Summary

Package Max power Length Width
01005 31 mW 0.40 0.20
0201 50 mW 0.60 0.30
0402 60 mW 1.00 0.50
0603 60 mW 1.60 0.80
0805 100 mW 2.00 1.25
1206 125 mW 3.20 1.60
1210 250 mW 3.20 2.50
1812 250 mW 4.50 3.20
2010 250 mW 5.00 2.50
2512 500 mW 6.40 3.20

Data from Panasonic thick film chip resistors and Electronic-notes.