Split Shot Size and Weight Chart + Fly Fishing Calculator
Split shot sizes run backwards: a size 8 weighs about 0.06 grams, a size 4 about 0.20 g, a BB about 0.60 g and a 3/0 about 1.9 g. For a nymph rig, start at about 0.05 grams per foot of depth in slow current and roughly 0.12 grams per foot in fast water: three feet of slow water needs one size 5 (0.15 g), six feet of fast water about 0.7 g, a BB plus a size 7. Place shot 10 to 12 inches above the top fly and set the indicator at 1.5 to 2 times the depth.
Nymph fishing is a depth game, and split shot is the fastest way to change depth without changing anything else. The number people get wrong is not the shot size, it is how much total weight the current actually demands. Drag on a sinking fly rises roughly with the square of water speed, so doubling the current speed does far more than double the weight you need.
How much weight does this run need?
A field starting point, not a physical model. Real depth depends on line angle, drift length, leader diameter and how much line is on the water. Add weight until you tick bottom occasionally, then stop.
How much weight does a nymph rig actually need?
The working rule is about 0.05 grams per foot of depth in slow water, scaled up by the current. Slow glides need roughly that. A moderate walking-pace riffle needs about 1.6 times as much. Genuinely fast pocket water needs about 2.4 times as much, because the fly has less time in the water column before the drift is over.
The reason the multiplier grows is that hydrodynamic drag on the fly, tippet and shot scales with the square of velocity. A current twice as fast exerts roughly four times the lifting force on the leader, so the weight has to grow faster than the speed does. This is the same physics that makes wading dangerous at knee depth in fast water, and it is worth internalising for both reasons.
| Depth | Slow water | Moderate | Fast | Typical fast-water combination |
|---|---|---|---|---|
| 2 ft | 0.10 g | 0.16 g | 0.24 g | One size 4 |
| 3 ft | 0.15 g | 0.24 g | 0.36 g | One size 2 |
| 4 ft | 0.20 g | 0.32 g | 0.48 g | One size 1 plus a size 8 |
| 5 ft | 0.25 g | 0.40 g | 0.60 g | One BB |
| 6 ft | 0.30 g | 0.48 g | 0.72 g | One BB plus a size 7 |
| 8 ft | 0.40 g | 0.64 g | 0.96 g | Two BB |
| 10 ft | 0.50 g | 0.80 g | 1.20 g | Two BB plus a size 4 |
Those figures are the total the rig needs, so a weighted fly counts toward it. A tungsten bead head contributes roughly 0.12 grams, which in two feet of slow water is already the entire requirement. That is why a well-chosen point fly often means no shot at all.
What do the split shot sizes weigh?
The size scale runs backwards, like tippet: a bigger number is a smaller shot. Removable shot with the two small ears is worth the small extra cost because you can take it off without cutting the leader, which is the whole point of adjustable weight.
| Shot size | Grams | Grains | Ounces | Typical use |
|---|---|---|---|---|
| Size 8 | 0.06 | 0.9 | 0.002 | Fine tuning, spring creeks, shallow flats |
| Size 7 | 0.11 | 1.7 | 0.004 | Fine tuning, spring creeks, shallow flats |
| Size 5 | 0.15 | 2.3 | 0.005 | The everyday trout sizes, 2 to 4 ft of water |
| Size 4 | 0.20 | 3.1 | 0.007 | The everyday trout sizes, 2 to 4 ft of water |
| Size 3 | 0.27 | 4.2 | 0.010 | The everyday trout sizes, 2 to 4 ft of water |
| Size 2 | 0.35 | 5.4 | 0.012 | Deeper runs and moderate current |
| Size 1 | 0.44 | 6.8 | 0.016 | Deeper runs and moderate current |
| Size BB | 0.60 | 9.3 | 0.021 | Deeper runs and moderate current |
| Size 3/0 | 1.90 | 29.3 | 0.067 | Heavy water, deep runs, big rivers |
A single assortment box with four sizes covers everything above and lasts several seasons. It is one of the cheapest items in the kit and one of the most frequently forgotten.
Where does the shot go on the leader?
Ten to twelve inches above the top fly, and always pinched above a knot rather than on bare tippet. Shot on bare tippet slides down under the load of a drift, jams against the fly, and either kills the presentation or crushes the tippet at the point where it slid.
On a two fly rig, the natural place is immediately above the knot where the dropper tag comes off. That gives you a positive stop, keeps the shot out of the fly's action, and means a snag usually costs you the shot rather than the whole rig, which is exactly the failure mode you want.
How far above the fly should the indicator sit?
One and a half to two times the water depth. In three feet of slow water that is about four and a half feet from indicator to the top fly. In fast water go to the full two times, so six feet.
The extra distance is not slack. Current pushes the flies downstream of the indicator, so the leader hangs at an angle rather than straight down, and the straight-line distance from indicator to fly has to be longer than the vertical depth to compensate. The faster the water, the shallower that angle and the more length you need.
Yarn indicators are more sensitive than plastic bobbers and land far more softly, which matters on pressured water. A pinch of strike indicator wool treated with floatant sits in the surface film and shows a take that a hard indicator would swallow. The full rigging sequence is in how to rig a nymph setup.
Is lead split shot allowed where I fish?
Not always. Several states and many national park waters restrict or prohibit lead sinkers and lead split shot because waterfowl ingest them from the riverbed, and some catch and release fisheries require non-toxic weight outright. Tin, bismuth and tungsten shot are all sold as drop-in replacements, and tungsten is actually denser than lead so it is physically smaller for the same mass.
Regulations change, and they vary by water rather than by state, so check the current rules for the specific river before you buy. That is the same discipline required for felt wading boot soles, which are banned in several states for invasive species reasons and are covered in the wading safety guide.
Where to go next
If you are fishing a sinking line rather than shot, the sink rate calculator is the right tool. Size the tippet the shot is riding on with the leader and tippet calculator, and check the tippet size chart for the diameters. The nymph rigging guide covers where to put the drift once the depth is right.
Frequently asked questions
How much split shot do I need to get a nymph down?
As a starting point, about 0.05 grams for every foot of water depth in slow current, and roughly two and a half times that in fast water. Three feet of slow water needs one size 5 shot at about 0.15 grams. Six feet of fast water needs closer to 0.7 grams, which is a BB plus a size 7. Add shot until you tick bottom occasionally, then stop.
Where should split shot go on the leader?
Ten to twelve inches above the top fly, or immediately above the tag knot on a two fly rig. Too close and the shot spooks fish and kills the fly action; too far and the fly rides well above the shot and never reaches the fish. Pinch it above a knot rather than on bare tippet so it cannot slide down and jam against the fly.
How far above the fly should the indicator be?
One and a half to two times the water depth. In three feet of slow water set the indicator about four and a half feet above the fly; in fast water go to two times depth, so six feet. The extra length is not about depth alone, it accounts for the angle the leader hangs at when current pushes the fly downstream of the indicator.
Is split shot better than a weighted fly?
They solve different problems. A tungsten bead sinks the fly itself and keeps a clean profile, which matters in clear water and to fish that inspect. Split shot lets you adjust weight in seconds without changing flies, which matters when you are moving between runs of different depth. Most anglers use a weighted point fly plus one adjustable shot and change the shot rather than the fly.
Is lead split shot legal where I fish?
Not everywhere. Several states and many national parks restrict or ban lead sinkers and lead split shot because of the risk to waterfowl that ingest them, and some fisheries require non-toxic weight outright. Tin, tungsten and bismuth shot are all available and tungsten in particular is denser than lead, so it is smaller for the same weight. Check the current regulations for your water.
Why does my rig keep tangling with split shot on it?
Because shot changes the timing of the cast. A weighted rig cannot be false cast like a dry fly: it needs an open loop, a slower stroke and a distinct pause. Use a water-loaded lob or a single back cast rather than three false casts, keep the rod tip travelling in a wider arc, and stop the rod higher on the forward stroke so the flies land downstream of the line.
How we choose: we compare published manufacturer specifications, line and leader standards, and verified owner reviews across retailers. We do not test gear in person, and every diameter, grain weight and breaking strength quoted here is the manufacturer's published figure unless we say otherwise, so check the spool label before you trust a number. Nothing here is professional instruction. Wading moving water is the real hazard in this sport: wear a snug wading belt, know the water temperature, and turn back rather than push through a crossing you are unsure of.
