Breaks at
—
lb
Line on the spool is not the line at your hook. Enter your line and the knot you actually tie to see the real breaking strength, how much you lose to the knot, and the drag setting that number supports.
| Knot | Retained | Breaks at (lb) | (kg) |
|---|
The number on the spool describes a straight piece of line in perfect condition. What you actually fish is a line with a knot in it, and a knot is a controlled bend. Bend any material into a tight radius and the outer fibres stretch further than the inner ones, so the load concentrates on the outside of the curve.
That is why line almost never breaks in the middle. It breaks at the knot — and the shorter the knot's radius and the fewer turns carrying the load, the more strength it costs you. This calculator applies the retention figures from published knot testing so you can see the difference before you pick a knot rather than after it fails.
The same knot behaves differently on each material. Retention percentages are the middle of the range reported in published knot testing — your brand of line will vary by a few points.
| Knot | Braid | Monofilament | Fluorocarbon | Use it for |
|---|---|---|---|---|
| Palomar | 95% | 95% | 93% | Hooks, swivels, drop shot. Best all-round knot for braid. |
| FG knot | 95% | 88% | 92% | Joining braid to a fluorocarbon leader. Thinnest and strongest join. |
| Uni knot | 88% | 90% | 87% | All-round terminal knot; doubled up as a double uni for leaders. |
| Trilene knot | 78% | 85% | 82% | Monofilament and fluorocarbon terminal knot. |
| Improved clinch | 75% | 87% | 83% | Fine on mono. Avoid on braid — it slips. |
| Surgeon’s knot | 82% | 80% | 78% | Joining lines of very different diameter, fast. |
| Blood knot | 70% | 80% | 75% | Classic join for similar diameters. Weakest common option. |
The pattern is worth remembering: braid punishes any knot that relies on friction, and rewards knots that double the line through the eye. Monofilament is the most forgiving material on the list.
| Mistake | Typical cost | Fix |
|---|---|---|
| Dry-seating the knot | 10–20% of rating | Wet it before you pull it tight. Friction burns the line and the damage is invisible. |
| A scuffed last few feet | Up to 50% | Run the last 6 ft through your fingers after every fish and every snag. If it feels rough, cut it off and retie. |
| A tag end that is too short | Sudden failure | Quarter inch on braid. Knots do not snap, they creep — and a short tag gives them nowhere to creep to. |
A 20 lb braid that breaks at 15 lb because of a knot and a scuff is a 15 lb setup, not a 20 lb one. Set your drag from what actually holds — the Drag & Leader Calculator does that across your whole line system, and the line strength chart shows what each line class is really good for.
A good knot on cheap line beats a bad knot on expensive line — but matching the knot to the material is what actually keeps it holding.
Braid rewards the Palomar and punishes the clinch. Buy a line you will retie often and a spool long enough to cut off the damaged end.
Check current price on Amazon →Leader is a separate material with its own knot rules. Keep a spool of the class that matches your braid diameter.
Check current price on Amazon →Trimmed tags and consistently seated knots. Clippers matter more than they sound — scissors crush braid.
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Full detail for every calculator is on the methodology page.
Every knot takes a cut of your line, and the size of that cut is predictable. The knot strength chart ranks every common knot, the best knots for braid guide covers the ones that do not slip, and the drag and leader calculator turns the number into a usable drag setting.
Yes, and by more than most anglers expect. A knot bends the line into a tight radius, which concentrates stress at that point, so the line always breaks at the knot rather than in the middle. Well-tied knots keep 90 to 100% of the line rating; a mediocre knot on the wrong line type can drop it to 75%.
The Palomar for terminal tackle and the FG knot for joining braid to a leader. Both typically retain 95% or more. The knot to avoid on braid is the improved clinch — slick PE line creeps under load and that knot can lose a quarter of the line rating.
From the knot, because that is where the line actually breaks. If a 20 lb braid with a Palomar holds about 19 lb, setting drag at one third of the line rating (6.6 lb) leaves you a comfortable margin. Setting it at one third of a weak knot value would be far too cautious and you would lose fish to a slipping drag.
On monofilament and fluorocarbon, 1/8 inch is enough. On braid, leave more — a quarter inch or so. Slick braid creeps, and a short tag end is the most common reason a braid knot slips after twenty casts.
Because they slip rather than snap. A knot that is not fully seated works loose under repeated load cycles, and the line also heats up as it friction-burns during seating. Lubricate knots with water or saliva before you pull them tight, and seat them firmly the first time.
Drag & Leader Calculator · Fishing line strength chart · Line Diameter Converter · How to tie a Palomar knot · 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 · Line Diameter Converter · Reel Line Capacity Calculator · Shock Leader Calculator · Fly Leader Length Calculator
Knots and hooks: 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 Hook Size Chart · Fishing Line Strength Chart · Fishing Knot Strength Chart · Fishing Swivel Size Chart · Leader Size Chart
Please note: every figure on this page is an estimate, not a measured result. Tolerances between brands, wear on your gear and your own setup all change the outcome. TackleCalc has no connection to any brand mentioned here, and this content is for reference only.