 mm and about 6 % in weight.
- Ordering 6061-T6 for a part that needs heavy machining: specify T651 to keep the part flat.
- Ordering 6061-T6 for a tightly bent part: 5052-H32 or annealed material is far more forgiving.
- Forgetting that diamond plate thickness may be measured with or without the raised pattern.
- Comparing prices without checking that alloy, temper, standard and certificate match.
- Leaving out protective film on cosmetic faces, which leads to scratches in transit and fabrication.
References and standards
- ASTM B209 – Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate
- ANSI H35.2 – Dimensional Tolerances for Aluminum Mill Products (The Aluminum Association)
- EN 485-2 – Aluminium and aluminium alloys: sheet, strip and plate, mechanical properties
- The Aluminum Association – Aluminum Standards and Data
- ASM Handbook, Vol. 2 – Properties and Selection: Nonferrous Alloys
1/4 inch aluminium (aluminum) plate: questions buyers ask
How much does a 4 × 8 sheet of 1/4 inch aluminum plate weigh?
In 6061 it weighs about 112 lb (50.9 kg). The same sheet in 5052 is about 111 lb, and in 7075 about 117 lb, because of the small density differences between alloys.
Is 1/4 inch aluminium sheet or plate?
Under ASTM B209 it is plate: plate starts at 0.250 in. Anything thinner is sheet. Under European standards plate begins above 6 mm, so 6.35 mm is plate there too.
What is 1/4 inch in millimetres?
Exactly 6.35 mm. The nearest common metric plate thickness is 6 mm, which is 0.35 mm thinner.
Which is better for 1/4 inch plate, 5052 or 6061?
Choose 5052-H32 for bending, welding and marine exposure, and 6061-T651 for machined parts and higher strength. 6061-T6 is about one third stronger in yield but cracks if bent to tight radii.
Can you cut 1/4 inch aluminium plate to size?
Yes. Metline supplies full sheets or saw-cut, waterjet-cut and CNC-profiled blanks to your drawing, with protective film where needed.
Do you supply 1/4 inch plate outside India?
Yes. Metline ships plate worldwide from Mumbai on EXW, FOB, CIF or DAP terms, with an EN 10204 3.1 mill certificate and export packing.
Need 1/4 inch aluminium plate?
Tell us the alloy, temper, size, quantity and destination. We will confirm availability, certification and a delivered price.
