Complete Guide to Washers: Weight and Size Chart in KG for Precision Fastening
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- February 23rd, 2026
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A reliable washers weight and size chart in kg helps engineers, technicians, and hobbyists select the correct washer for a fastening task. This guide explains common washer types, how dimensions affect mass in kilograms, how to read and use size charts, and references to international standards to support accurate selection.
- Washers distribute load and prevent damage around fastener holes.
- Weight depends on material, outer/inner diameters, and thickness; charts often list mass per piece in kg or g.
- Common standards include ISO, DIN, and ASME; consult the relevant standard for critical applications.
Understanding washer types and functions
Washers are thin plates with a hole used to distribute load, prevent loosening, and protect surfaces. Common types include flat (plain) washers, spring (split) washers, toothed (lock) washers, and countersunk washers. Each type has specific geometry that affects size, bearing area, and mass.
Flat (plain) washers
Flat washers provide a bearing surface that spreads load over a larger area. They are the most frequently used type for general assembly and are defined by inner diameter (ID), outer diameter (OD), and thickness.
Lock and spring washers
Locking washers resist loosening under vibration. Their mass is typically slightly higher than a comparable flat washer due to additional material (e.g., split or serrations).
Washers weight and size chart in KG — quick reference
Charts display washer dimensions (ID, OD, thickness) and the corresponding weight per piece, often in grams or kilograms. Typical entries show nominal fastener size (metric M numbers or imperial fractions), ID matching the bolt shank, and standard OD and thickness values.
Example layout of a size-weight chart
A standard chart may include columns for:
- Nominal size (e.g., M6, M8)
- Inner diameter (mm)
- Outer diameter (mm)
- Thickness (mm)
- Weight per piece (kg)
Sample values (illustrative)
For reference (values approximate): an M6 flat washer ID 6.4 mm, OD 12 mm, thickness 1.6 mm might weigh ~0.0025 kg (2.5 g). An M12 flat washer with ID 12.5 mm, OD 24 mm, thickness 3.2 mm could weigh ~0.015 kg (15 g). Always consult manufacturer or standards for exact figures.
How material and dimensions affect weight
Density and volume determine mass. Common washer materials include carbon steel (~7.85 g/cm3), stainless steel (~8.0 g/cm3), brass (~8.4 g/cm3), and aluminum (~2.7 g/cm3). A thicker or larger OD washer has more volume and therefore greater mass. Corrosion coatings add negligible mass for single pieces but can matter in bulk calculations.
Calculating weight from dimensions
Basic method: compute washer volume as the volume of a cylindrical ring (π × thickness × (OD^2 - ID^2)/4) and multiply by material density. Convert cubic millimeters to cubic centimeters before applying density (1 cm3 = 1000 mm3) to obtain mass in grams, then to kilograms.
Measuring washers and verifying charts
Use calipers to measure ID, OD, and thickness to confirm chart entries. For critical assemblies, verify material grade and hardness. Measurement tolerances should align with the referenced standard (ISO, DIN, or ASME) to ensure compatibility with bolts and nuts.
Standards and authoritative references
International standards specify dimensions, tolerances, and recommended uses for many washer types. Relevant organizations include ISO, DIN, ASTM, and ASME. For official dimension tables and definitions, consult the International Organization for Standardization: ISO. Technical libraries and engineering handbooks also provide conversion tables and material densities.
Practical tips for choosing washers
Match washer ID to bolt shank to avoid load concentration. Choose OD and thickness to provide adequate bearing area and stiffness. Select material compatible with the fastener and environment to prevent galvanic corrosion. For weight-sensitive designs, use aluminum or thinner sections, balancing mechanical requirements.
Bulk and inventory considerations
When ordering by mass, convert piece weights from charts into kilograms for accurate procurement. For large quantities, small per-piece differences magnify total weight and cost.
Common errors when using charts
Frequent mistakes include assuming all washers of the same nominal size share identical OD and thickness across standards, ignoring material density when calculating weight, and failing to verify tolerances for precision assemblies.
FAQ
Where to find a washers weight and size chart in kg?
Official standards bodies, engineering handbooks, and manufacturer catalogs provide size-weight charts. Check ISO, DIN, ASME tables, or supplier technical datasheets for exact mass per piece expressed in grams or kilograms.
How is washer weight calculated from dimensions?
Compute the washer's ring volume from OD, ID, and thickness, convert to cubic centimeters, then multiply by material density to get mass in grams. Divide by 1000 to convert to kilograms.
Do coatings significantly change washer weight?
Typical electroplating or passivation layers are thin and add negligible mass for individual washers, but for large orders the added mass can be measurable in total shipping weight.
Which standards define washer dimensions?
ISO (e.g., ISO 7090 for certain flat washers), DIN (German Institute for Standardization), and ASME/ASTM standards include dimension and tolerance tables. Refer to the applicable standard for the required washer type and class.
Can the same chart be used for imperial and metric fasteners?
Charts are usually specific to metric (M sizes) or imperial (fractional inches). Use the appropriate table or a conversion chart and verify that tolerances and OD/ID values match the intended standard.
