Ring Terminal Size Chart: Wire Gauge, Stud Size and Color Code

October 02, 2026

A ring terminal is sized by two numbers: the wire gauge range its barrel crimps onto, and the stud size its ring fits over. Get both right and the connection is tight, cool-running and hard to pull off. Get either wrong and you get a crimp that slips or a ring that rocks on the screw. On insulated terminals the color tells you the wire range at a glance: red = 22–18 AWG, blue = 16–14 AWG, yellow = 12–10 AWG.

The charts below cover every ring terminal and copper lug we stock, from 22 AWG signal wire up to 4/0 battery cable, with links straight to each size. All are tin-plated copper unless noted, and every one is sold by the piece, so you can order exactly the sizes your job needs.

Ring terminal color code by wire gauge

Insulated ring terminals use the same color code on vinyl, nylon and heat shrink sleeves, so you can match terminal to wire without reading the package. The heavier sizes repeat the same three colors.

Always check the wire size printed on the jacket rather than guessing from how thick the wire looks. Insulation thickness varies, and a terminal one size too large will not crimp tightly. If you are still choosing the wire itself, our automotive wire size guide covers amperage and voltage drop.

Ring terminal stud size chart

The stud size is the screw or bolt the ring goes over. Small sizes use machine-screw numbers (#4 to #10), and larger sizes are fractions of an inch. Pick the ring that matches the stud exactly. An oversized ring touches the stud on only one side, which cuts contact area and lets the terminal shift as the nut is tightened.

*Metric matches are approximate. Ring hole diameters vary slightly by manufacturer, so test-fit when crossing between inch and metric hardware.

How to measure: if the screw isn't marked, measure its outside thread diameter with calipers and pick the closest row above. Do not drill out a ring that is too small; it removes the metal that carries the current. Choose the next stud size instead.

Ring terminal sizes we stock: 22–10 AWG

Click any stud size to go straight to that terminal. Prices start at a few cents each.

22-18 AWG ring terminals (red)

16-14 AWG ring terminals (blue)

12-10 AWG ring terminals (yellow)

Heavy-gauge ring terminals and lugs: 8 AWG to 4/0

For battery, starter, inverter and winch cable, you have three choices. Insulated ring terminals (8–4 AWG) have a built-in sleeve. Brazed non-insulated terminals cost less. Seamless tinned copper lugs are the usual choice for fine-strand battery and welding cable. Finish bare terminals and lugs with adhesive-lined dual wall heat shrink.

Sizing battery cable first? See how to size marine battery cable, then match the lug to the cable and the stud on your battery or switch. Shop all tinned copper lugs and battery cable.

Vinyl vs nylon vs heat shrink: which ring terminal type?

Once wire size and stud are set, the insulation type is about where the terminal lives:

All of our standard ring terminals are tin-plated copper with a brazed barrel and are rated 600V. High-temperature terminals are nickel-plated steel, built for heat rather than conductivity. Use them only where standard terminals would fail.

How to choose a ring terminal in three steps

1. Match the wire. Read the AWG on the wire jacket and pick the range that includes it: red, blue or yellow for 22–10 AWG, or the exact gauge for 8 AWG and up. Ring terminals are made for stranded copper wire.
2. Match the stud. Identify the screw or post size (#4–#10, or 1/4" to 1/2") and use the same ring size. Not sure? Measure the thread diameter and use the stud chart above.
3. Match the environment. Vinyl for dry indoor work, nylon for vibration, heat shrink for anywhere wet, and high-temp for heat. Need to remove the connection without taking the screw out? A spade (fork) terminal slides under a loosened screw instead.

Crimp tip: use a crimper with dies marked for the terminal color or gauge, then give the wire a firm pull. A good crimp will not move. On heavy lugs, use a hex crimper sized to the cable. Uneven pressure from a hammer-style tool leaves gaps that heat up under load.

Ring terminal size FAQ

What size ring terminal do I need for 10 AWG wire?

A yellow 12–10 AWG ring terminal. Choose the ring size that matches your stud — we stock 12–10 AWG rings from #6 to 1/2".

What size ring terminal for 14 or 16 AWG wire?

A blue 16–14 AWG ring terminal. It covers both 16 and 14 AWG stranded wire.

What does #8 or #10 mean on a ring terminal?

It is the screw size the ring fits: #8 fits a #8 screw (0.164") and #10 fits a #10 screw (0.190"). Bigger numbers mean bigger screws, up to #10. After that, sizes are given in fractions of an inch.

Can I use a larger ring than the stud?

It will fit, but it will not seat flat or carry current as well. A ring that matches the stud gives the most contact area and keeps the terminal from shifting as you tighten the nut.

Can I use a 22–18 AWG terminal on 14 AWG wire?

No. The barrel is too small to accept the wire properly. Use the blue 16–14 AWG size. Likewise, a 12–10 barrel on 18 AWG wire will not crimp tightly.

Ring terminal or copper lug for battery cable?

Both work. Seamless tinned copper lugs are the common choice for flexible battery and welding cable. Brazed ring terminals cost less, and insulated 8–4 AWG terminals save you a heat shrink step.

Are ring terminals waterproof?

Only heat shrink ring terminals are sealed. Their adhesive-lined sleeve melts around the wire insulation when heated. For other types, add adhesive-lined heat shrink tubing over the barrel.

Wiring a trailer? Our trailer brake wiring guide shows where each terminal goes. Browse every size in ring terminals, or see all terminals and connectors.

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