Inches
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in
Pound test to diameter in inches and millimeters — for monofilament, fluorocarbon and braid — with PE number equivalents and the equivalent strength in the other two line types.
| Pound test | Inches | mm | Same diameter as |
|---|
Line diameter is the number that actually controls your fishing — not the number printed on the spool. Diameter sets how much line fits, how deep a lure runs, how fast current pushes your bait, and how much the line costs you in casting distance.
The conversion itself is simple: 1 inch = 25.4 mm. The useful part is the comparison. A 20 lb braid at 0.009 in is the same physical thickness as 6–8 lb monofilament, so it fits roughly 4× the line on the same spool — and casts like a much lighter line. Meanwhile the same-diameter fluoro is thinner than mono at the same strength because fluorocarbon is denser.
PE numbers come from the Japanese sizing convention, which is purely diameter-based: PE 1.0 is nominally 0.165 mm, PE 2.0 is 0.235 mm, PE 3.0 is 0.285 mm. Because the number describes thickness, not strength, the same PE rating can break anywhere from 15 to 30 lb depending on how many strands the braid has. Use PE when you are matching a Japanese reel, a line-capacity spec or a Japanese lure rating; use pound test when you are matching drag.
| PE number | Diameter (mm) | Diameter (in) | Roughly equals |
|---|---|---|---|
| PE 0.6 | 0.128 | 0.005 | 8 lb braid — ultralight |
| PE 0.8 | 0.148 | 0.006 | 10 lb braid — finesse spinning |
| PE 1.0 | 0.165 | 0.006 | 12–15 lb braid — all-round spinning |
| PE 1.2 | 0.185 | 0.007 | 15–17 lb braid |
| PE 1.5 | 0.205 | 0.008 | 18–20 lb braid — bass, inshore |
| PE 2.0 | 0.235 | 0.009 | 20–25 lb braid |
| PE 2.5 | 0.260 | 0.010 | 25–30 lb braid |
| PE 3.0 | 0.285 | 0.011 | 30–40 lb braid — baitcaster heavy |
| PE 4.0 | 0.330 | 0.013 | 40–50 lb braid |
| PE 5.0 | 0.370 | 0.015 | 50–65 lb braid — muskie, saltwater |
| PE 6.0 | 0.405 | 0.016 | 65–80 lb braid — offshore |
PE diameters are the nominal JAFTMA values; individual braids vary by a few thousandths of a millimeter depending on strand count and coating.
Full detail for every calculator is on the methodology page.
Line diameter drives capacity, casting distance and sink rate at once. The line diameter chart puts every material side by side, the reel line capacity calculator shows how much of it fits your spool, and the braid versus mono versus fluorocarbon guide explains the trade-offs.
About 0.009 in / 0.23 mm in most brands — the thickness of 6–8 lb monofilament, or roughly PE 1.5–2. That is why braid lets you fish heavy line on a light spinning reel.
No. PE describes diameter only. The same PE 1.5 can be sold as 18 lb by one brand and 25 lb by another, because strand count and weave change the breaking strength.
Fluorocarbon is denser, so less material is needed for the same strength. It also sinks — the reason it is the standard leader for bottom contact baits.
Diameter for spool fill, backing amount and lure depth; pound test for drag and abrasion. Getting these two goals confused is the most common tackle mistake there is.
You have the millimeters and the PE size. These are the spools that match.
Approximately 0.009 in / 0.229 mm, PE 1.5–2. The diameter most anglers should start with.
Check current price on Amazon →About 0.006 in / 0.15 mm, PE 0.8. Finesse diameter for spinning reels and light presentations.
Check current price on Amazon →Diameter matters here too — leader that is too thick kills lure action on finesse rigs.
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Braid ↔ Mono Diameter Converter · Reel Line Capacity Calculator · Sinker Weight Converter · Lure Weight Calculator · Braid vs mono vs fluorocarbon
Weight and depth: Lure Weight Calculator · Jig Head Weight Calculator · Sinker Weight Converter · Lure Sink Rate Calculator · Trolling Depth Calculator · Downrigger Depth Calculator
Line and leader: Braid to Mono Converter · Reel Line Capacity Calculator · Shock Leader Calculator · Fly Leader Length Calculator
Knots and hooks: Knot Strength Calculator · Hook Size Selector
Reel, drag and cast: Reel Gear Ratio Calculator · Casting Distance Calculator · Drag and Leader Calculator
Fish and catch: Fish Weight Calculator · Fillet Yield Calculator · Fly Line Weight Calculator
Reference charts: Fishing Line Diameter Chart · Fishing Swivel Size Chart
Also worth reading: Baitcaster line capacity
Estimates only: the values shown are a starting point, not a guarantee. Products of the same stated size differ between makers, so your own result will vary. TackleCalc is not affiliated with any manufacturer, and these figures are a guide rather than a guarantee.