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Glossary » Beams » Simply Supported » Uniformly Distributed Load » Four Equal Spans » Wide Flange Steel I Beam » W21 × 44
Wide Flange Steel I Beam | Single Span | Two Equal Spans | Three Equal Spans | Four Equal Spans

For a simply supported beam in four equal spans, we compute the displacement at the middle of the first and fourth spans, and the maximum normal stress stress_max occuring at the second and fourth supports of the beam.
The tabulated data listed in this page are calculated based on the area moment of inertia (Ixx = 843 in4) for the W21 × 44 Wide Flange Steel I Beam and the typical Young's modulus (E = 3.046 × 107 psi) of steels. Note that the typical yielding stress Yield of steels can range from 1.015 × 104 to 2.970 × 105 psi. The purpose of this page is to give a rough estimation of the load-bearing capacity of this particular beam, rather than a guideline for designing actual building structures. Please check your local building codes for regulatory requirements.
Note: The weight of the beam itself is not included in the calculation.
L = 3 ft
L = 5 ft
L = 10 ft
L = 15 ft
L = 20 ft
L = 25 ft
L = 30 ft
L = 40 ft
L = 50 ft
L = 60 ft
L = 70 ft
L = 80 ft
L = 90 ft
L = 100 ft
L = 125 ft
L = 150 ft
   
Steel I Beam: W21 × 44 (Wide Flange 21 inch tall × 44 lbf/ft)
L = 3.00 ft
P (lbf/ft) w_max (in) stress_max (psi)
44.0 1.51 × 10-6 6.24
50.0 1.72 × 10-6 7.09
60.0 2.06 × 10-6 8.50
70.0 2.40 × 10-6 9.92
80.0 2.75 × 10-6 11.3
90.0 3.09 × 10-6 12.8
100 3.43 × 10-6 14.2
200 6.87 × 10-6 28.3
300 1.03 × 10-5 42.5
400 1.37 × 10-5 56.7
500 1.72 × 10-5 70.9
600 2.06 × 10-5 85.0
700 2.40 × 10-5 99.2
800 2.75 × 10-5 113
900 3.09 × 10-5 128
1000 3.43 × 10-5 142
2000 6.87 × 10-5 283
3000 1.03 × 10-4 425
4000 1.37 × 10-4 567
5000 1.72 × 10-4 709
6000 2.06 × 10-4 850
7000 2.40 × 10-4 992
8000 2.75 × 10-4 1130
9000 3.09 × 10-4 1280
1.00 × 104 3.43 × 10-4 1420
2.00 × 104 6.87 × 10-4 2830
3.00 × 104 0.00103 4250
4.00 × 104 0.00137 5670
5.00 × 104 0.00172 7090
6.00 × 104 0.00206 8500
7.00 × 104 0.00240 9920
8.00 × 104 0.00275 1.13 × 104
9.00 × 104 0.00309 1.28 × 104
1.00 × 105 0.00343 1.42 × 104
2.00 × 105 0.00687 2.83 × 104
3.00 × 105 0.0103 4.25 × 104
4.00 × 105 0.0137 5.67 × 104
5.00 × 105 0.0172 7.09 × 104
6.00 × 105 0.0206 8.50 × 104
7.00 × 105 0.0240 9.92 × 104
8.00 × 105 0.0275 1.13 × 105
9.00 × 105 0.0309 1.28 × 105
1.00 × 106 0.0343 1.42 × 105
2.00 × 106 0.0687 2.83 × 105
2.10 × 106 0.0720 2.97 × 105
Steel I Beam: W21 × 44 (Wide Flange 21 inch tall × 44 lbf/ft)
L = 5.00 ft
P (lbf/ft) w_max (in) stress_max (psi)
44.0 1.17 × 10-5 17.3
50.0 1.32 × 10-5 19.7
60.0 1.59 × 10-5 23.6
70.0 1.85 × 10-5 27.6
80.0 2.12 × 10-5 31.5
90.0 2.38 × 10-5 35.4
100 2.65 × 10-5 39.4
200 5.30 × 10-5 78.7
300 7.95 × 10-5 118
400 1.06 × 10-4 157
500 1.32 × 10-4 197
600 1.59 × 10-4 236
700 1.85 × 10-4 276
800 2.12 × 10-4 315
900 2.38 × 10-4 354
1000 2.65 × 10-4 394
2000 5.30 × 10-4 787
3000 7.95 × 10-4 1180
4000 0.00106 1570
5000 0.00132 1970
6000 0.00159 2360
7000 0.00185 2760
8000 0.00212 3150
9000 0.00238 3540
1.00 × 104 0.00265 3940
2.00 × 104 0.00530 7870
3.00 × 104 0.00795 1.18 × 104
4.00 × 104 0.0106 1.57 × 104
5.00 × 104 0.0132 1.97 × 104
6.00 × 104 0.0159 2.36 × 104
7.00 × 104 0.0185 2.76 × 104
8.00 × 104 0.0212 3.15 × 104
9.00 × 104 0.0238 3.54 × 104
1.00 × 105 0.0265 3.94 × 104
2.00 × 105 0.0530 7.87 × 104
3.00 × 105 0.0795 1.18 × 105
4.00 × 105 0.106 1.57 × 105
5.00 × 105 0.132 1.97 × 105
6.00 × 105 0.159 2.36 × 105
7.00 × 105 0.185 2.76 × 105
7.54 × 105 0.200 2.97 × 105
Steel I Beam: W21 × 44 (Wide Flange 21 inch tall × 44 lbf/ft)
L = 10.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
44.0 1.87 × 10-4 69.3
50.0 2.12 × 10-4 78.7
60.0 2.54 × 10-4 94.5
70.0 2.97 × 10-4 110
80.0 3.39 × 10-4 126
90.0 3.82 × 10-4 142
100 4.24 × 10-4 157
200 8.48 × 10-4 315
300 0.00127 472
400 0.00170 630
500 0.00212 787
600 0.00254 945
700 0.00297 1100
800 0.00339 1260
900 0.00382 1420
1000 0.00424 1570
2000 0.00848 3150
3000 0.0127 4720
4000 0.0170 6300
5000 0.0212 7870
6000 0.0254 9450
7000 0.0297 1.10 × 104
8000 0.0339 1.26 × 104
9000 0.0382 1.42 × 104
1.00 × 104 0.0424 1.57 × 104
2.00 × 104 0.0848 3.15 × 104
3.00 × 104 0.127 4.72 × 104
4.00 × 104 0.170 6.30 × 104
5.00 × 104 0.212 7.87 × 104
6.00 × 104 0.254 9.45 × 104
7.00 × 104 0.297 1.10 × 105
8.00 × 104 0.339 1.26 × 105
9.00 × 104 0.382 1.42 × 105
1.00 × 105 0.424 1.57 × 105
1.89 × 105 0.800 2.97 × 105
Steel I Beam: W21 × 44 (Wide Flange 21 inch tall × 44 lbf/ft)
L = 15.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
44.0 9.44 × 10-4 156
50.0 0.00107 177
60.0 0.00129 213
70.0 0.00150 248
80.0 0.00172 283
90.0 0.00193 319
100 0.00215 354
200 0.00429 709
300 0.00644 1060
400 0.00859 1420
500 0.0107 1770
600 0.0129 2130
700 0.0150 2480
800 0.0172 2830
900 0.0193 3190
1000 0.0215 3540
2000 0.0429 7090
3000 0.0644 1.06 × 104
4000 0.0859 1.42 × 104
5000 0.107 1.77 × 104
6000 0.129 2.13 × 104
7000 0.150 2.48 × 104
8000 0.172 2.83 × 104
9000 0.193 3.19 × 104
1.00 × 104 0.215 3.54 × 104
2.00 × 104 0.429 7.09 × 104
3.00 × 104 0.644 1.06 × 105
4.00 × 104 0.859 1.42 × 105
5.00 × 104 1.07 1.77 × 105
6.00 × 104 1.29 2.13 × 105
7.00 × 104 1.50 2.48 × 105
8.00 × 104 1.72 2.83 × 105
8.38 × 104 1.80 2.97 × 105
Steel I Beam: W21 × 44 (Wide Flange 21 inch tall × 44 lbf/ft)
L = 20.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
44.0 0.00298 277
50.0 0.00339 315
60.0 0.00407 378
70.0 0.00475 441
80.0 0.00543 504
90.0 0.00611 567
100 0.00678 630
200 0.0136 1260
300 0.0204 1890
400 0.0271 2520
500 0.0339 3150
600 0.0407 3780
700 0.0475 4410
800 0.0543 5040
900 0.0611 5670
1000 0.0678 6300
2000 0.136 1.26 × 104
3000 0.204 1.89 × 104
4000 0.271 2.52 × 104
5000 0.339 3.15 × 104
6000 0.407 3.78 × 104
7000 0.475 4.41 × 104
8000 0.543 5.04 × 104
9000 0.611 5.67 × 104
1.00 × 104 0.678 6.30 × 104
2.00 × 104 1.36 1.26 × 105
3.00 × 104 2.04 1.89 × 105
4.00 × 104 2.71 2.52 × 105
4.72 × 104 3.20 2.97 × 105
Steel I Beam: W21 × 44 (Wide Flange 21 inch tall × 44 lbf/ft)
L = 25.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
44.0 0.00729 433
50.0 0.00828 492
60.0 0.00994 591
70.0 0.0116 689
80.0 0.0132 787
90.0 0.0149 886
100 0.0166 984
200 0.0331 1970
300 0.0497 2950
400 0.0662 3940
500 0.0828 4920
600 0.0994 5910
700 0.116 6890
800 0.132 7870
900 0.149 8860
1000 0.166 9840
2000 0.331 1.97 × 104
3000 0.497 2.95 × 104
4000 0.662 3.94 × 104
5000 0.828 4.92 × 104
6000 0.994 5.91 × 104
7000 1.16 6.89 × 104
8000 1.32 7.87 × 104
9000 1.49 8.86 × 104
1.00 × 104 1.66 9.84 × 104
2.00 × 104 3.31 1.97 × 105
3.00 × 104 4.97 2.95 × 105
3.02 × 104 5.00 2.97 × 105
Steel I Beam: W21 × 44 (Wide Flange 21 inch tall × 44 lbf/ft)
L = 30.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
44.0 0.0151 624
50.0 0.0172 709
60.0 0.0206 850
70.0 0.0240 992
80.0 0.0275 1130
90.0 0.0309 1280
100 0.0343 1420
200 0.0687 2830
300 0.103 4250
400 0.137 5670
500 0.172 7090
600 0.206 8500
700 0.240 9920
800 0.275 1.13 × 104
900 0.309 1.28 × 104
1000 0.343 1.42 × 104
2000 0.687 2.83 × 104
3000 1.03 4.25 × 104
4000 1.37 5.67 × 104
5000 1.72 7.09 × 104
6000 2.06 8.50 × 104
7000 2.40 9.92 × 104
8000 2.75 1.13 × 105
9000 3.09 1.28 × 105
1.00 × 104 3.43 1.42 × 105
2.00 × 104 6.87 2.83 × 105
2.10 × 104 7.20 2.97 × 105
Steel I Beam: W21 × 44 (Wide Flange 21 inch tall × 44 lbf/ft)
L = 40.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
44.0 0.0478 1110
50.0 0.0543 1260
60.0 0.0651 1510
70.0 0.0760 1760
80.0 0.0868 2020
90.0 0.0977 2270
100 0.109 2520
200 0.217 5040
300 0.326 7560
400 0.434 1.01 × 104
500 0.543 1.26 × 104
600 0.651 1.51 × 104
700 0.760 1.76 × 104
800 0.868 2.02 × 104
900 0.977 2.27 × 104
1000 1.09 2.52 × 104
2000 2.17 5.04 × 104
3000 3.26 7.56 × 104
4000 4.34 1.01 × 105
5000 5.43 1.26 × 105
6000 6.51 1.51 × 105
7000 7.60 1.76 × 105
8000 8.68 2.02 × 105
9000 9.77 2.27 × 105
1.00 × 104 10.9 2.52 × 105
1.18 × 104 12.8 2.97 × 105
Steel I Beam: W21 × 44 (Wide Flange 21 inch tall × 44 lbf/ft)
L = 50.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
44.0 0.117 1730
50.0 0.132 1970
60.0 0.159 2360
70.0 0.185 2760
80.0 0.212 3150
90.0 0.238 3540
100 0.265 3940
200 0.530 7870
300 0.795 1.18 × 104
400 1.06 1.57 × 104
500 1.32 1.97 × 104
600 1.59 2.36 × 104
700 1.85 2.76 × 104
800 2.12 3.15 × 104
900 2.38 3.54 × 104
1000 2.65 3.94 × 104
2000 5.30 7.87 × 104
3000 7.95 1.18 × 105
4000 10.6 1.57 × 105
5000 13.2 1.97 × 105
6000 15.9 2.36 × 105
7000 18.5 2.76 × 105
7540 20.0 2.97 × 105
Steel I Beam: W21 × 44 (Wide Flange 21 inch tall × 44 lbf/ft)
L = 60.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
44.0 0.242 2490
50.0 0.275 2830
60.0 0.330 3400
70.0 0.385 3970
80.0 0.440 4540
90.0 0.495 5100
100 0.549 5670
200 1.10 1.13 × 104
300 1.65 1.70 × 104
400 2.20 2.27 × 104
500 2.75 2.83 × 104
600 3.30 3.40 × 104
700 3.85 3.97 × 104
800 4.40 4.54 × 104
900 4.95 5.10 × 104
1000 5.49 5.67 × 104
2000 11.0 1.13 × 105
3000 16.5 1.70 × 105
3760 20.7 2.13 × 105
Steel I Beam: W21 × 44 (Wide Flange 21 inch tall × 44 lbf/ft)
L = 70.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
44.0 0.448 3400
50.0 0.509 3860
60.0 0.611 4630
70.0 0.713 5400
80.0 0.814 6170
90.0 0.916 6950
100 1.02 7720
200 2.04 1.54 × 104
300 3.05 2.32 × 104
400 4.07 3.09 × 104
500 5.09 3.86 × 104
600 6.11 4.63 × 104
700 7.13 5.40 × 104
800 8.14 6.17 × 104
900 9.16 6.95 × 104
1000 10.2 7.72 × 104
2000 20.4 1.54 × 105
2030 20.7 1.57 × 105
Steel I Beam: W21 × 44 (Wide Flange 21 inch tall × 44 lbf/ft)
L = 80.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
44.0 0.764 4430
50.0 0.868 5040
60.0 1.04 6050
70.0 1.22 7060
80.0 1.39 8060
90.0 1.56 9070
100 1.74 1.01 × 104
200 3.47 2.02 × 104
300 5.21 3.02 × 104
400 6.95 4.03 × 104
500 8.68 5.04 × 104
600 10.4 6.05 × 104
700 12.2 7.06 × 104
800 13.9 8.06 × 104
900 15.6 9.07 × 104
1000 17.4 1.01 × 105
1190 20.7 1.20 × 105
Steel I Beam: W21 × 44 (Wide Flange 21 inch tall × 44 lbf/ft)
L = 90.0 ft
P (lbf/ft) w_max (in) stress_max (psi)
44.0 1.22 5610
50.0 1.39 6380
60.0 1.67 7650
70.0 1.95 8930
80.0 2.23 1.02 × 104
90.0 2.50 1.15 × 104
100 2.78 1.28 × 104
200 5.56 2.55 × 104
300 8.35 3.83 × 104
400 11.1 5.10 × 104
500 13.9 6.38 × 104
600 16.7 7.65 × 104
700 19.5 8.93 × 104
743 20.7 9.47 × 104
Steel I Beam: W21 × 44 (Wide Flange 21 inch tall × 44 lbf/ft)
L = 100 ft
P (lbf/ft) w_max (in) stress_max (psi)
44.0 1.87 6930
50.0 2.12 7870
60.0 2.54 9450
70.0 2.97 1.10 × 104
80.0 3.39 1.26 × 104
90.0 3.82 1.42 × 104
100 4.24 1.57 × 104
200 8.48 3.15 × 104
300 12.7 4.72 × 104
400 17.0 6.30 × 104
487 20.7 7.67 × 104
Steel I Beam: W21 × 44 (Wide Flange 21 inch tall × 44 lbf/ft)
L = 125 ft
P (lbf/ft) w_max (in) stress_max (psi)
44.0 4.55 1.08 × 104
50.0 5.18 1.23 × 104
60.0 6.21 1.48 × 104
70.0 7.25 1.72 × 104
80.0 8.28 1.97 × 104
90.0 9.32 2.21 × 104
100 10.4 2.46 × 104
200 20.7 4.91 × 104
Steel I Beam: W21 × 44 (Wide Flange 21 inch tall × 44 lbf/ft)
L = 150 ft
P (lbf/ft) w_max (in) stress_max (psi)
44.0 9.44 1.56 × 104
50.0 10.7 1.77 × 104
60.0 12.9 2.13 × 104
70.0 15.0 2.48 × 104
80.0 17.2 2.83 × 104
90.0 19.3 3.19 × 104
96.3 20.7 3.41 × 104
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