Sports netting twine gauge chart: every published number, with its source
Twine gauge (#12, #21, #36, #42...) describes the thickness of the twine a net is woven from: published diameters run from 1.3 mm (0.051 in) at #15 to 4.0 mm (0.158 in) at #96, with breaking strengths from about 100 lb to over 1,100 lb. There is no single official chart: the figures below are the values actually published by five netting suppliers, shown side by side, with every disagreement left visible. No number on this page is averaged, rounded or estimated by us.
What does twine gauge (#21, #36, #42) actually mean?
The # number is a trade size, not an engineering standard. Practice Sports (Playbook) defines it as the gauge or overall thickness of the netting weave. In nylon multifilament, the gauge maps to a denier construction: the Nets & More chart lists #21 as 210/60 denier and #36 as 210/96, which is where the thickness and strength actually come from. Two practical consequences: a higher number means thicker and stronger twine, and two suppliers can label slightly different constructions with the same gauge.
Twine gauge chart: published diameters and breaking strengths
Sources: NM = Nets & More multifilament nylon chart (twine and knot test columns) · G = Gourock knotted nylon product pages (single twine breaking strength, stated as a minimum) · CNW = CNW Netting custom net specifications (method not stated) · D = Delta Net and Twine product pages (by construction) · PS = Practice Sports Playbook. All figures are for nylon unless noted.
| Gauge | Published diameter | Published breaking strength (lb) |
|---|---|---|
| #12 | 0.062 in / ~1.6 mm (G) | 100 lb min, single twine (G) · 103 lb, unspecified (CNW) |
| #15 | 0.051 in / 1.3 mm (NM) | 123 lb, unspecified (CNW) · 120 lb twine / 75 lb knot (NM) |
| #18 | 0.069 in / 1.8 mm (G) · 0.058 in / 1.47 mm (NM) | 191 lb min, single twine (G) · 165 lb, unspecified (CNW) · 150 lb twine / 100 lb knot (NM) |
| #21 | 0.079 in / 2.0 mm (G, PS) · 0.065 in / 1.65 mm (NM) | 210 lb min, single twine (G) · 208 lb, unspecified (CNW) · 204 lb, twisted (D) · ~190 lb, braided (D) · 190 lb twine / 125 lb knot (NM) |
| #24 | not published by any source we reviewed | 250 lb, unspecified (CNW) |
| #30 | 0.078 in / 1.98 mm (NM) | 310 lb twine / 280 lb knot (NM) |
| #36 | 0.0985 in / 2.5 mm (G, PS) · 0.085 in / 2.16 mm (NM) | 350 lb min, single twine (G) · 350 lb twine / 280 lb knot (NM) · 323 lb, unspecified (CNW) · 300 lb, braided (D) · 348 lb, tarred twisted (D) |
| #42 | 0.093 in / 2.4 mm (NM) | 375 lb, unspecified (CNW) · 375 lb twine / 300 lb knot (NM) |
| #60 | 0.116 in / 3.0 mm (NM) | 560 lb twine / 425 lb knot (NM) · approx. 400 lb, braided (D) |
| #72 | 0.138 in / 3.5 mm (G) · 0.125 in / 3.2 mm (NM) | 665 lb min, single twine (G) · 662 lb, unspecified (CNW) · 900 lb twine / 725 lb knot (NM) |
| #96 | 0.158 in / 4.0 mm (NM) | 898 lb, unspecified (CNW) · 900 lb twine / 725 lb knot (NM, identical to their #72 row) |
| #120 | not published by any source we reviewed | 1,140 lb, unspecified (CNW) |
Why do published breaking strengths differ for the same gauge?
The disagreements are not noise: the published data itself shows three causes.
- Twine test vs knot test. Nets & More publishes both columns: #36 breaks at 350 lb as straight twine but 280 lb at the knot. Memphis Net & Twine states the rule plainly: netting strengths are lower than twine strengths. A woven, knotted net is always weaker than the twine it is made from, which is why CNW's unqualified figures sit close to knot values while Gourock's single twine minimums sit higher.
- Construction. Same gauge, different product: Delta lists #36 braided nylon at 300 lb and #36 tarred twisted at 348 lb.
- Unqualified figures. Most published numbers state neither what was tested (twine or mesh), nor the condition (new, wet, UV-aged; Memphis's chart shows wet nylon testing below dry), nor any test standard. Across all five suppliers we reviewed, none cites ASTM, ISO or any named method. Gourock is the only one that qualifies its figures at all (single twine breaking strength, minimum).
The practical reading: treat a bare breaking strength figure as an upper bound measured on new, dry, straight twine, and assume the net itself holds meaningfully less at the knots. If a figure matters for your project, specify the condition in writing - that is exactly what a written quote is for.
Which twine gauge for which level of play?
The published recommendations converge on this pattern (batting and practice cages):
| Level | Published recommendation | Who publishes it |
|---|---|---|
| Youth / backyard | #21 poly (Little League) · #24 | Practice Sports · Batting Cages Inc |
| High school | #36 nylon minimum (stated as used by approximately 80% of high schools) · #36-#42 | Practice Sports · Batting Cages Inc |
| College | #42 minimum | Practice Sports, Batting Cages Inc |
| Commercial / professional | #60 minimum | Practice Sports |
| Outdoor installations | HDPE in #24 / #36 / #42; nylon preferred indoors | Batting Cages Inc |
These are seller recommendations, not league rules: no governing body we know of mandates a twine gauge. They are consistent with the strength data above, which is why we treat them as a reasonable starting point when we confirm a spec.
How does gauge translate to millimetres?
Most of the world, including our manufacturing partner, specifies twine in millimetres. The only complete gauge-to-mm table among our sources is the Nets & More denier chart; sports sellers publish just two anchors: #21 = 2.0 mm and #36 = 2.5 mm (Gourock and Practice Sports agree on both). Note the visible discrepancy: the denier chart puts the same gauges at 1.65 mm and 2.16 mm. No source explains the gap, so we show both rather than pick one.
Our own catalogue sidesteps the ambiguity: every spec is documented directly in millimetres (1 to 6 mm twine across 10 mm to 100 mm mesh, verified against factory samples, in polyester). Browse the netting families or use the Spec Finder to see which documented mm combinations fit your application.
How we compiled this chart
We collected every twine size and strength table we could find on public pages of five US netting suppliers (July 2026), kept each value exactly as published, attributed it, and refused to average across sources. Where sources disagree, both values are shown. Where nobody publishes a value, the row says so. One frequently-quoted page (RBI Gear) could not be re-verified directly at the time of writing and is deliberately not cited. Non-competing sources: theNets & More size and test chart,Delta Net and Twine product pages,Memphis Net & Twine andLee Fisher. Sports-netting sellers (Gourock, CNW Netting, Practice Sports, Batting Cages Inc) are credited by name next to each figure.
Frequently asked questions
What does the # number on sports netting twine mean?
The # number (gauge) describes the overall thickness of the twine the net is woven from. Practice Sports defines it as the gauge or overall thickness of the netting weave. Higher numbers mean thicker, heavier and stronger twine: published diameters run from about 1.3 mm at #15 to 4.0 mm at #96.
How strong is #21 twine?
It depends on who is measuring and what they measure. Published figures for nylon #21 range from 190 lb to 210 lb for the twine itself, and 125 lb at the knot (Nets & More). Gourock is the only seller that qualifies its figure: 210 lb minimum, single twine. No source we reviewed states a test standard.
Is #36 twice as strong as #21?
Not by the published numbers. Comparing like with like: 350 lb vs 210 lb single twine (Gourock), or 350 lb vs 190 lb twine test (Nets & More). That is roughly 1.7 to 1.8 times, not double. The knot-test gap is similar: 280 lb vs 125 lb.
What twine sizes does Sport Net Supply quote?
Our manufacturing partner documents twine in millimetres: 1, 2, 3, 4, 5 and 6 mm across mesh sizes from 10 mm to 100 mm, verified against factory samples. Using the diameters published by Gourock and Practice Sports, 2.0 mm corresponds to #21 and 2.5 mm to #36. We confirm the exact mm specification in writing on every quote.
Why do different websites list different breaking strengths for the same gauge?
Three reasons are visible in the published data: twine test vs knot test (the mesh is always weaker: 350 lb vs 280 lb for #36 at Nets & More), construction (braided 300 lb vs tarred twisted 348 lb for #36 at Delta), and unqualified figures with no stated method. None of the sources we reviewed cites a test standard.
Need the spec confirmed, not guessed?
Tell us the sport, the dimensions and the environment. We reply within 48 hours with the documented mesh and twine combination in writing - no invented figures, on this page or on your quote.
We reply within 48 hours with questions or a documented quote.