Trailer Hitch Ball Size Chart
Four standard ball sizes, what each is used for, and the three things that all have to match before you tow.
Reviewed for 2026 against the sources listed at the foot of this page. These are published specifications, not annual figures — the year records when the chart was last checked, not a change in the numbers.
| Ball diameter | Shank diameters made | Typical capacity range | Typical use |
|---|---|---|---|
| 1-7/8" | 3/4", 1" | 2,000 – 3,500 lb | Small utility trailers, teardrop campers, small boat trailers |
| 2" | 3/4", 1", 1-1/4" | 3,500 – 12,000 lb | The most common size. Most rental trailers, mid-size boats, small travel trailers |
| 2-5/16" | 1", 1-1/4", 2" | 6,000 – 30,000 lb | Large travel trailers, equipment and car haulers |
| 3" | 2" | 30,000 lb and up | Gooseneck and heavy commercial |
Ranges are CURT's published line, because that is a catalogue whose every figure can be checked. Other manufacturers differ, which is why these are typical rather than specifications. The figure stamped on your specific ball governs.
Do not read the shank column as a capacity ladder. A thicker shank does not mean a stronger ball. CURT lists a 2" ball on a 1" shank rated 12,000 lb and a 2" ball on a thicker 1-1/4" shank rated 10,000 lb — same diameter, thicker stem, lower rating. The shank has to fit your ball mount hole. It does not tell you what the ball will carry.
- Matched. The socket closes around the upper half of the ball. Shown at true relative size — the three diameters are close, which is exactly why they get confused.
- Undersized. A gap remains above the ball. The coupler appears to latch, then lifts free under load.
The ball and coupler must match exactly. A 2" ball in a 2-5/16" coupler will appear to latch and then release under load, because the socket never closes on anything. Read the size stamped on your coupler and use that.
Three things that must all be right
- Ball diameter matches the coupler. Stamped on the coupler. No exceptions, no "close enough".
- Shank diameter fits the ball mount hole. A shank rattling in an oversized hole concentrates load badly and works itself loose.
- Stamped capacity covers your loaded trailer weight. Not your empty weight, and not your usual load — the heaviest it will ever be.
Torque the nut, and torque it dry
One nut holds the ball in the mount. CURT publishes these figures for its own balls:
| Shank diameter | Torque |
|---|---|
| 3/4" | 160 ft-lb |
| 1" | 250 ft-lb |
| 1-1/4" | 450 ft-lb |
| 2" | 4,550 ft-lb |
Two things follow from that table. The figures are dry. Leave anti-seize and thread lubricant off the shank unless the ball maker calls for them, because a lubricated thread reaches a much higher clamp load at the same wrench reading — the number stops meaning what it was set to mean. And 4,550 ft-lb is not a driveway number. Consumer torque wrenches stop a long way short of it, so a 3" gooseneck ball is shop work rather than a tailgate job.
Other manufacturers publish slightly different figures for the same shank sizes. If your ball came with instructions, those govern.
How to check what you have
The coupler tells you the size. Look on the top or the side of the coupler casting; virtually all of them are marked. If the stamp is painted over or worn away, measure the inside diameter of the coupler socket rather than measuring an old ball, which may itself have been wrong.
The ball tells you the rating. Stamped on the crown. If there is no stamp, replace it — an unmarked ball has no traceable rating, and hitch balls are inexpensive relative to what they hold together.
Verify before you tow. These figures are a planning aid, not professional or engineering advice. Your real limits are the ones printed on your vehicle's door-jamb placard, your trailer's VIN plate, and your owner's manual - and those override anything calculated here. When numbers are close, weigh the rig and go with the more conservative answer.
Ball size covers the coupling. It says nothing about whether your vehicle can tow the load. Check the receiver class, then towing capacity, then payload — payload is usually what runs out first.
Common questions
What size hitch ball do I need?
Whatever size your coupler is — the two must match exactly. Most couplers have the required ball size stamped or labelled right on them, so look there first before measuring anything.
The three common sizes are 1-7/8", 2" and 2-5/16", with 3" used on goosenecks. They are close enough in appearance that guessing by eye is genuinely unsafe.
Can I use a 2 inch ball on a 2-5/16 coupler?
No. Never. The socket would close on a ball too small to fill it, leaving a gap above the ball that lets the coupler lift straight off under load. It can look and feel latched and still release.
The reverse does not work either: an oversized ball simply will not latch. There is no acceptable mismatch in either direction.
What does the shank diameter do?
The shank is the threaded stem that passes down through the ball mount and is held by a nut underneath. Its job is to fit the hole in your ball mount. A shank rattling in an oversized hole concentrates load badly and works itself loose.
What it does not do is set the capacity. It is tempting to assume a thicker shank means a higher rating, and this page used to say exactly that, but the manufacturer catalogues disagree: CURT lists a 2" ball on a 1" shank at 12,000 lb, and a 2" ball on a thicker 1-1/4" shank at 10,000 lb. Across the range the high numbers track the heat-treated balls, not the thick-shanked ones. Read the figure stamped on the ball.
Where do I find the ball rating?
Stamped on the top of the ball itself. Every legitimate hitch ball carries its capacity there, and that stamped figure is the one that governs — not this chart, and not the packaging.
If a ball has no stamp, do not use it. An unmarked ball has no traceable rating, and this is a component whose failure separates your trailer from your vehicle at speed.
How tight should the hitch ball nut be?
Tighter than most people expect, and to a number rather than by feel. CURT specifies 160 ft-lb for a 3/4" shank, 250 ft-lb for 1", 450 ft-lb for 1-1/4", and 4,550 ft-lb for the 2" shanks used on 3" gooseneck balls.
Those are dry figures. Leave anti-seize and thread lubricant off the shank unless the ball maker calls for them, because a lubricated thread reaches a much higher clamp load at the same wrench reading, and the number stops meaning what it was set to mean.
Does a bigger ball increase my towing capacity?
No. The ball is one link in a chain that also includes the coupler, ball mount, receiver, vehicle GCWR, payload and axle ratings. Your capacity is the lowest of all of them.
Fitting a 2-5/16" ball rated to 30,000 lb on a half-ton truck changes nothing about what that truck can tow. It just means the ball is no longer the weakest link.
Related tools
- Hitch Class SelectorWhich receiver class covers your trailer weight and tongue weight.
- Tongue Weight CalculatorFind your target tongue weight and check a measured value against the safe range.
- Weight Distribution Hitch CalculatorSee how much load a WD hitch moves back to the front axle, and whether you need one.
Sources
- CURT - Trailer Balls catalogue section (PDF) - every ball listed by diameter, shank diameter, shank length and capacity, plus the torque table; states the balls meet U.S. VESC V-5 requirements
- CURT part 40038 - 2" ball, 1" shank, 12,000 lb - with 40090 below, the pair showing shank diameter does not set capacity
- CURT part 40090 - 2" ball, 1-1/4" shank, 10,000 lb - thicker shank, lower rating, same ball diameter
- CURT Manufacturing - Standard trailer hitch ball sizes - the four standard diameters
- NHTSA - Towing a Trailer: Being Equipped for Safety (DOT HS 809 433)