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Acres to Square Miles Converter

Type a value in acres to get square miles instantly, or type in the square miles box to convert back. The formula with your number, related units and full tables are below.

AcresFrom

Square milesTo

sq mi

Decimal places

Step-by-step calculation

How to use the Acres to Square Miles Converter

Type a value in the Acres box. The square miles result appears instantly.
Going the other way? Type in the Square miles box, or press the ⇄ swap button.
Set the precision with the decimal places menu.
Check the working in the step-by-step box, then press Copy result or click any row in the tables below.

Acres to square miles formula

sq mi = ac ÷ 640

Take the value in acres.
Divide it by 640 (the number of acres in one square mile).

Example: 640 ac ÷ 640 = 1 sq mi.

Reverse formula (square miles to acres): ac = sq mi × 640. Example: 0.003125 sq mi × 640 = 2 ac.

The factor is a whole number (640), so this one is easy to do in your head or with long division.

ac to sq mi conversion table (1–100)

Click any row to load it into the converter.

Acres to square miles

Acres	Square miles
1 ac	0.00156 sq mi
2 ac	0.00313 sq mi
3 ac	0.00469 sq mi
4 ac	0.00625 sq mi
5 ac	0.00781 sq mi
6 ac	0.00937 sq mi
7 ac	0.01094 sq mi
8 ac	0.0125 sq mi
9 ac	0.01406 sq mi
10 ac	0.01562 sq mi
11 ac	0.01719 sq mi
12 ac	0.01875 sq mi
13 ac	0.02031 sq mi
14 ac	0.02187 sq mi
15 ac	0.02344 sq mi
16 ac	0.025 sq mi
17 ac	0.02656 sq mi
18 ac	0.02813 sq mi
19 ac	0.02969 sq mi
20 ac	0.03125 sq mi
21 ac	0.03281 sq mi
22 ac	0.03438 sq mi
23 ac	0.03594 sq mi
24 ac	0.0375 sq mi
25 ac	0.03906 sq mi
26 ac	0.04063 sq mi
27 ac	0.04219 sq mi
28 ac	0.04375 sq mi
29 ac	0.04531 sq mi
30 ac	0.04688 sq mi
31 ac	0.04844 sq mi
32 ac	0.05 sq mi
33 ac	0.05156 sq mi
34 ac	0.05312 sq mi
35 ac	0.05469 sq mi
36 ac	0.05625 sq mi
37 ac	0.05781 sq mi
38 ac	0.05937 sq mi
39 ac	0.06094 sq mi
40 ac	0.0625 sq mi
41 ac	0.06406 sq mi
42 ac	0.06563 sq mi
43 ac	0.06719 sq mi
44 ac	0.06875 sq mi
45 ac	0.07031 sq mi
46 ac	0.07187 sq mi
47 ac	0.07344 sq mi
48 ac	0.075 sq mi
49 ac	0.07656 sq mi
50 ac	0.07812 sq mi
51 ac	0.07969 sq mi
52 ac	0.08125 sq mi
53 ac	0.08281 sq mi
54 ac	0.08438 sq mi
55 ac	0.08594 sq mi
56 ac	0.0875 sq mi
57 ac	0.08906 sq mi
58 ac	0.09062 sq mi
59 ac	0.09219 sq mi
60 ac	0.09375 sq mi
61 ac	0.09531 sq mi
62 ac	0.09688 sq mi
63 ac	0.09844 sq mi
64 ac	0.1 sq mi
65 ac	0.10156 sq mi
66 ac	0.10312 sq mi
67 ac	0.10469 sq mi
68 ac	0.10625 sq mi
69 ac	0.10781 sq mi
70 ac	0.10938 sq mi
71 ac	0.11094 sq mi
72 ac	0.1125 sq mi
73 ac	0.11406 sq mi
74 ac	0.11563 sq mi
75 ac	0.11719 sq mi
76 ac	0.11875 sq mi
77 ac	0.12031 sq mi
78 ac	0.12187 sq mi
79 ac	0.12344 sq mi
80 ac	0.125 sq mi
81 ac	0.12656 sq mi
82 ac	0.12812 sq mi
83 ac	0.12969 sq mi
84 ac	0.13125 sq mi
85 ac	0.13281 sq mi
86 ac	0.13437 sq mi
87 ac	0.13594 sq mi
88 ac	0.1375 sq mi
89 ac	0.13906 sq mi
90 ac	0.14062 sq mi
91 ac	0.14219 sq mi
92 ac	0.14375 sq mi
93 ac	0.14531 sq mi
94 ac	0.14688 sq mi
95 ac	0.14844 sq mi
96 ac	0.15 sq mi
97 ac	0.15156 sq mi
98 ac	0.15313 sq mi
99 ac	0.15469 sq mi
100 ac	0.15625 sq mi

Square miles to acres

Square miles	Acres
1 sq mi	640 ac
2 sq mi	1,280 ac
3 sq mi	1,920 ac
4 sq mi	2,560 ac
5 sq mi	3,200 ac
6 sq mi	3,840 ac
7 sq mi	4,480 ac
8 sq mi	5,120 ac
9 sq mi	5,760 ac
10 sq mi	6,400 ac
11 sq mi	7,040 ac
12 sq mi	7,680 ac
13 sq mi	8,320 ac
14 sq mi	8,960 ac
15 sq mi	9,600 ac
16 sq mi	10,240 ac
17 sq mi	10,880 ac
18 sq mi	11,520 ac
19 sq mi	12,160 ac
20 sq mi	12,800 ac
21 sq mi	13,440 ac
22 sq mi	14,080 ac
23 sq mi	14,720 ac
24 sq mi	15,360 ac
25 sq mi	16,000 ac
26 sq mi	16,640 ac
27 sq mi	17,280 ac
28 sq mi	17,920 ac
29 sq mi	18,560 ac
30 sq mi	19,200 ac
31 sq mi	19,840 ac
32 sq mi	20,480 ac
33 sq mi	21,120 ac
34 sq mi	21,760 ac
35 sq mi	22,400 ac
36 sq mi	23,040 ac
37 sq mi	23,680 ac
38 sq mi	24,320 ac
39 sq mi	24,960 ac
40 sq mi	25,600 ac
41 sq mi	26,240 ac
42 sq mi	26,880 ac
43 sq mi	27,520 ac
44 sq mi	28,160 ac
45 sq mi	28,800 ac
46 sq mi	29,440 ac
47 sq mi	30,080 ac
48 sq mi	30,720 ac
49 sq mi	31,360 ac
50 sq mi	32,000 ac
51 sq mi	32,640 ac
52 sq mi	33,280 ac
53 sq mi	33,920 ac
54 sq mi	34,560 ac
55 sq mi	35,200 ac
56 sq mi	35,840 ac
57 sq mi	36,480 ac
58 sq mi	37,120 ac
59 sq mi	37,760 ac
60 sq mi	38,400 ac
61 sq mi	39,040 ac
62 sq mi	39,680 ac
63 sq mi	40,320 ac
64 sq mi	40,960 ac
65 sq mi	41,600 ac
66 sq mi	42,240 ac
67 sq mi	42,880 ac
68 sq mi	43,520 ac
69 sq mi	44,160 ac
70 sq mi	44,800 ac
71 sq mi	45,440 ac
72 sq mi	46,080 ac
73 sq mi	46,720 ac
74 sq mi	47,360 ac
75 sq mi	48,000 ac
76 sq mi	48,640 ac
77 sq mi	49,280 ac
78 sq mi	49,920 ac
79 sq mi	50,560 ac
80 sq mi	51,200 ac
81 sq mi	51,840 ac
82 sq mi	52,480 ac
83 sq mi	53,120 ac
84 sq mi	53,760 ac
85 sq mi	54,400 ac
86 sq mi	55,040 ac
87 sq mi	55,680 ac
88 sq mi	56,320 ac
89 sq mi	56,960 ac
90 sq mi	57,600 ac
91 sq mi	58,240 ac
92 sq mi	58,880 ac
93 sq mi	59,520 ac
94 sq mi	60,160 ac
95 sq mi	60,800 ac
96 sq mi	61,440 ac
97 sq mi	62,080 ac
98 sq mi	62,720 ac
99 sq mi	63,360 ac
100 sq mi	64,000 ac

Common values

Acres	Square miles	Example
0.1 ac	0.000156 sq mi	Tenth of an acre
0.25 ac	0.000391 sq mi	Quarter acre lot
0.5 ac	0.000781 sq mi	Half acre
1 ac	0.00156 sq mi	1 acre
1.32 ac	0.00206 sq mi	US football field incl. end zones
2 ac	0.00313 sq mi	2 acres
5 ac	0.01 sq mi	5 acres
10 ac	0.02 sq mi	10 acres
40 ac	0.06 sq mi	Quarter-quarter section
160 ac	0.25 sq mi	Quarter section
640 ac	1 sq mi	1 square mile

About acres and square miles

Acres (ac). The acre is a land area unit equal to 43,560 square feet (about 4,046.86 m²). Historically it was the area a team of oxen could plough in a day.

Square miles (sq mi). A square mile is the area of a square one mile on each side: 640 acres or about 2.59 km².

Frequently asked questions

How many square miles are in an acre?

One acre equals 0.0015625 square miles. Looking at it the other way, one square mile is 640 acres.

How do you convert acres to square miles?

Divide the number of acres by 640. For example, 640 ac ÷ 640 = 1 sq mi.

What is 2 acres in square miles?

2 ac is 0.003125 sq mi.

How do I convert square miles back to acres?

Multiply by 640, or press the ⇄ swap button above. For example, 0.003125 sq mi × 640 = 2 ac.

How big is an acre compared with a hectare?

One acre is 43,560 square feet (4,046.86 m²), while one hectare is 10,000 m². A hectare is about 2.47 acres, and an acre is about 0.405 hectares.

Why is the square-mile factor not 1.609?

Because area squares the length factor: 1 mile = 1.609 km, so 1 square mile = 1.609² = 2.59 km².

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