The latest officially reported population of Iran was 91,567,738 in 2024 vs 40,583,164 people in Yemen in 2024. In 2026, based on the adjusted UN estimation, the current Iran's population is 93,468,444 people compared to 43,325,643 in Yemen.
Population statistics:
- Iran's population is 2.16 times bigger than Yemen's.
- Iran is ranked the 17th most populous country in the world, while Yemen is the 37th.
- The countries together account for 1.65% of the world: 1.13% for Iran vs 0.52% for Yemen.
- For the last 10 years, Iran has had an average growth rate of +1.19% per year vs +3% in Yemen.
- Since 2006, the population of Iran has increased from 73.4M people to 93.5M (27.4% growth), while Yemen has grown from 23.5M to 43.3M (84% growth).
Iran vs Yemen: population by year and forecast
| Year | Population | |
|---|---|---|
Iran
|
Yemen
|
|
| 2100 | 80,713,760 | 111,531,602 |
| 2099 | 81,246,718 | 111,216,538 |
| 2098 | 81,770,953 | 110,873,896 |
| 2097 | 82,295,714 | 110,513,248 |
| 2096 | 82,818,575 | 110,125,357 |
| 2095 | 83,338,446 | 109,718,989 |
| 2094 | 83,854,648 | 109,287,747 |
| 2093 | 84,371,569 | 108,834,256 |
| 2092 | 84,888,626 | 108,350,834 |
| 2091 | 85,410,099 | 107,845,139 |
| 2090 | 85,934,675 | 107,319,234 |
| 2089 | 86,466,409 | 106,769,903 |
| 2088 | 87,004,165 | 106,198,480 |
| 2087 | 87,549,685 | 105,606,248 |
| 2086 | 88,105,571 | 104,994,691 |
| 2085 | 88,668,329 | 104,356,315 |
| 2084 | 89,239,709 | 103,704,067 |
| 2083 | 89,817,194 | 103,033,111 |
| 2082 | 90,402,538 | 102,348,794 |
| 2081 | 90,995,822 | 101,642,012 |
| 2080 | 91,595,122 | 100,920,728 |
| 2079 | 92,196,842 | 100,179,245 |
| 2078 | 92,801,160 | 99,422,962 |
| 2077 | 93,405,954 | 98,654,481 |
| 2076 | 94,007,669 | 97,862,812 |
| 2075 | 94,606,607 | 97,057,105 |
| 2074 | 95,197,577 | 96,230,615 |
| 2073 | 95,783,994 | 95,389,748 |
| 2072 | 96,355,853 | 94,528,518 |
| 2071 | 96,915,335 | 93,646,094 |
| 2070 | 97,460,813 | 92,750,891 |
| 2069 | 97,988,897 | 91,836,719 |
| 2068 | 98,496,927 | 90,906,457 |
| 2067 | 98,978,509 | 89,961,778 |
| 2066 | 99,439,391 | 88,998,844 |
| 2065 | 99,877,457 | 88,022,210 |
| 2064 | 100,288,977 | 87,033,422 |
| 2063 | 100,668,199 | 86,020,867 |
| 2062 | 101,017,348 | 84,985,459 |
| 2061 | 101,332,810 | 83,934,120 |
| 2060 | 101,612,261 | 82,867,105 |
| 2059 | 101,858,931 | 81,781,887 |
| 2058 | 102,061,144 | 80,678,032 |
| 2057 | 102,228,085 | 79,563,835 |
| 2056 | 102,358,266 | 78,436,146 |
| 2055 | 102,449,092 | 77,296,391 |
| 2054 | 102,498,594 | 76,143,587 |
| 2053 | 102,508,245 | 74,985,186 |
| 2052 | 102,480,373 | 73,813,387 |
| 2051 | 102,417,847 | 72,631,340 |
| 2050 | 102,318,917 | 71,436,891 |
| 2049 | 102,189,816 | 70,243,074 |
| 2048 | 102,024,233 | 69,043,876 |
| 2047 | 101,832,213 | 67,843,741 |
| 2046 | 101,613,554 | 66,638,116 |
| 2045 | 101,371,784 | 65,433,874 |
| 2044 | 101,104,998 | 64,230,423 |
| 2043 | 100,818,045 | 63,031,296 |
| 2042 | 100,512,032 | 61,838,177 |
| 2041 | 100,188,214 | 60,651,763 |
| 2040 | 99,849,875 | 59,475,172 |
| 2039 | 99,501,869 | 58,303,694 |
| 2038 | 99,137,385 | 57,135,690 |
| 2037 | 98,759,167 | 55,973,689 |
| 2036 | 98,366,612 | 54,809,098 |
| 2035 | 97,963,082 | 53,641,994 |
| 2034 | 97,546,148 | 52,476,195 |
| 2033 | 97,118,106 | 51,307,469 |
| 2032 | 96,671,440 | 50,140,351 |
| 2031 | 96,204,118 | 48,969,961 |
| 2030 | 95,718,604 | 47,786,079 |
| 2029 | 95,195,996 | 46,594,926 |
| 2028 | 94,623,034 | 45,403,313 |
| 2027 | 93,987,260 | 44,203,683 |
| 2026 | 93,276,075 | 43,000,078 |
| 2025 | 92,478,162 | 41,792,731 |
| 2024 | 91,567,738 | 40,583,164 |
| 2023 | 90,608,707 | 39,390,799 |
| 2022 | 89,524,246 | 38,222,876 |
| 2021 | 88,455,488 | 37,140,230 |
| 2020 | 87,723,443 | 36,134,863 |
| 2019 | 87,051,648 | 35,111,408 |
| 2018 | 86,117,998 | 34,085,182 |
| 2017 | 85,026,754 | 33,090,921 |
| 2016 | 83,812,228 | 32,109,010 |
| 2015 | 82,619,362 | 31,159,379 |
| 2014 | 81,502,045 | 30,226,309 |
| 2013 | 80,414,686 | 29,312,952 |
| 2012 | 79,370,580 | 28,433,647 |
| 2011 | 78,383,598 | 27,582,897 |
| 2010 | 77,420,842 | 26,754,387 |
| 2009 | 76,457,825 | 25,927,724 |
| 2008 | 75,514,204 | 25,111,941 |
| 2007 | 74,602,648 | 24,318,082 |
| 2006 | 73,392,747 | 23,543,083 |
| 2005 | 71,828,455 | 22,790,085 |
| 2004 | 70,256,316 | 22,095,167 |
| 2003 | 68,769,340 | 21,456,379 |
| 2002 | 68,011,317 | 20,835,086 |
| 2001 | 67,452,005 | 20,226,147 |
| 2000 | 66,418,659 | 19,624,141 |
| 1999 | 65,445,391 | 19,029,420 |
| 1998 | 64,519,859 | 18,446,013 |
| 1997 | 63,639,638 | 17,873,936 |
| 1996 | 62,881,300 | 17,313,177 |
| 1995 | 62,205,567 | 16,740,058 |
| 1994 | 61,520,598 | 16,149,147 |
| 1993 | 61,403,543 | 15,563,914 |
| 1992 | 61,184,983 | 14,989,494 |
| 1991 | 59,986,931 | 14,430,201 |
| 1990 | 58,380,092 | 13,887,862 |
| 1989 | 56,704,914 | 13,364,174 |
| 1988 | 55,072,694 | 12,859,708 |
| 1987 | 53,323,493 | 12,369,912 |
| 1986 | 51,446,045 | 11,901,040 |
| 1985 | 49,582,289 | 11,453,825 |
| 1984 | 47,793,998 | 11,025,597 |
| 1983 | 46,029,535 | 10,621,499 |
| 1982 | 44,272,141 | 10,241,006 |
| 1981 | 41,989,312 | 9,882,362 |
| 1980 | 39,842,324 | 9,543,358 |
| 1979 | 38,424,952 | 9,224,194 |
| 1978 | 37,126,535 | 8,926,586 |
| 1977 | 35,933,181 | 8,648,222 |
| 1976 | 34,837,271 | 8,384,113 |
| 1975 | 33,802,973 | 8,133,598 |
| 1974 | 32,796,463 | 7,896,783 |
| 1973 | 31,839,838 | 7,672,796 |
| 1972 | 30,921,179 | 7,460,068 |
| 1971 | 30,029,071 | 7,257,462 |
| 1970 | 29,145,100 | 7,065,279 |
| 1969 | 28,273,482 | 6,875,859 |
| 1968 | 27,437,391 | 6,690,524 |
| 1967 | 26,628,432 | 6,516,444 |
| 1966 | 25,829,270 | 6,351,494 |
| 1965 | 25,036,978 | 6,195,593 |
| 1964 | 24,262,859 | 6,048,006 |
| 1963 | 23,519,005 | 5,911,135 |
| 1962 | 22,807,907 | 5,782,221 |
| 1961 | 22,125,726 | 5,655,232 |
| 1960 | 21,470,434 | 5,532,301 |
Data sources: United Nations | World Population Prospects (2025–2100, retrieved 2026-03-10); World Bank | Health (1960–2024, retrieved 2026-04-06).
GeoRank.org/population/iran/yemen | CC BY 
From 2006 to 2016, the population of Iran increased by 10,419,481 people (a 14.2% growth), while Yemen gained 8,565,927 people (a 36.4% growth).
For the next 10 years, from 2016 to 2026, Iran gained 9,656,216 people (a 11.5% growth), while Yemen's population increased by 11,216,633 people (a 34.9% growth).
Iran was ranked 17th most populous country in 2006 and is still 17th in 2026. Yemen was ranked 47th in 2006 and ranked 37th now.
The UN's World Population Prospects forecasts that in 24 years (in 2050) Iran's population will grow by 9.47% to 102,318,917 people with a rank change from 17th to 18th. The population of Yemen will increase by 64.9% to 71,436,891 people and rank change from 37th to 29th.
Iran is projected to reach its peak in 2053 at 103M people compared to the peak of 112M people in 2100 for Yemen.
Population growth rate by year
| Year | Growth rate | |
|---|---|---|
|
Iran
|
Yemen
|
|
| 2100 | -0.66% | 0.28% |
| 2099 | -0.64% | 0.31% |
| 2098 | -0.64% | 0.33% |
| 2097 | -0.63% | 0.35% |
| 2096 | -0.62% | 0.37% |
| 2095 | -0.62% | 0.39% |
| 2094 | -0.61% | 0.42% |
| 2093 | -0.61% | 0.45% |
| 2092 | -0.61% | 0.47% |
| 2091 | -0.61% | 0.49% |
| 2090 | -0.61% | 0.51% |
| 2089 | -0.62% | 0.54% |
| 2088 | -0.62% | 0.56% |
| 2087 | -0.63% | 0.58% |
| 2086 | -0.63% | 0.61% |
| 2085 | -0.64% | 0.63% |
| 2084 | -0.64% | 0.65% |
| 2083 | -0.65% | 0.67% |
| 2082 | -0.65% | 0.7% |
| 2081 | -0.65% | 0.71% |
| 2080 | -0.65% | 0.74% |
| 2079 | -0.65% | 0.76% |
| 2078 | -0.65% | 0.78% |
| 2077 | -0.64% | 0.81% |
| 2076 | -0.63% | 0.83% |
| 2075 | -0.62% | 0.86% |
| 2074 | -0.61% | 0.88% |
| 2073 | -0.59% | 0.91% |
| 2072 | -0.58% | 0.94% |
| 2071 | -0.56% | 0.97% |
| 2070 | -0.54% | 1% |
| 2069 | -0.52% | 1.02% |
| 2068 | -0.49% | 1.05% |
| 2067 | -0.46% | 1.08% |
| 2066 | -0.44% | 1.11% |
| 2065 | -0.41% | 1.14% |
| 2064 | -0.38% | 1.18% |
| 2063 | -0.35% | 1.22% |
| 2062 | -0.31% | 1.25% |
| 2061 | -0.28% | 1.29% |
| 2060 | -0.24% | 1.33% |
| 2059 | -0.2% | 1.37% |
| 2058 | -0.16% | 1.4% |
| 2057 | -0.13% | 1.44% |
| 2056 | -0.09% | 1.47% |
| 2055 | -0.05% | 1.51% |
| 2054 | -0.009% | 1.54% |
| 2053 | 0.03% | 1.59% |
| 2052 | 0.06% | 1.63% |
| 2051 | 0.1% | 1.67% |
| 2050 | 0.13% | 1.7% |
| 2049 | 0.16% | 1.74% |
| 2048 | 0.19% | 1.77% |
| 2047 | 0.22% | 1.81% |
| 2046 | 0.24% | 1.84% |
| 2045 | 0.26% | 1.87% |
| 2044 | 0.28% | 1.9% |
| 2043 | 0.3% | 1.93% |
| 2042 | 0.32% | 1.96% |
| 2041 | 0.34% | 1.98% |
| 2040 | 0.35% | 2.01% |
| 2039 | 0.37% | 2.04% |
| 2038 | 0.38% | 2.08% |
| 2037 | 0.4% | 2.12% |
| 2036 | 0.41% | 2.18% |
| 2035 | 0.43% | 2.22% |
| 2034 | 0.44% | 2.28% |
| 2033 | 0.46% | 2.33% |
| 2032 | 0.49% | 2.39% |
| 2031 | 0.51% | 2.48% |
| 2030 | 0.55% | 2.56% |
| 2029 | 0.61% | 2.62% |
| 2028 | 0.68% | 2.71% |
| 2027 | 0.76% | 2.8% |
| 2026 | 0.86% | 2.89% |
| 2025 | 0.99% | 2.98% |
| 2024 | 1.06% | 3.03% |
| 2023 | 1.21% | 3.06% |
| 2022 | 1.21% | 2.92% |
| 2021 | 0.83% | 2.78% |
| 2020 | 0.77% | 2.91% |
| 2019 | 1.08% | 3.01% |
| 2018 | 1.28% | 3% |
| 2017 | 1.45% | 3.06% |
| 2016 | 1.44% | 3.05% |
| 2015 | 1.37% | 3.09% |
| 2014 | 1.35% | 3.12% |
| 2013 | 1.32% | 3.09% |
| 2012 | 1.26% | 3.08% |
| 2011 | 1.24% | 3.1% |
| 2010 | 1.26% | 3.19% |
| 2009 | 1.25% | 3.25% |
| 2008 | 1.22% | 3.26% |
| 2007 | 1.65% | 3.29% |
| 2006 | 2.18% | 3.3% |
| 2005 | 2.24% | 3.15% |
| 2004 | 2.16% | 2.98% |
| 2003 | 1.11% | 2.98% |
| 2002 | 0.83% | 3.01% |
| 2001 | 1.56% | 3.07% |
| 2000 | 1.49% | 3.13% |
| 1999 | 1.43% | 3.16% |
| 1998 | 1.38% | 3.2% |
| 1997 | 1.21% | 3.24% |
| 1996 | 1.09% | 3.42% |
| 1995 | 1.11% | 3.66% |
| 1994 | 0.19% | 3.76% |
| 1993 | 0.36% | 3.83% |
| 1992 | 2% | 3.88% |
| 1991 | 2.75% | 3.91% |
| 1990 | 2.95% | 3.92% |
| 1989 | 2.96% | 3.92% |
| 1988 | 3.28% | 3.96% |
| 1987 | 3.65% | 3.94% |
| 1986 | 3.76% | 3.9% |
| 1985 | 3.74% | 3.88% |
| 1984 | 3.83% | 3.8% |
| 1983 | 3.97% | 3.72% |
| 1982 | 5.44% | 3.63% |
| 1981 | 5.39% | 3.55% |
| 1980 | 3.69% | 3.46% |
| 1979 | 3.5% | 3.33% |
| 1978 | 3.32% | 3.22% |
| 1977 | 3.15% | 3.15% |
| 1976 | 3.06% | 3.08% |
| 1975 | 3.07% | 3% |
| 1974 | 3% | 2.92% |
| 1973 | 2.97% | 2.85% |
| 1972 | 2.97% | 2.79% |
| 1971 | 3.03% | 2.72% |
| 1970 | 3.08% | 2.75% |
| 1969 | 3.05% | 2.77% |
| 1968 | 3.04% | 2.67% |
| 1967 | 3.09% | 2.6% |
| 1966 | 3.16% | 2.52% |
| 1965 | 3.19% | 2.44% |
| 1964 | 3.16% | 2.32% |
| 1963 | 3.12% | 2.23% |
| 1962 | 3.08% | 2.25% |
| 1961 | 3.05% | 2.22% |
Data sources: United Nations | World Population Prospects (2025–2100, retrieved 2026-03-10); World Bank | Health (1961–2024, retrieved 2026-04-06).
GeoRank.org/population/iran/yemen | CC BY
In 2024, the population of Iran grew by 1.06%, while Yemen's population grew by 3.03%.
Live population counters
|
Iran
|
Yemen
|
|
|---|---|---|
| Current population |
93468444
|
43325643
|
| Population rank | 17/197 | 37/197 |
| Percent of world population | 1.13% | 0.52% |
| One net population change |
32.9 seconds
|
26.4 seconds
|
| One birth every |
26.9 seconds
|
22.7 seconds
|
| One death every |
1.24 minutes
|
2.78 minutes
|
| Daily growth/decline | +2,627 | +3,267 |
| Annual growth/decline | +959,031 | +1,192,365 |
| Annual growth/decline rate | +1.06% | +3.03% |
| Population growth rate rank | 98/197 | 13/197 |
| One migration net change every |
4.51 minutes
|
32.4 minutes
|
| Annual migration change | +116,786 | -16,291 |
| Net migration rank | 14/196 | 148/196 |
| Foreign-born residents | 3,840,654 | 392,997 |
| Foreign-born residents rank | 17/195 | 89/195 |
| Foreign-born share of population | 4.2% | 1% |
| Foreign-born share rank | 103/195 | 156/195 |
Natural population change vs migration
| Year | Population change | |||
|---|---|---|---|---|
|
Iran
|
Yemen
|
|||
| Natural | Migration | Natural | Migration | |
| 2025 | - | 116,786 | - | -16,291 |
| 2024 | - | 190,156 | - | -10,482 |
| 2023 | 750,150 | 262,044 | 1,198,150 | -5,233 |
| 2022 | 753,525 | 403,190 | 1,153,375 | -10,448 |
| 2021 | 645,725 | 334,967 | 1,103,622 | -81,248 |
| 2020 | 663,978 | -180,680 | 1,086,322 | -97,982 |
| 2019 | 893,063 | -32,794 | 1,056,432 | 2,129 |
| 2018 | 1,035,052 | -27,946 | 1,020,238 | -26,335 |
| 2017 | 1,140,549 | 34,849 | 1,006,725 | -12,086 |
| 2016 | 1,186,949 | 66,630 | 975,697 | -6,492 |
| 2015 | 1,178,317 | -46,239 | 939,922 | -9,883 |
| 2014 | 1,158,552 | -56,042 | 920,330 | 15,764 |
| 2013 | 1,119,533 | -47,322 | 884,929 | 5,697 |
| 2012 | 1,073,804 | -57,823 | 845,645 | 22,349 |
| 2011 | 1,023,925 | -65,924 | 806,359 | 27,184 |
| 2010 | 980,380 | -12,849 | 803,246 | 20,269 |
| 2009 | 958,322 | 211 | 798,911 | 30,919 |
| 2008 | 940,983 | -12,184 | 779,123 | 22,621 |
| 2007 | 919,254 | -24,950 | 764,780 | 21,210 |
| 2006 | 884,529 | 640,932 | 750,082 | 13,940 |
| 2005 | 837,305 | 765,873 | 726,708 | 15,283 |
| 2004 | 801,203 | 739,996 | 710,493 | -62,641 |
| 2003 | 732,600 | 700,222 | 694,457 | -64,737 |
| 2002 | 752,205 | -668,962 | 672,494 | -59,648 |
| 2001 | 743,658 | 291,692 | 658,704 | -53,698 |
| 2000 | 731,203 | 300,133 | 646,694 | -47,713 |
| 1999 | 723,237 | 191,988 | 633,166 | -42,731 |
| 1998 | 717,655 | 218,171 | 615,488 | -39,096 |
| 1997 | 726,574 | 98,009 | 604,443 | -36,694 |
| 1996 | 784,508 | -92,435 | 588,786 | -35,043 |
| 1995 | 879,648 | -220,258 | 607,966 | -15,485 |
| 1994 | 1,008,076 | -297,487 | 602,363 | -13,040 |
| 1993 | 1,219,658 | -1,696,091 | 595,459 | -14,332 |
| 1992 | 1,365,466 | -451,945 | 582,072 | -14,372 |
| 1991 | 1,495,594 | -13,059 | 565,837 | -14,964 |
| 1990 | 1,530,434 | 200,711 | 549,654 | -15,847 |
| 1989 | 1,609,739 | 9,460 | 530,464 | -16,876 |
| 1988 | 1,614,512 | 30,688 | 513,296 | -17,952 |
| 1987 | 1,639,644 | 213,524 | 493,337 | -9,097 |
| 1986 | 1,659,289 | 242,411 | 464,665 | -11,151 |
| 1985 | 1,661,750 | 163,999 | 455,576 | -14,660 |
| 1984 | 1,653,051 | 97,748 | 434,674 | -19,143 |
| 1983 | 1,573,612 | 204,544 | 414,823 | -22,152 |
| 1982 | 1,514,240 | 222,390 | 392,302 | -23,981 |
| 1981 | 1,376,830 | 1,452,169 | 374,482 | -25,499 |
| 1980 | 1,361,293 | 103,674 | 355,767 | -26,740 |
| 1979 | 1,294,306 | 75,451 | 336,378 | -27,090 |
| 1978 | 1,156,974 | 70,088 | 312,439 | -26,524 |
| 1977 | 1,091,542 | 68,093 | 296,115 | -25,305 |
| 1976 | 1,013,347 | 18,825 | 281,078 | -23,669 |
| 1975 | 929,481 | 106,921 | 266,815 | -23,192 |
| 1974 | 873,369 | 103,252 | 252,737 | -22,726 |
| 1973 | 831,880 | 104,779 | 240,235 | -22,282 |
| 1972 | 804,043 | 96,614 | 229,322 | -21,826 |
| 1971 | 805,830 | 77,717 | 219,095 | -21,386 |
| 1970 | 794,612 | 89,757 | 207,613 | -20,966 |
| 1969 | 780,660 | 78,196 | 196,305 | -4,121 |
| 1968 | 743,992 | 69,342 | 182,518 | -4,031 |
| 1967 | 727,276 | 77,313 | 173,637 | -3,959 |
| 1966 | 695,040 | 98,709 | 164,091 | -3,874 |
| 1965 | 663,029 | 127,808 | 155,398 | -3,797 |
| 1964 | 635,589 | 121,817 | 147,299 | -3,712 |
| 1963 | 620,126 | 110,190 | 133,781 | -3,640 |
| 1962 | 595,538 | 96,332 | 131,262 | -3,572 |
| 1961 | 594,674 | 77,811 | 129,787 | -3,503 |
| 1960 | 584,060 | 54,041 | 122,994 | -3,431 |
Data sources: World Bank | Health (1960–2025, retrieved 2026-04-06).
GeoRank.org/population/iran/yemen | CC BY
Over the last 10 years, 92.5% of the population change in Iran is from natural causes (a gain of 9,405,860 people) and 7.46% is from migration (a gain of 757,979 people). In Yemen 97.8% is from natural causes (a gain of 10,460,813 people) and 2.17% is from migration (a loss of 231,814 people).
As of 2024, 3,840,654 residents or 4.2% of the population were not native-born in Iran, compared to 392,997 people or 1% in Yemen.
Biggest cities by population
Compare countries by 7 more topics
Population differences between Iran and Yemen
|
Iran
|
Yemen
|
|
|---|---|---|
| Life expectancy | 78.2 years | 69.7 years |
| Average age | 34.3 years | 23.1 years |
| Median age | 34.3 years | 19.3 years |
| Male:Female ratio | 50.8:49.2 | 50.7:49.3 |
| Fertility rate | 1.7 births per woman | 4.59 births per woman |
| Population density | 148.9 ppl/mi² | 210.9 ppl/mi² |
Population map with other countries
Data sources: World Bank | Health (1960–2024, retrieved 2026-04-06); United Nations | World Population Prospects (1960–2026, retrieved 2026-03-10); U.S. Census Bureau (1960–2025, retrieved 2026-02-08); Central Intelligence Agency (CIA) (2000–2019, retrieved 2026-02-20).
GeoRank.org/population/iran/yemen | CC BY
Help us show the world through your eyes
Share a photo of your city and help others discover what it looks like to live there. Your contribution makes our data come alive.
Data sources:
- World Bank | Health (1960–2025, retrieved 2026-04-06)
- United Nations | World Population Prospects (1960–2100, retrieved 2026-03-10)
- U.S. Census Bureau (1960–2025, retrieved 2026-02-08)
- Wikidata (2026, retrieved 2026-02-08)
- Central Intelligence Agency (CIA) (2000–2019, retrieved 2026-02-20)
Creative Commons Attribution (CC BY) — you’re free to copy, share, remix, adapt, and use even commercially as long as you give appropriate credit and clearly indicate if you made changes. Other sources may be subject to different license terms.