Engineering Tools · Spring Washer Specs
Spring Washer Size Chart: M3–M24 Dimensions and Unit Weight
Family index of the spring washer size charts: the 10 sizes we quote (M3–M24) with their inner diameter d range, catalogue outer diameter D, section S(b) nominal, free height H and unit weight (carbon steel basis at 7.85 g/cm³) in one table. Each size opens its own page. The dimension columns come value by value from GB/T 93-2025 Table 1; the outer diameter and unit weight come from our catalogue weight coefficients, and the gap between the two bases is listed size by size on the per-size pages.
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Size Index ({sizes})
Click a size for its own page (standard-value table for that size, outer diameter and thickness coefficient, all 24 sizes of GB/T 93-2025 Table 1, size-by-size edition comparison, material density conversion, spreading limits and a quote). The inner diameter d and free height H are the ranges given in GB/T 93-2025 Table 1; Table 1 has no outer diameter column, so D is on our catalogue basis; the unit weight is a carbon steel estimate.
| Size | Inner d (Table 1 range, mm) | Outer D (catalogue, mm) | S(b) nominal (mm) | Free height H (Table 1 range, mm) | Unit weight (g/pc, carbon steel) |
|---|---|---|---|---|---|
| M3 | 3.1–3.4 | 5.1 | 0.8 | 1.6–2 | 0.08 g |
| M4 | 4.1–4.4 | 6.8 | 1.1 | 2.2–2.75 | 0.17 g |
| M5 | 5.1–5.4 | 8.8 | 1.3 | 2.6–3.25 | 0.39 g |
| M6 | 6.1–6.5 | 11.8 | 1.6 | 3.2–4 | 1.02 g |
| M8 | 8.1–8.5 | 14.8 | 2.1 | 4.2–5.25 | 1.91 g |
| M10 | 10.2–10.7 | 18.1 | 2.6 | 5.2–6.5 | 3.51 g |
| M12 | 12.2–12.7 | 21.1 | 3.1 | 6.2–7.75 | 5.57 g |
| M16 | 16.2–16.8 | 27.4 | 4.1 | 8.2–10.25 | 12.2 g |
| M20 | 20.2–21 | 33.6 | 5 | 10–12.5 | 22.5 g |
| M24 | 24.3–25.3 | 40 | 6 | 12–15 | 37.9 g |
Basis and Disclosed Assumptions
Where the numbers come from
- The dimension columns (inner diameter d, S(b) nominal, free height H) come value by value from GB/T 93-2025 Fasteners — Single coil spring lock washers — Normal type, Table 1 (PDF pages 8–9), carried in utils/springWasherCalc.ts with a check script comparing every cell (9 columns × 24 sizes, all equal).
- The outer diameter D and the unit weight come from the product catalogue weight coefficients (MySQL prd_sku.spec_json.weightCalc: method = washer_formula, version = v2, formula = ring_area*thickness); the unit weight is recomputed with the identical parameters and formula π/4·(D²−d²)·t·ρ, with the bore at the nominal diameter and ρ = 7.85 g/cm³ for carbon steel.
- GB/T 93-2025 Table 1 has no outer diameter column, so D is on our catalogue basis and is labelled as such; it is never presented as a Table 1 value. The gap between the two bases is listed size by size on each per-size page and is not back-calculated here.
Scope and limits
- This chart covers only the 10 sizes we quote (M3–M24). Table 1 has 24 sizes in all, and the ones we do not quote carry standard dimensions only and no weight — no coefficient, no figure.
- The dimensions are standard nominal values, not measurements of a specific batch; real parts also vary with tolerance and coating.
- The unit weight is a quotation estimate (quoting, freight, packing) computed from the nominal bore, so it runs above a Table 1 inner-diameter basis; the spread is given per size in the edition-difference table of each page. Theoretical estimate tolerance ±10%, and settlement follows actual weighing.
- This page publishes no spring force, clamping force or test load figures — GB/T 93-2025 gives none, and elasticity, torsion and hydrogen embrittlement resistance are referenced to GB/T 94.1.
References
- GB/T 93-2025 Fasteners — Single coil spring lock washers — Normal type (issued 2025-10-31, effective 2026-02-01, replacing GB/T 93—1987) — source of the dimension columns and the scope note on this page, transcribed value by value with page references (Table 1 = PDF pages 8–9, scope note = PDF page 7)
- GB/T 94.1-2008 Specification for spring washers — Single coil spring lock washers (National Standards Information Public Service Platform) — elasticity, torsion, hydrogen embrittlement resistance and test methods are referenced to it; GB/T 93-2025 gives no test method detail
- GB/T 859-2025 Fasteners — Single coil spring lock washers — Light type (National Standards Information Public Service Platform) — the companion light series; its table splits S and b, so its values are not used here and it serves only as a system cross-reference
- Product catalogue weight coefficients (MySQL prd_sku.spec_json.weightCalc, method = washer_formula, version = v2) — source of the outer diameter, thickness coefficient and unit weight, identical to the product pages and the weight calculator
Off-table combinations or a batch total to work out?
The weight calculator covers spring washers: pick the size and the material and get the unit weight, the batch weight and pieces per tonne — on the same engine and data source as this table.
Open the weight calculatorCite this chart
YAXIIO. Spring Washer Size Chart: M3–M24 Dimensions and Unit Weight. https://www.yaxiio.com/en/tools/spring-washer-chart (accessed 2026-10-29).
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Frequently asked questions
Our unit weight differs from what I get from the Table 1 dimensions — why?
Two different bases. Our weight uses the catalogue coefficients (outer diameter D × thickness coefficient t) in π/4·(D²−d²)·t·ρ with the bore at the nominal diameter, while Table 1 gives the inner diameter as a range, 12.2–12.7 mm at M12. A smaller bore means a larger ring area, so our unit weight sits above a Table 1 inner-diameter basis, and each page's edition-difference table gives the spread size by size. It is a basis difference, not an error: quotations follow our basis, dimensional verification against the standard follows Table 1.
Can a spring washer be used in a 10.9 / 12.9 property class joint?
GB/T 93-2025 says in its scope note: where used with bolts and screws of property classes 10.9 and 12.9, attention should be paid to the washer spreading phenomenon — attention, not prohibition. A high-strength joint carries high preload and the washer may open up radially, changing the fit and the clamping state, so in practice you check torque against the target preload (our torque chart for the same size gives ranges by the K-factor method) and, where needed, switch to or add another locking method, decided by the designer from the joint load and vibration duty. We publish no spring or clamping force figures.
Should a spring washer be used together with a flat washer?
A common arrangement adds a flat washer between the part and the spring washer: it gives the spring washer a flat bearing face, spreads the load and reduces damage to the joint surface. The cost is one more interface that could move and a little extra stack height, so the choice belongs to the designer. Our washer weight chart gives flat and spring washers side by side for the same size (the spring washer row there follows the calculator's internal dimension basis; the gap versus the catalogue coefficients is listed in each page's edition-difference table).
Next: work out your order, or pick the size by standard
Related References
Weight calculator (spring washer)
Off-table combinations, batch totals and material conversion; same engine and data source as the charts.
Flat / spring washer weight chart
Flat and spring washer rows for the same size: dimensions, unit weight and bulk weight; the spring washer row follows the calculator's internal basis.
Bolt torque chart
Preload first when you assess spreading risk: torque ranges and target preload for the same size by property class and friction state.
Spring washer product catalog
GB/T 93 series single coil spring lock washers — request a quote by size, material and coating.
Disclaimer: this chart combines standard table values with quotation estimates as engineering reference material for selection, quoting and fit checks; it is not a design basis or an acceptance standard, and dimensional acceptance follows the standard edition named in your drawing or contract.