Common Computer Monitor Sizes and Aspect Ratio Conversion Table (Diagonal Size Reference Table)

Common computer monitor sizes include 17 inches, 24 inches, 32 inches, and so on. This number refers to the diagonal size of the screen. However, each computer monitor has a different display ratio, so even monitors of the same size will differ in size because of different aspect ratios.

Although the following calculates common monitor sizes and aspect ratios to produce a detailed length-width conversion table (reference table), please note that the values are presented to two decimal places and are not truly precise figures (nor do I think precision beyond the third decimal place offers any benefit to ordinary users). In addition, some manufacturers cut corners when labeling monitor sizes—for example, labeling 23.5 inches as 24 inches is common—so the precise panel length and width for each computer monitor size should still be based on the specification sheet!

Common Computer Monitor Sizes and Aspect Ratio Conversion Table (Diagonal Size Reference Table)

Screen Size / Aspect Ratio	4:3	5:4	16:9	16:10	21:9
17 in	34.54 × 25.91	33.72 × 26.97	37.63 × 21.17	36.62 × 22.89	39.69 × 17.01
19 in	38.61 × 28.96	37.68 × 30.15	42.06 × 23.66	40.92 × 25.58	44.36 × 19.01
20 in	40.64 × 30.48	39.67 × 31.73	44.28 × 24.91	43.08 × 26.92	46.69 × 20.01
22 in	44.70 × 33.53	43.63 × 34.91	48.70 × 27.40	47.39 × 29.62	51.36 × 22.01
23 in	46.74 × 35.05	45.62 × 36.49	50.92 × 28.64	49.54 × 30.96	53.70 × 23.01
24 in	48.77 × 36.58	47.60 × 38.08	53.13 × 29.89	51.69 × 32.31	56.03 × 24.01
25 in	50.80 × 38.10	49.59 × 39.67	55.35 × 31.13	53.85 × 33.65	58.37 × 25.01
27 in	54.86 × 41.15	53.55 × 42.84	59.77 × 33.62	58.16 × 36.35	63.03 × 27.01
28 in	56.90 × 42.67	55.54 × 44.43	61.99 × 34.87	60.31 × 37.69	65.37 × 28.02
29 in	58.93 × 44.20	57.52 × 46.02	64.20 × 36.11	62.46 × 39.04	67.70 × 29.02
32 in	65.02 × 48.77	63.47 × 50.78	70.84 × 39.85	68.93 × 43.08	74.71 × 32.02
34 in	69.09 × 51.82	67.44 × 53.95	75.27 × 42.34	73.23 × 45.77	79.38 × 34.02
35 in	71.12 × 53.34	69.42 × 55.54	77.48 × 43.58	75.39 × 47.12	81.71 × 35.02
38 in	77.22 × 57.91	75.37 × 60.30	84.12 × 47.32	81.85 × 51.16	88.72 × 38.02
40 in	81.28 × 60.96	79.34 × 63.47	88.55 × 49.81	86.16 × 53.85	93.39 × 40.02
42 in	85.34 × 64.01	83.30 × 66.64	92.98 × 52.30	90.46 × 56.54	98.05 × 42.02

Notes

• The units for the length and width values listed after the panel are all centimeters (cm).
• The above monitor sizes are mainly based on common computer monitors between 17 and 42 inches on the market.
• The table values are rounded to two decimal places; actual sizes should still be based on each manufacturer’s specification sheet.

How to Calculate Monitor Length and Width Yourself

If you want to verify or calculate other sizes yourself, you can use the following formulas (units: centimeters):

• Diagonal length (cm) = inches × 2.54
• Long side = diagonal × long-side ratio ÷ √(long-side ratio² + short-side ratio²)
• Short side = diagonal × short-side ratio ÷ √(long-side ratio² + short-side ratio²)

Taking a 24-inch 16:9 monitor as an example: the diagonal is 24 × 2.54 = 60.96 cm, the long side = 60.96 × 16 ÷ √(16²+9²) ≈ 53.13 cm, and the short side ≈ 29.89 cm, matching the table above.