What is Fillet Weld Capacity Table used for in structural engineering?

Fillet Weld Capacity Table provides values required for steel design calculations including capacity checks, connection design, and detailing. It is referenced in structural design codes and used by practicing engineers during the design of buildings, bridges, and industrial structures.

Can I use these reference values directly in my design?

Yes, provided the values match your governing code edition and project specifications. Always cross-reference against the primary source (code document, manufacturer data, or published standard). The information on this page is for educational use — final verification by a licensed engineer is required.

How often are these reference values updated?

Reference content is maintained to align with current code editions. When a new edition of AISC 360, AS 4100, EN 1993, or CSA S16 is published, values are reviewed and updated. Check the last-modified date at the bottom of the page and verify against the current edition for your jurisdiction.

Fillet Weld Capacity Table | Steel Calculator

| 1/8 | 2/16 | 0.088 | 2.78 | 33.4 | 0.487 | | 3/16 | 3/16 | 0.133 | 4.18 | 50.1 | 0.731 | | 1/4 | 4/16 | 0.177 | 5.57 | 66.9 | 0.975 | | 5/16 | 5/16 | 0.221 | 6.96 | 83.6 | 1.219 | | 3/8 | 6/16 | 0.265 | 8.36 | 100.3 | 1.462 | | 7/16 | 7/16 | 0.309 | 9.75 | 117.0 | 1.706 | | 1/2 | 8/16 | 0.354 | 11.14 | 133.7 | 1.949 | | 9/16 | 9/16 | 0.398 | 12.53 | 150.4 | 2.193 | | 5/8 | 10/16 | 0.442 | 13.93 | 167.1 | 2.437 | | 11/16 | 11/16 | 0.486 | 15.32 | 183.8 | 2.680 | | 3/4 | 12/16 | 0.530 | 16.71 | 200.5 | 2.924 | | 13/16 | 13/16 | 0.575 | 18.10 | 217.2 | 3.167 | | 7/8 | 14/16 | 0.619 | 19.50 | 234.0 | 3.411 | | 15/16 | 15/16 | 0.663 | 20.89 | 250.7 | 3.655 | | 1 | 16/16 | 0.707 | 22.28 | 267.4 | 3.898 |

Most Common Weld Sizes in Practice

Weld Size	Typical Application	phi*Rn kips/in.
3/16 in.	Light gusset connections, min for 3/8-1/2 in. plate	4.18
1/4 in.	Standard beam web connections, typical shop weld	5.57
5/16 in.	Heavy beam connections, column stiffeners	6.96
3/8 in.	Moment connections, column splices	8.36

ASD Allowable Capacity Table — E70XX

Leg Size a (in.)	Rn/Omega kips/in.	Rn/Omega kips/ft.
1/8	1.86	22.3
3/16	2.78	33.4
1/4	3.72	44.6
5/16	4.64	55.7
3/8	5.57	66.9
7/16	6.50	78.0
1/2	7.43	89.2
5/8	9.28	111.4
3/4	11.14	133.7
1	14.86	178.3

Conversion: ASD = LRFD / 1.5 for all values.

Transverse (90-Degree) Loading — 50% Capacity Increase

Leg Size a (in.)	phi*Rn Longitudinal (kips/in.)	phi*Rn Transverse (kips/in.)
1/4	5.57	8.36
5/16	6.96	10.45
3/8	8.36	12.53
1/2	11.14	16.71

Transverse fillet welds are 50% stronger than longitudinal welds. End-plate moment connections benefit from this directional increase.

Metric—Imperial Conversion

Leg Size (mm)	Approx. Imperial	phi*Rn kN/mm	phi*Rn kN/m
3	1/8 in.	0.487	487
5	3/16 in.	0.811	811
6	1/4 in.	0.975	975
8	5/16 in.	1.299	1299
10	3/8 in.	1.624	1624
12	1/2 in.	1.949	1949
16	5/8 in.	2.599	2599
20	3/4 in.	3.249	3249
25	1 in.	4.061	4061

Electrode Comparison

Electrode	F_EXX (ksi)	phi*Rn for 1/4 in. weld (kips/in.)	Relative to E70XX
E60XX	60	4.78	86%
E70XX	70	5.57	100%
E80XX	80	6.36	114%
E90XX	90	7.16	129%
E100XX	100	7.96	143%
E110XX	110	8.75	157%

Higher-strength electrodes (E80XX+) provide proportionally higher capacity but are rarely justified — base metal shear typically governs before E70XX weld metal.

Base Metal Shear — The Governing Limit

Fillet weld capacity is an upper bound. Base metal shear rupture often governs:

phi*Rn_base = phi x 0.60 x Fu x t (AISC J4.2)

Base Metal	Fu (ksi)	phi*Rn for 3/8 in. plate (kips/in.)
A36	58	9.79
A572 Gr 50	65	10.97
A992	65	10.97

Always compare phiRn_weld to phiRn_base. The lesser value governs.

Multi-Code Comparison — AISC vs AS 4100 vs EN 1993

Parameter	AISC 360 (US)	AS 4100 (Australia)	EN 1993-1-8 (Europe)
Resistance factor	0.75	0.80	gamma_M2 = 1.25 (approx 0.80)
Capacity 6 mm weld	0.975 kN/mm	1.04 kN/mm	0.936 kN/mm
Capacity 8 mm weld	1.30 kN/mm	1.38 kN/mm	1.25 kN/mm

Worked Example — Weld Size for Shear Connection

Problem: Double-angle shear connection transfers Vu = 95 kips through 4 vertical fillet welds, each 12 in. long (48 in. total). Find required E70XX weld size.

Step 1: Required phi*Rn = 95 / 48 = 1.98 kips/in.

Step 2: Table lookup: 1/8 in. weld = 2.78 kips/in. — OK for strength.

Step 3: Minimum per Table J2.4: Column flange 5/8 in. requires 1/4 in. minimum.

Step 4: Minimum governs. Specify 1/4 in. fillet weld, total capacity 267 kips.

Step 5: Base metal check: 3/8 in. A36 angle phi*Rn = 9.79 kips/in. — does not govern.

Result: 1/4 in. fillet weld, E70XX electrodes, 12 in. long each.

Frequently Asked Questions

What is the capacity of a 1/4 inch fillet weld per inch of length? A 1/4 in. fillet weld with E70XX provides phi*Rn = 5.57 kips/in. (LRFD). Per foot: 66.9 kips. ASD: 3.72 kips/in. Metric: 6 mm E49XX fillet = 0.975 kN/mm.

How is fillet weld capacity calculated? Capacity uses effective throat E = 0.707 x leg size a. phiRn = 0.75 x 0.60 x F_EXX x E. For E70XX: phiRn = 22.27 x a kips/in.

What electrode for A992 steel? E70XX electrodes are standard. AISC J2.4 explicitly permits undermatched electrodes.

What is the difference between LRFD and ASD? LRFD phi = 0.75; ASD Omega = 2.00. ASD = LRFD / 1.5.

How to account for weld loading angle? Multiply by (1.0 + 0.50 x sin^1.5 theta). Transverse (90 deg) = 1.5x capacity increase.

Can weld capacity exceed base metal strength? Yes, and this is critical. Always compare to phi x 0.60 x Fu x t. Base metal shear often governs for thick plates.

Run This Calculation

Try it now: Calculate your fillet weld capacity with our free Welded Connection calculator

Educational reference only. Verify against AISC 360-22 Section J2.4 and governing project specification.