Knot guide · Beginner
Grinner Knot (Uni Knot): How to Tie It
The grinner knot, known internationally as the uni knot, is the Swiss Army knife of fishing knots. It ties hooks, swivels and leads to almost any line, ties easily in the dark, handles heavy mono well, and doubled up as the double grinner it becomes one of the most reliable line to line joins in fishing.
Published by the GilledIt editorial team · Last reviewed 2026-07-07 · Part of the fishing knot library
Step by step
How to tie the grinner knot (uni knot)
- 1
Thread and double back
Thread the line through the eye and double it back so the tag end runs alongside the standing line.
- 2
Form the loop
Form a loop by laying the tag end back over the doubled section of line.
- 3
Wrap through the loop
Wrap the tag end through the loop and around the doubled line 4 to 6 times.
- 4
Snug and slide
Wet the knot and pull the tag end to snug the wraps together, then slide the finished knot down to the eye.
- 5
Trim
Trim the tag end and test the knot with a firm, steady pull.
Two rules apply to every knot: wet it with saliva before pulling it tight, because dry friction weakens mono and fluorocarbon at the exact point you need strength, and tighten slowly, then test with a firm pull before you cast.
How strong is it?
Retains around 90 to 95% of line strength. Exact figures vary with line type, diameter and how well the knot is tied, so treat any percentage as a guide, not a guarantee.
When to use the grinner knot (uni knot)
Hooks, swivels and leads on any line type, especially when you need a dependable knot tied by feel in the dark or in heavy mono. Tie two grinners facing each other on overlapping lines and you have the double grinner, a sensible alternative to the FG knot for joining braid to a leader.
Grinner Knot (Uni Knot): common questions
Yes. Grinner is the traditional UK name and uni is the international one, but the knot is identical. Sea anglers in particular rate it because it ties easily in the dark and handles heavy monofilament well.
Two grinner knots tied facing each other on overlapping lines, then drawn together. It is one of the most reliable line to line joins in fishing and the best easier alternative to the FG knot for connecting braid to a fluorocarbon or mono leader while you learn the FG.
Four to six wraps through the loop is the standard range. Lean towards more turns on thin or slippery lines like light mono and braid, and fewer on thick, heavy mono where too many wraps stop the knot seating cleanly.
Both are excellent hook knots with similar strength. The palomar edges it for outright strength and simplicity, but it needs the whole hook or lure passed through a loop. The grinner avoids that, so it wins for big lures, trebles and hook patterns where the palomar is impractical.
Keep learning
Related knots
Palomar Knot
Any time you tie a hook, swivel or snap link to mono, fluorocarbon or braid. Its only real weakness is practical rather than structural: the whole hook or lure has to pass through the loop, which gets awkward with big lures and treble hooks.
Read the guideFG Knot
Joining braided mainline to a fluorocarbon or mono leader, especially in lure fishing where the join must pass through the rod rings on every cast. Practise it at home five or six times before you trust it on the bank; the double grinner is the fallback while you learn.
Read the guideSurgeon's Knot
Joining two lines of similar diameter quickly, attaching tippet to a fly leader, or building a paternoster link, especially mid session when speed matters. It is bulkier than a blood knot and sits slightly off axis, so it is not the join for repeated casting through small rings.
Read the guideFor all ten knots in one long read, see the fishing knots guide, or browse the full knot library. Ready to put it to work? The carp rig library shows what to tie next.
Practise at home, log the results on the bank
Find UK venues with species, prices and facilities, then log every catch your knots land in the GilledIt app.