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Population in Mongolia compared to Sierra Leone: Trends, Charts, Rankings

Updated on by Georank team

The latest officially reported population of Mongolia was 3,524,788 in 2024 vs 8,642,022 people in Sierra Leone in 2024. In 2026, based on the adjusted UN estimation, the current Mongolia's population is 3,620,317 people compared to 9,049,533 in Sierra Leone.

Population statistics:

  • Sierra Leone's population is 2.5 times bigger than Mongolia's.
  • Mongolia is ranked the 132nd most populous country in the world, while Sierra Leone is the 101st.
  • The countries together account for 0.15% of the world: 0.04% for Mongolia vs 0.11% for Sierra Leone.
  • For the last 10 years, Mongolia has had an average growth rate of +1.79% per year vs +2.32% in Sierra Leone.
  • Since 2006, the population of Mongolia has increased from 2.57M people to 3.62M (41% growth), while Sierra Leone has grown from 5.62M to 9.05M (60.9% growth).

Mongolia vs Sierra Leone: population by year and forecast

Mongolia
Factual

Projection
Sierra Leone
Factual

Projection
1x
Year Population
Mongolia Sierra Leone
2100 5,629,299 16,111,324
2099 5,623,066 16,126,181
2098 5,615,212 16,139,280
2097 5,606,511 16,154,153
2096 5,597,140 16,164,923
2095 5,585,917 16,173,557
2094 5,574,522 16,173,155
2093 5,562,381 16,177,864
2092 5,549,290 16,175,032
2091 5,535,819 16,168,153
2090 5,521,210 16,158,415
2089 5,505,877 16,146,773
2088 5,490,024 16,133,018
2087 5,474,226 16,116,823
2086 5,458,465 16,089,780
2085 5,441,196 16,068,438
2084 5,423,740 16,044,782
2083 5,405,563 16,011,134
2082 5,387,443 15,975,073
2081 5,368,417 15,935,071
2080 5,348,645 15,896,846
2079 5,328,073 15,854,898
2078 5,306,120 15,805,607
2077 5,285,225 15,754,551
2076 5,263,067 15,699,439
2075 5,240,553 15,639,458
2074 5,217,755 15,584,377
2073 5,194,484 15,516,736
2072 5,171,399 15,446,543
2071 5,147,939 15,374,790
2070 5,123,730 15,297,449
2069 5,100,078 15,216,666
2068 5,075,923 15,128,048
2067 5,051,712 15,032,144
2066 5,026,451 14,935,222
2065 5,001,559 14,837,697
2064 4,977,095 14,740,749
2063 4,952,721 14,642,031
2062 4,928,284 14,529,557
2061 4,903,616 14,423,861
2060 4,877,808 14,311,215
2059 4,851,900 14,198,706
2058 4,825,704 14,080,827
2057 4,798,069 13,960,869
2056 4,770,106 13,836,132
2055 4,741,145 13,706,113
2054 4,710,703 13,579,802
2053 4,678,720 13,444,465
2052 4,645,641 13,303,409
2051 4,611,080 13,156,370
2050 4,575,698 13,010,109
2049 4,538,221 12,867,021
2048 4,499,652 12,716,015
2047 4,459,534 12,570,250
2046 4,418,220 12,414,307
2045 4,375,263 12,257,874
2044 4,332,061 12,092,075
2043 4,288,836 11,931,531
2042 4,244,827 11,770,467
2041 4,200,917 11,602,993
2040 4,157,409 11,431,337
2039 4,114,122 11,262,807
2038 4,071,754 11,100,099
2037 4,029,761 10,931,629
2036 3,988,994 10,760,758
2035 3,949,374 10,585,702
2034 3,910,459 10,413,826
2033 3,872,505 10,241,196
2032 3,835,471 10,062,575
2031 3,799,194 9,883,708
2030 3,762,550 9,708,038
2029 3,725,673 9,532,000
2028 3,687,959 9,360,873
2027 3,649,213 9,179,702
2026 3,609,604 9,001,269
2025 3,568,196 8,822,114
2024 3,524,788 8,642,022
2023 3,481,145 8,460,512
2022 3,433,748 8,276,807
2021 3,383,741 8,094,602
2020 3,327,204 7,912,558
2019 3,267,673 7,731,991
2018 3,208,189 7,554,563
2017 3,148,917 7,379,299
2016 3,088,856 7,205,328
2015 3,026,864 7,037,655
2014 2,963,113 6,876,385
2013 2,899,011 6,714,051
2012 2,839,705 6,551,080
2011 2,786,317 6,387,251
2010 2,738,622 6,222,714
2009 2,691,115 6,055,646
2008 2,643,201 5,894,722
2007 2,601,850 5,749,352
2006 2,567,168 5,624,466
2005 2,536,407 5,501,712
2004 2,508,412 5,355,717
2003 2,480,374 5,177,687
2002 2,449,027 4,971,435
2001 2,417,751 4,692,716
2000 2,388,299 4,423,611
1999 2,356,813 4,318,043
1998 2,323,809 4,295,785
1997 2,291,750 4,253,716
1996 2,259,507 4,199,210
1995 2,224,945 4,179,179
1994 2,189,395 4,173,105
1993 2,165,130 4,157,130
1992 2,167,790 4,166,366
1991 2,165,342 4,246,267
1990 2,098,710 4,196,828
1989 2,124,185 4,034,037
1988 2,076,322 3,934,517
1987 2,022,800 3,829,718
1986 1,970,965 3,728,380
1985 1,921,514 3,638,438
1984 1,874,349 3,558,758
1983 1,829,092 3,481,646
1982 1,785,364 3,408,183
1981 1,742,857 3,338,940
1980 1,701,335 3,272,089
1979 1,660,659 3,207,499
1978 1,619,468 3,145,517
1977 1,576,245 3,085,354
1976 1,531,945 3,028,820
1975 1,488,296 2,974,657
1974 1,446,050 2,920,459
1973 1,405,502 2,866,955
1972 1,366,821 2,814,388
1971 1,330,071 2,763,222
1970 1,295,272 2,712,286
1969 1,262,284 2,661,365
1968 1,229,930 2,611,532
1967 1,196,996 2,562,384
1966 1,163,754 2,514,638
1965 1,131,177 2,468,666
1964 1,100,234 2,424,390
1963 1,071,362 2,382,258
1962 1,041,444 2,342,242
1961 1,009,284 2,304,227
1960 977,595 2,268,356

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/mongolia/sierra-leone | CC BY

From 2006 to 2016, the population of Mongolia increased by 521,688 people (a 20.3% growth), while Sierra Leone gained 1,580,862 people (a 28.1% growth).

For the next 10 years, from 2016 to 2026, Mongolia gained 531,461 people (a 17.2% growth), while Sierra Leone's population increased by 1,844,205 people (a 25.6% growth).

Mongolia was ranked 137th most populous country in 2006 and is 132nd in 2026. Sierra Leone was ranked 106th in 2006 and ranked 101st now.

The UN's World Population Prospects forecasts that in 24 years (in 2050) Mongolia's population will grow by 26.4% to 4,575,698 people with a rank change from 132nd to 130th. The population of Sierra Leone will increase by 43.8% to 13,010,109 people and rank change from 101st to 91st.

Mongolia is projected to reach its peak in 2100 at 5.63M people compared to the peak of 16.2M people in 2093 for Sierra Leone.

Population growth rate by year

Mongolia
Factual

Projection
Sierra Leone
Factual

Projection
1x
Year Growth rate
Mongolia Sierra Leone
2100 0.11% -0.09%
2099 0.14% -0.08%
2098 0.16% -0.09%
2097 0.17% -0.07%
2096 0.2% -0.05%
2095 0.2% 0.002%
2094 0.22% -0.03%
2093 0.24% 0.02%
2092 0.24% 0.04%
2091 0.26% 0.06%
2090 0.28% 0.07%
2089 0.29% 0.09%
2088 0.29% 0.1%
2087 0.29% 0.17%
2086 0.32% 0.13%
2085 0.32% 0.15%
2084 0.34% 0.21%
2083 0.34% 0.23%
2082 0.35% 0.25%
2081 0.37% 0.24%
2080 0.39% 0.26%
2079 0.41% 0.31%
2078 0.4% 0.32%
2077 0.42% 0.35%
2076 0.43% 0.38%
2075 0.44% 0.35%
2074 0.45% 0.44%
2073 0.45% 0.45%
2072 0.46% 0.47%
2071 0.47% 0.51%
2070 0.46% 0.53%
2069 0.48% 0.59%
2068 0.48% 0.64%
2067 0.5% 0.65%
2066 0.5% 0.66%
2065 0.49% 0.66%
2064 0.49% 0.67%
2063 0.5% 0.77%
2062 0.5% 0.73%
2061 0.53% 0.79%
2060 0.53% 0.79%
2059 0.54% 0.84%
2058 0.58% 0.86%
2057 0.59% 0.9%
2056 0.61% 0.95%
2055 0.65% 0.93%
2054 0.68% 1.01%
2053 0.71% 1.06%
2052 0.75% 1.12%
2051 0.77% 1.12%
2050 0.83% 1.11%
2049 0.86% 1.19%
2048 0.9% 1.16%
2047 0.94% 1.26%
2046 0.98% 1.28%
2045 1% 1.37%
2044 1.01% 1.35%
2043 1.04% 1.37%
2042 1.05% 1.44%
2041 1.05% 1.5%
2040 1.05% 1.5%
2039 1.04% 1.47%
2038 1.04% 1.54%
2037 1.02% 1.59%
2036 1% 1.65%
2035 1% 1.65%
2034 0.98% 1.69%
2033 0.97% 1.78%
2032 0.95% 1.81%
2031 0.97% 1.81%
2030 0.99% 1.85%
2029 1.02% 1.83%
2028 1.06% 1.97%
2027 1.1% 1.98%
2026 1.16% 2.03%
2025 1.23% 2.08%
2024 1.25% 2.15%
2023 1.38% 2.22%
2022 1.48% 2.25%
2021 1.7% 2.3%
2020 1.82% 2.34%
2019 1.85% 2.35%
2018 1.88% 2.38%
2017 1.94% 2.41%
2016 2.05% 2.38%
2015 2.15% 2.35%
2014 2.21% 2.42%
2013 2.09% 2.49%
2012 1.92% 2.56%
2011 1.74% 2.64%
2010 1.77% 2.76%
2009 1.81% 2.73%
2008 1.59% 2.53%
2007 1.35% 2.22%
2006 1.21% 2.23%
2005 1.12% 2.73%
2004 1.13% 3.44%
2003 1.28% 4.15%
2002 1.29% 5.94%
2001 1.23% 6.08%
2000 1.34% 2.44%
1999 1.42% 0.52%
1998 1.4% 0.99%
1997 1.43% 1.3%
1996 1.55% 0.48%
1995 1.62% 0.15%
1994 1.12% 0.38%
1993 -0.12% -0.22%
1992 0.11% -1.88%
1991 3.17% 1.18%
1990 -1.2% 4.04%
1989 2.31% 2.53%
1988 2.65% 2.74%
1987 2.63% 2.72%
1986 2.57% 2.47%
1985 2.52% 2.24%
1984 2.47% 2.21%
1983 2.45% 2.16%
1982 2.44% 2.07%
1981 2.44% 2.04%
1980 2.45% 2.01%
1979 2.54% 1.97%
1978 2.74% 1.95%
1977 2.89% 1.87%
1976 2.93% 1.82%
1975 2.92% 1.86%
1974 2.88% 1.87%
1973 2.83% 1.87%
1972 2.76% 1.85%
1971 2.69% 1.88%
1970 2.61% 1.91%
1969 2.63% 1.91%
1968 2.75% 1.92%
1967 2.86% 1.9%
1966 2.88% 1.86%
1965 2.81% 1.83%
1964 2.69% 1.77%
1963 2.87% 1.71%
1962 3.19% 1.65%
1961 3.24% 1.58%

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/mongolia/sierra-leone | CC BY

In 2024, the population of Mongolia grew by 1.25%, while Sierra Leone's population grew by 2.15%.

Live population counters

Mongolia Sierra Leone
Current population
3620317
9049533
Population rank 132/197 101/197
Percent of world population 0.04% 0.11%
One net population change
12 minutes
2.9 minutes
One birth every
7.95 minutes
2.03 minutes
One death every
27.5 minutes
7.5 minutes
Daily growth/decline +120 +497
Annual growth/decline +43,643 +181,510
Annual growth/decline rate +1.25% +2.15%
Population growth rate rank 86/197 47/197
One migration net change every
4.63 days
46.6 minutes
Annual migration change +79 -11,309
Net migration rank 74/196 136/196
Foreign-born residents 22,589 49,997
Foreign-born residents rank 169/195 151/195
Foreign-born share of population 0.6% 0.6%
Foreign-born share rank 171/195 174/195

Natural population change vs migration

Mongolia
Natural

Migration
Sierra Leone
Natural

Migration
1x
Year Population change
Mongolia Sierra Leone
Natural Migration Natural Migration
2025 - 79 - -11,309
2024 - 83 - -11,000
2023 46,995 0 188,788 -4,000
2022 47,730 0 186,625 -4,000
2021 52,109 0 183,326 -1,544
2020 60,888 0 181,015 1,292
2019 61,433 8,660 181,068 -2,238
2018 60,635 7,811 178,772 -2,741
2017 57,940 6,831 173,259 1,234
2016 62,086 5,633 168,784 4,657
2015 64,473 4,307 162,275 -356
2014 66,078 2,921 160,137 485
2013 62,618 1,505 161,265 2,773
2012 55,942 351 160,915 988
2011 50,711 -505 158,858 6,895
2010 44,914 -6,444 155,338 7,983
2009 48,876 -15,007 152,669 18,145
2008 45,843 -17,277 149,855 1,182
2007 39,636 -15,220 145,740 -6,042
2006 33,609 -11,934 144,127 -34,052
2005 29,290 -8,924 137,234 -1,805
2004 28,418 -8,148 132,661 23,897
2003 28,827 -7,986 130,312 69,185
2002 30,439 -8,934 126,429 86,578
2001 32,052 -10,244 116,647 227,791
2000 32,753 -11,241 110,754 83,013
1999 32,283 -13,481 102,295 -84,926
1998 31,757 -10,315 103,906 -76,766
1997 32,403 -9,132 105,433 -48,437
1996 33,741 -8,626 104,140 -52,110
1995 34,473 -7,346 100,885 -112,857
1994 34,711 -5,449 101,486 -77,371
1993 36,924 -5,429 103,317 -95,476
1992 42,437 -8,404 103,251 -129,565
1991 47,884 -11,427 105,477 -238,965
1990 49,443 -11,881 100,778 131,587
1989 51,420 -9,757 98,298 -5,079
1988 51,588 2,459 96,344 9,470
1987 51,140 1,855 94,235 9,558
1986 50,329 354 90,902 7,992
1985 49,944 -1,719 88,869 -7,873
1984 48,562 -2,452 87,072 -8,708
1983 46,919 -2,522 84,628 -8,783
1982 45,179 -2,132 82,457 -11,379
1981 43,588 -1,615 80,111 -12,699
1980 42,343 -1,268 77,932 -11,641
1979 41,568 -1,296 75,992 -13,095
1978 40,276 1,833 74,130 -13,073
1977 38,995 5,354 71,663 -12,399
1976 37,670 6,577 69,506 -15,686
1975 36,490 6,556 67,560 -13,058
1974 35,297 6,153 65,357 -11,473
1973 33,993 5,647 62,443 -9,322
1972 32,727 4,999 60,279 -8,267
1971 31,536 4,238 58,484 -8,162
1970 30,558 3,263 56,513 -4,957
1969 29,781 2,366 54,768 -4,485
1968 29,017 3,535 53,126 -3,743
1967 28,178 5,139 51,734 -2,819
1966 27,338 5,837 49,486 -2,911
1965 26,364 5,610 47,223 -1,851
1964 25,317 4,599 45,487 -2,308
1963 24,142 3,687 43,569 -2,480
1962 22,960 9,049 41,603 -2,658
1961 21,873 10,440 40,022 -2,947
1960 20,726 10,334 38,192 -3,528

Data sources: World Bank | Health (1960–2025, retrieved 2026-04-06).

GeoRank.org/population/mongolia/sierra-leone | CC BY

Over the last 10 years, 94.1% of the population change in Mongolia is from natural causes (a gain of 580,367 people) and 5.87% is from migration (a gain of 36,163 people). In Sierra Leone 99.6% is from natural causes (a gain of 1,764,049 people) and 0.41% is from migration (a loss of 7,211 people).

As of 2024, 22,589 residents or 0.6% of the population were not native-born in Mongolia, compared to 49,997 people or 0.6% in Sierra Leone.

Biggest cities by population

Mongolia
City Population
Ulaanbaatar 1.4M
Bulgan 12.3K
Sierra Leone
City Population
Freetown 951K
Bo 234K
Kenema 188K

Compare countries by 7 more topics

Population map with other countries

1x

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/mongolia/sierra-leone | CC BY

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Data sources:

  1. World Bank | Health (1960–2025, retrieved 2026-04-06)
  2. United Nations | World Population Prospects (1960–2100, retrieved 2026-03-10)
  3. U.S. Census Bureau (1960–2025, retrieved 2026-02-08)
  4. Central Intelligence Agency (CIA) (2000–2019, retrieved 2026-02-20)
  5. Wikidata (2026, retrieved 2026-02-08)

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