The Chicago Black Hawks have the worst winning percentage by a team with more than 0 championships in a season, winning 38.5 percent of the time in 1937-38.

lowest winning percentage by a NHL champion in a regular season team

	TEAM	W%	CHAMPS	SEASON	GP	W	L	T	OTL	PTS	PTS%	SOW	SOL	G	GA	DIFF	PP%	PK%	S/GP	S%	SA/GP	SV%
1	Black Hawks	.385	1	1937-38	48	14	25	9		37	.385			97	139	-42
2	Maple Leafs	.475	1	1948-49	60	22	25	13		57	.475			147	161	-14
3	Kings	.488	1	2011-12	82	40	27		15	95	.579	6	9	188	170	18	17.0	87.0	30.60	7.5	27.41	.924
4	Maple Leafs	.520	1	1944-45	50	24	22	4		52	.520			183	161	22
5	Black Hawks	.531	1	1933-34	48	20	17	11		51	.531			88	83	5
6	Rangers	.534	1	1927-28	44	19	16	9		47	.534			94	79	15
7	Maple Leafs	.536	1	1966-67	70	32	27	11		75	.536			204	211	-7			31.24	9.3	34.39	.912
8	Black Hawks	.536	1	1960-61	70	29	24	17		75	.536			198	180	18			31.16	9.1	31.51	.918
9	Canadiens	.536	1	1952-53	70	28	23	19		75	.536			155	148	7
10	Devils	.542	1	1994-95	48	22	18	8		52	.542			136	121	15	13.4	81.2	30.08	9.4	25.38	.901
11	Canadiens	.542	1	1923-24	24	13	11	0		26	.542			59	48	11
12	Penguins	.544	1	1991-92	80	39	32	9		87	.544			343	308	35	21.7	79.9	31.78	13.5	31.48	.878
13	Canadiens	.544	1	1985-86	80	40	33	7		87	.544			330	280	50	25.2	79.4	29.43	14.0	27.11	.871
14	Blues	.549	1	2018-19	82	45	28		9	99	.604	3	3	244	220	24	21.1	81.5	31.76	9.4	28.60	.906
15	Penguins	.549	1	2008-09	82	45	28		9	99	.604	6	6	258	233	25	17.2	82.7	29.04	10.8	30.29	.906
16	Penguins	.550	1	1990-91	80	41	33	6		88	.550			342	305	37	22.9	79.2	30.20	14.2	34.04	.888
17	Maroons	.552	1	1934-35	48	24	19	5		53	.552			123	92	31
18	Maple Leafs	.552	1	1931-32	48	23	18	7		53	.552			155	127	28
19	Maple Leafs	.557	1	1963-64	70	33	25	12		78	.557			192	172	20			32.13	8.5	30.79	.920
20	Kings	.561	1	2013-14	82	46	28		8	100	.610	8	6	198	168	30	15.1	83.1	31.65	7.6	26.21	.922
21	Bruins	.561	1	2010-11	82	46	25		11	103	.628	2	6	244	189	55	16.2	82.6	32.88	9.1	32.71	.930
22	Oilers	.563	1	1989-90	80	38	28	14		90	.563			315	283	32	20.6	80.3	28.15	14.0	29.06	.878
23	Rangers	.563	1	1932-33	48	23	17	8		54	.563			135	107	28
24	St. Patricks	.563	1	1921-22	24	13	10	1		27	.563			98	97	1
25	Islanders	.569	1	1979-80	80	39	28	13		91	.569			281	247	34	23.4	77.6	27.71	12.7	29.95	.897