calc() as CSS unit value

Method of allowing calculated values for length units, i.e. width: calc(100% - 3em)

Spec	https://w3c.github.io/csswg-drafts/css-values-3/#calc-notation
Status	W3C Candidate Recommendation

IE	Edge	Firefox	Chrome	Safari	Opera
		147	144
		146	143	TP
		145	142	26.1
11 (3)	141	144	141	26.0	122
10 (3)	140	143	140	18.5-18.6	121
9 (2)	139	142	139	18.4	120
8	138	141	138	18.3	119
Show all
7	137	140	137	18.2	118
6	136	139	136	18.1	117
5.5	135	138	135	18.0	116
	134	137	134	17.6	115
	133	136	133	17.5	114
	132	135	132	17.4	113
	131	134	131	17.3	112
	130	133	130	17.2	111
	129	132	129	17.1	110
	128	131	128	17.0	109
	127	130	127	16.6	108
	126	129	126	16.5	107
	125	128	125	16.4	106
	124	127	124	16.3	105
	123	126	123	16.2	104
	122	125	122	16.1	103
	121	124	121	16.0	102
	120	123	120	15.6	101
	119	122	119	15.5	100
	118	121	118	15.4	99
	117	120	117	15.2-15.3	98
	116	119	116	15.1	97
	115	118	115	15	96
	114	117	114	14.1	95
	113	116	113	14	94
	112	115	112	13.1	93
	111	114	111	13	92
	110	113	110	12.1	91
	109	112	109	12	90
	108	111	108	11.1	89
	107	110	107	11	88
	106	109	106	10.1	87
	105	108	105	10	86
	104	107	104	9.1	85
	103	106	103	9	84
	102	105	102	8	83
	101	104	101	7.1	82
	100	103	100	7	81
	99	102	99	6.1	80
	98	101	98	6 (*)	79
	97	100	97	5.1	78
	96	99	96	5	77
	95	98	95	4	76
	94	97	94	3.2	75
	93	96	93	3.1	74
	92	95	92		73
	91	94	91		72
	90	93	90		71
	89	92	89		70
	88	91	88		69
	87	90	87		68
	86	89	86		67
	85	88	85		66
	84	87	84		65
	83	86	83		64
	81	85	81		63
	80	84	80		62
	79	83	79		60
	18	82	78		58
	17	81	77		57
	16	80	76		56
	15	79	75		55
	14	78	74		54
	13	77	73		53
	12	76	72		52
		75	71		51
		74	70		50
		73	69		49
		72	68		48
		71	67		47
		70	66		46
		69	65		45
		68	64		44
		67	63		43
		66	62		42
		65	61		41
		64	60		40
		63	59		39
		62	58		38
		61	57		37
		60	56		36
		59	55		35
		58	54		34
		57	53		33
		56	52		32
		55	51		31
		54	50		30
		53	49		29
		52	48		28
		51	47		27
		50	46		26
		49	45		25
		48	44		24
		47	43		23
		46	42		22
		45	41		21
		44	40		20
		43	39		19
		42	38		18
		41	37		17
		40	36		16
		39	35		15
		38	34		12.1
		37	33		12
		36	32		11.6
		35	31		11.5
		34	30		11.1
		33	29		11
		32	28		10.6
		31	27		10.5
		30	26		10.0-10.1
		29	25 (*)		9.5-9.6
		28	24 (*)		9
		27	23 (*)
		26	22 (*)
		25	21 (*)
		24	20 (*)
		23	19 (*)
		22	18
		21	17
		20	16
		19	15
		18	14
		17	13
		16	12
		15 (*)	11
		14 (*)	10
		13 (*)	9
		12 (*)	8
		11 (*)	7
		10 (*)	6
		9 (*)	5
		8 (*)	4
		7 (*)
		6 (*)
		5 (*)
		4 (*)
		3.6
		3.5
		3
		2

Safari on iOS	Opera Mini	Android Browser	Blackberry Browser	Opera Mobile	Android Chrome	Android Firefox	IE Mobile	Android UC Browser	Samsung Internet	QQ Browser	Baidu Browser	KaiOS Browser
26.1
26.0	all	141	10	80	141	143	11	15.5	28	14.9	13.52	3.0-3.1
18.5-18.6		4.4.3-4.4.4 (1)	7	12.1			10		27			2.5
18.4		4.4 (1)		12					26
18.3		4.2-4.3		11.5					25
Show all
18.2		4.1		11.1					24
18.1		4		11					23
18.0		3		10					22
17.6-17.7		2.3							21
17.5		2.2							20
17.4		2.1							19.0
17.3									18.0
17.2									17.0
17.1									16.0
17.0									15.0
16.6-16.7									14.0
16.5									13.0
16.4									12.0
16.3									11.1-11.2
16.2									10.1
16.1									9.2
16.0									8.2
15.6-15.8									7.2-7.4
15.5									6.2-6.4
15.4									5.0-5.4
15.2-15.3									4
15.0-15.1
14.5-14.8
14.0-14.4
13.4-13.7
13.3
13.2
13.0-13.1
12.2-12.5
12.0-12.1
11.3-11.4
11.0-11.2
10.3
10.0-10.2
9.3
9.0-9.2
8.1-8.4
8
7.0-7.1
6.0-6.1 (*)
5.0-5.1
4.2-4.3
4.0-4.1
3.2

Notes

Support can be somewhat emulated in older versions of IE using the non-standard expression() syntax.

Due to the way browsers handle sub-pixel rounding differently, layouts using calc() expressions may have unexpected results.

1. Partial support in Android Browser 4.4 refers to the browser lacking the ability to multiply and divide values.

2. Partial support in IE9 refers to the browser crashing when used as a background-position value.

3. Partial support in IE10/IE11 refers to calc not working properly with various use cases mentioned in known issues

^* Partial support with prefix.

Bugs

• IE 9 - 11 and Edge do not support width: calc() on table cells. Bug Report

• IE 9 - 11 don't render box-shadow when calc() is used for any of the values

• IE10 crashes when a div with a property using calc() has a child with same property with inherit.

• IE10, IE11, and Edge < 14 don't support using calc() inside a transform. Bug report

• IE11 is reported to have trouble with calc() with nested expressions, e.g. width: calc((100% - 10px) / 3); (i.e. it rounds differently)

• IE11 is reported to not support calc() correctly in generated content

• IE11 does not support transitioning values set with calc()

• Safari & iOS Safari (both 6 and 7) does not support viewport units (vw, vh, etc) in calc().

• IE & Edge are reported to not support calc inside a 'flex'. (Not tested on older versions)
  This example does not work: flex: 1 1 calc(50% - 20px);

• IE does not support calc() on color functions. Example: color: hsl(calc(60 * 2), 100%, 50%).

• Firefox <48 does not support calc() inside the line-height, stroke-width, stroke-dashoffset, and stroke-dasharray properties. Bug report

• Firefox <59 does not support calc() on color functions. Example: color: hsl(calc(60 * 2), 100%, 50%). Bug Report

• Firefox <66 does not support width: calc() on table cells. Bug Report

Resources

• Mozilla Hacks article
• MDN Web Docs - calc
• WebPlatform Docs