World Population Clock: 7.4 Billion People (2016) (2024)

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World Population sections

World Population: Past, Present, and Future

At the dawn of agriculture, about 8000 B.C., the population of the world was approximately 5 million. Over the 8,000-year period up to 1 A.D. it grew to 200 million (some estimate 300 million or even 600, suggesting how imprecise population estimates of early historical periods can be), with a growth rate of under 0.05% per year.

A tremendous change occurred with the industrial revolution: whereas it had taken all of human history until around 1800 for world population to reach one billion, the second billion was achieved in only 130 years (1930), the third billion in less than 30 years (1959), the fourth billion in 15 years (1974), and the fifth billion in only 13 years (1987).

During the 20th century alone, the population in the world has grown from 1.65 billion to 6 billion.
In 1970, there were roughly half as many people in the world as there are now.
Because of declining growth rates, it will now take over 200 years to double again.

Sources:

Historical Estimates of World Population - US Census Bureau
The World at Six Billion, World Population, Year 0 to near stabilization [Pdf file] - United Nations Population Division

The chart above illustrates how world population has changed in history.

During the 20th century alone, the population in the world has grown from 1.65 billion to 6 billion.
In 1970, there were roughly half as many people in the world as there are now.
Because of declining growth rates, it will now take over 200 years to double again.

Sources:

Historical Estimates of World Population - US Census Bureau
The World at Six Billion, World Population, Year 0 to near stabilization [Pdf file] - United Nations Population Division

World Population Milestones

8 Billion (2024)

According to the most recent United Nations estimates, the human population of the world is expected to reach 8 billion people in the spring of 2024.

7 Billion (2011)

According to the United Nations, world population reached 7 Billion on October 31, 2011.
The US Census Bureau made a lower estimate, for which the 7 billion mark was only reached on March 12, 2012.

6 Billion (1999)

According to the United Nations, the 6 billion figure was reached on October 12, 1999 (celebrated as the Day of 6 Billion). According to the U.S. Census Bureau instead, the six billion milestone was reached on July 22, 1999, at about 3:49 AM GMT. Yet, according to the U.S. Census web site, the date and time of when 6 billion was reached will probably change because the already uncertain estimates are constantly being updated.

Previous Milestones

5 Billion: 1987
4 Billion: 1974
3 Billion: 1960
2 Billion: 1927
1 Billion: 1804

Summary Table

	1 - 1804 (1803 years): 0.2 to 1 bil.					1804 - 2011 (207 years): from 1 billion to 7 billion
Year	1	1000	1500	1650	1750	1804	1850	1900	1927	1950	1960	1974	1980	1987	1999	2011	2020	2024	2030	2038	2050	2056	2100
Pop, (billions)	0.2	0.275	0.45	0.5	0.7	1	1.2	1.6	2	2.55	3	4	4.5	5	6	7	7.7	8	8.4	9	9.5	10	11.2

Wonder how big was the world's population when you were born?
Check out this simple wizard or this more elaborated one to find out.

Growth Rate

Population in the world is currently (as of 2015-2016) growing at a rate of around 1.13% per year. The average population change is currently estimated at around 80 million per year.

Annual growth rate reached its peak in the late 1960s, when it was at 2% and above. The rate of increase has therefore almost halved since its peak of 2.19 percent, which was reached in 1963.

The annual growth rate is currently declining and is projected to continue to decline in the coming years. Currently, it is estimated that it will become less than 1% by 2020 and less than 0.5% by 2050.

This means that world population will continue to grow in the 21st century, but at a slower rate compared to the recent past. World population has doubled (100% increase) in 40 years from 1959 (3 billion) to 1999 (6 billion). It is now estimated that it will take a further 39 years to increase by another 50%, to become 9 billion by 2038.

The latest United Nations projections indicate that world population will reach 10 billion persons in the year 2056 (six years earlier than previously estimated).

Top 20 Countries 2013-2100

In the year 2022, India's population is expected to surpass China's, to become the largest country in the world.

Nigeria's population is expected to surpass the U.S. population in 2049 to become the third-most populous country in the world after China (in 2100, Nigeria's population is projected at 750 million, while China will be stable at over 1 billion).

World Population by Region

World Population Density (people/km²)

Population density map of the world showing not only countries but also many subdivisions (regions, states, provinces).

Courtesy of Junuxx at en.wikipedia [CC-BY-SA-3.0 or GFDL], via Wikimedia Commons

World Population by Religion

According to a recent study (based on the 2010 world population of 6.9 billion) by The Pew Forum, there are:

2,173,180,000 Christians (31% of world population), of which 50% are Catholic, 37% Protestant, 12% Orthodox, and 1% other.
1,598,510,000 Muslims (23%), of which 87-90% are Sunnis, 10-13% Shia.
1,126,500,000 No Religion affiliation (16%): atheists, agnostics and people whodo not identify with any particular religion. One-in-five people (20%) in the United States are religiously unaffiliated.
1,033,080,000 Hindus (15%), the overwhelming majority (94%) of which live in India.
487,540,000 Buddhists (7%), of which half live in China.
405,120,000 Folk Religionists (6%): faiths that are closely associated with a particulargroup of people, ethnicity or tribe.
58,110,000 Other Religions (1%): Baha’i faith, Taoism,Jainism, Shintoism, Sikhism, Tenrikyo, Wicca, Zoroastrianism and many others.
13,850,000 Jews (0.2%), four-fifths of which live in two countries: United States (41%) and Israel (41%).

World Population by Country

view full table (includes median age, population over 60, fertility rate, and urban population).

Rank	Country	Population (2014)	Share of World Pop	1 Year Change	Area (Km²)	Density (P/Km²)
1	China	1,393,783,836	19.24%	0.59%	9,596,947	145
2	India	1,267,401,849	17.50%	1.22%	3,287,265	386
3	U.S.A.	322,583,006	4.45%	0.79%	9,629,056	34
4	Indonesia	252,812,245	3.49%	1.18%	1,904,567	133
5	Brazil	202,033,670	2.79%	0.83%	8,514,209	24
6	Pakistan	185,132,926	2.56%	1.64%	796,096	233
7	Nigeria	178,516,904	2.46%	2.82%	923,766	193
8	Bangladesh	158,512,570	2.19%	1.22%	143,998	1,101
9	Russia	142,467,651	1.97%	-0.26%	17,076,310	8
10	Japan	126,999,808	1.75%	-0.11%	377,873	336
11	Mexico	123,799,215	1.71%	1.20%	1,958,198	63
12	Philippines	100,096,496	1.38%	1.73%	300,000	334
13	Ethiopia	96,506,031	1.33%	2.56%	1,104,302	87
14	Vietnam	92,547,959	1.28%	0.95%	331,689	279
15	Egypt	83,386,739	1.15%	1.62%	1,001,450	83
16	Germany	82,652,256	1.14%	-0.09%	357,021	232
17	Iran	78,470,222	1.08%	1.32%	1,648,188	48
18	Turkey	75,837,020	1.05%	1.21%	783,562	97
19	Congo	69,360,118	0.96%	2.73%	2,344,832	30
20	Thailand	67,222,972	0.93%	0.32%	513,113	131
21	France	64,641,279	0.89%	0.54%	551,500	117
22	U. K.	63,489,234	0.88%	0.56%	242,900	261
23	Italy	61,070,224	0.84%	0.13%	301,318	203
24	Burma	53,718,958	0.74%	0.86%	676,578	79
25	South Africa	53,139,528	0.73%	0.69%	1,221,037	44
26	Tanzania	50,757,459	0.70%	3.05%	945,081	54
27	South Korea	49,512,026	0.68%	0.51%	99,538	497
28	Colombia	48,929,706	0.68%	1.26%	1,138,907	43
29	Spain	47,066,402	0.65%	0.30%	505,992	93
30	Kenya	45,545,980	0.63%	2.69%	580,366	78
31	Ukraine	44,941,303	0.62%	-0.66%	603,701	74
32	Argentina	41,803,125	0.58%	0.86%	2,780,387	15
33	Algeria	39,928,947	0.55%	1.84%	2,381,685	17
34	Uganda	38,844,624	0.54%	3.37%	241,037	161
35	Sudan	38,764,090	0.54%	2.11%	1,861,510	21
36	Poland	38,220,543	0.53%	0.01%	323,251	118
37	Canada	35,524,732	0.49%	0.98%	9,970,455	4
38	Iraq	34,768,761	0.48%	2.97%	438,319	79
39	Morocco	33,492,909	0.46%	1.47%	446,548	75
40	Afghanistan	31,280,518	0.43%	2.39%	652,085	48
41	Venezuela	30,851,343	0.43%	1.47%	912,060	34
42	Peru	30,769,077	0.42%	1.30%	1,285,204	24
43	Malaysia	30,187,896	0.42%	1.58%	329,847	92
44	Saudi Arabia	29,369,428	0.41%	1.88%	2,149,717	14
45	Uzbekistan	29,324,920	0.40%	1.35%	447,401	66
46	Nepal	28,120,740	0.39%	1.16%	147,181	191
47	Mozambique	26,472,977	0.37%	2.47%	801,580	33
48	Ghana	26,442,178	0.37%	2.08%	238,534	111
49	North Korea	25,026,588	0.35%	0.53%	120,538	208
50	Yemen	24,968,508	0.34%	2.30%	527,965	47
51	Australia	23,630,169	0.33%	1.23%	7,739,983	3
52	Madagascar	23,571,962	0.33%	2.82%	587,039	40
53	Cameroon	22,818,632	0.32%	2.54%	475,438	48
54	Angola	22,137,261	0.31%	3.10%	1,246,678	18
55	Syria	21,986,615	0.30%	0.40%	185,180	119
56	Romania	21,640,168	0.30%	-0.27%	238,391	91
57	Sri Lanka	21,445,775	0.30%	0.81%	65,610	327
58	Côte d'Ivoire	20,804,774	0.29%	2.41%	322,465	65
59	Niger	18,534,802	0.26%	3.95%	1,266,990	15
60	Chile	17,772,871	0.25%	0.87%	756,614	23
61	Burkina Faso	17,419,615	0.24%	2.86%	274,001	64
62	Malawi	16,829,144	0.23%	2.85%	118,484	142
63	Netherlands	16,802,463	0.23%	0.26%	41,528	405
64	Kazakhstan	16,606,878	0.23%	1.01%	2,725,119	6
65	Ecuador	15,982,551	0.22%	1.55%	283,560	56
66	Guatemala	15,859,714	0.22%	2.53%	108,889	146
67	Mali	15,768,227	0.22%	3.05%	1,240,225	13
68	Cambodia	15,408,270	0.21%	1.80%	181,035	85
69	Zambia	15,021,002	0.21%	3.32%	752,631	20
70	Zimbabwe	14,599,325	0.20%	3.18%	390,753	37
71	Senegal	14,548,171	0.20%	2.94%	196,722	74
72	Chad	13,211,146	0.18%	3.01%	1,284,007	10
73	Rwanda	12,100,049	0.17%	2.75%	26,338	459
74	Guinea	12,043,898	0.17%	2.54%	245,859	49
75	South Sudan	11,738,718	0.16%	3.92%	644,312	18
76	Cuba	11,258,597	0.16%	-0.06%	110,861	102
77	Belgium	11,144,420	0.15%	0.36%	30,528	365
78	Greece	11,128,404	0.15%	0.00%	131,956	84
79	Tunisia	11,116,899	0.15%	1.09%	163,609	68
80	Bolivia	10,847,664	0.15%	1.65%	1,098,609	10
81	Somalia	10,805,651	0.15%	2.95%	637,652	17
82	Czech Republic	10,740,468	0.15%	0.36%	78,866	136
83	Portugal	10,610,304	0.15%	0.02%	91,982	115
84	Benin	10,599,510	0.15%	2.67%	112,622	94
85	Dominican Republic	10,528,954	0.15%	1.20%	48,511	217
86	Burundi	10,482,752	0.14%	3.15%	27,834	377
87	Haiti	10,461,409	0.14%	1.40%	27,750	377
88	Hungary	9,933,173	0.14%	-0.22%	93,032	107
89	Sweden	9,631,261	0.13%	0.63%	449,954	21
90	Azerbaijan	9,514,887	0.13%	1.08%	86,600	110
91	Serbia	9,468,378	0.13%	-0.44%	88,361	107
92	United Arab Emirates	9,445,624	0.13%	1.06%	83,600	113
93	Belarus	9,307,609	0.13%	-0.52%	207,602	45
94	Austria	8,526,429	0.12%	0.37%	83,858	102
95	Tajikistan	8,408,947	0.12%	2.45%	143,099	59
96	Honduras	8,260,749	0.11%	2.01%	112,088	74
97	Switzerland	8,157,896	0.11%	0.99%	41,284	198
98	Israel	7,822,107	0.11%	1.15%	22,145	353
99	Jordan	7,504,812	0.10%	3.18%	89,342	84
100	Papua New Guinea	7,476,108	0.10%	2.12%	462,831	16
101	Hong Kong	7,259,569	0.10%	0.77%	1,099	6,606
102	Bulgaria	7,167,998	0.10%	-0.76%	110,912	65
103	Togo	6,993,244	0.10%	2.59%	56,785	123
104	Paraguay	6,917,579	0.10%	1.69%	406,749	17
105	Laos	6,894,098	0.10%	1.84%	236,797	29
106	Eritrea	6,536,176	0.09%	3.21%	117,599	56
107	El Salvador	6,383,752	0.09%	0.68%	21,041	303
108	Libya	6,253,452	0.09%	0.84%	1,759,553	4
109	Sierra Leone	6,205,382	0.09%	1.86%	71,740	86
110	Nicaragua	6,169,269	0.09%	1.46%	130,000	47
111	Denmark	5,640,184	0.08%	0.38%	43,094	131
112	Kyrgyzstan	5,625,015	0.08%	1.40%	199,901	28
113	Singapore	5,517,102	0.08%	1.95%	683	8,078
114	Slovakia	5,454,154	0.08%	0.07%	49,033	111
115	Finland	5,443,497	0.08%	0.32%	338,147	16
116	Turkmenistan	5,307,171	0.07%	1.28%	488,105	11
117	Norway	5,091,924	0.07%	0.98%	385,168	13
118	Lebanon	4,965,914	0.07%	2.99%	10,400	477
119	Costa Rica	4,937,755	0.07%	1.35%	51,100	97
120	Central African Republic	4,709,203	0.07%	2.01%	622,993	8
121	Ireland	4,677,340	0.06%	1.08%	70,273	67
122	Congo	4,558,594	0.06%	2.49%	342,006	13
123	New Zealand	4,551,349	0.06%	1.01%	270,527	17
124	State of Palestine	4,436,411	0.06%	2.55%	6,020	737
125	Liberia	4,396,873	0.06%	2.39%	111,370	39
126	Georgia	4,322,842	0.06%	-0.42%	69,700	62
127	Croatia	4,272,044	0.06%	-0.41%	56,538	76
128	Mauritania	3,984,457	0.06%	2.43%	1,025,600	4
129	Oman	3,926,492	0.05%	8.10%	309,489	13
130	Panama	3,926,017	0.05%	1.60%	75,516	52
131	Bosnia and Herzegovina	3,824,746	0.05%	-0.12%	51,197	75
132	Puerto Rico	3,683,601	0.05%	-0.13%	8,875	415
133	Kuwait	3,479,371	0.05%	3.29%	17,818	195
134	Moldova	3,461,380	0.05%	-0.74%	33,851	102
135	Uruguay	3,418,694	0.05%	0.34%	175,012	20
136	Albania	3,185,413	0.04%	0.38%	28,748	111
137	Lithuania	3,008,287	0.04%	-0.29%	65,300	46
138	Armenia	2,983,990	0.04%	0.25%	29,800	100
139	Mongolia	2,881,415	0.04%	1.49%	1,566,838	2
140	Jamaica	2,798,837	0.04%	0.54%	10,991	255
141	Namibia	2,347,988	0.03%	1.94%	824,434	3
142	Qatar	2,267,916	0.03%	4.58%	11,000	206
143	Macedonia	2,108,434	0.03%	0.06%	25,713	82
144	Lesotho	2,097,511	0.03%	1.11%	30,355	69
145	Slovenia	2,075,592	0.03%	0.17%	20,256	102
146	Latvia	2,041,111	0.03%	-0.45%	64,600	32
147	Botswana	2,038,587	0.03%	0.86%	581,789	4
148	Gambia	1,908,954	0.03%	3.23%	11,295	169
149	Guinea-Bissau	1,745,798	0.02%	2.44%	36,125	48
150	Gabon	1,711,294	0.02%	2.37%	267,682	6
151	Trinidad and Tobago	1,344,235	0.02%	0.23%	5,130	262
152	Bahrain	1,344,111	0.02%	0.90%	694	1,937
153	Estonia	1,283,771	0.02%	-0.27%	45,100	28
154	Swaziland	1,267,704	0.02%	1.46%	17,364	73
155	Mauritius	1,249,151	0.02%	0.38%	2,040	612
156	Cyprus	1,153,058	0.02%	1.04%	9,251	125
157	Timor-Leste	1,152,439	0.02%	1.73%	14,874	77
158	Fiji	887,027	0.01%	0.68%	18,274	49
159	Djibouti	886,313	0.01%	1.53%	23,200	38
160	Réunion	885,328	0.01%	1.14%	2,510	353
161	Guyana	803,677	0.01%	0.51%	214,944	4
162	Equatorial Guinea	778,061	0.01%	2.78%	28,051	28
163	Bhutan	765,552	0.01%	1.54%	47,001	16
164	Comoros	752,438	0.01%	2.38%	1,861	404
165	Montenegro	621,542	0.01%	0.03%	13,812	45
166	Western Sahara	585,646	0.01%	3.23%	265,961	2
167	Macau	575,481	0.01%	1.61%	26	22,134
168	Solomon Islands	572,865	0.01%	2.07%	28,896	20
169	Suriname	543,925	0.01%	0.86%	163,833	3
170	Luxembourg	536,761	0.01%	1.20%	2,586	208
171	Cape Verde	503,637	0.01%	0.95%	4,033	125
172	Guadeloupe	468,016	0.01%	0.48%	1,705	274
173	Malta	430,146	0.01%	0.27%	316	1,361
174	Brunei	423,205	0.01%	1.30%	5,765	73
175	Martinique	404,705	0.01%	0.25%	1,102	367
176	Bahamas	382,571	0.01%	1.38%	13,878	28
177	Maldives	351,572	0.00%	1.90%	298	1,180
178	Belize	339,758	0.00%	2.37%	22,966	15
179	Iceland	333,135	0.00%	1.09%	103,010	3
180	Barbados	286,066	0.00%	0.50%	430	665
181	French Polynesia	279,835	0.00%	1.09%	4,000	70
182	New Caledonia	259,824	0.00%	1.30%	18,575	14
183	Vanuatu	258,301	0.00%	2.19%	12,189	21
184	French Guiana	255,455	0.00%	2.50%	90,012	3
185	Mayotte	228,070	0.00%	2.66%	374	610
186	Sao Tome and Principe	197,882	0.00%	2.53%	964	205
187	Samoa	191,831	0.00%	0.77%	2,831	68
188	Saint Lucia	183,598	0.00%	0.73%	539	341
189	Guam	167,546	0.00%	1.47%	549	305
190	Channel Islands	162,778	0.00%	0.47%	195	835
191	Curaçao	161,836	0.00%	1.94%	444	364
192	Saint Vincent and the Grenadines	109,371	0.00%	0.00%	388	282
193	United States Virgin Islands	106,792	0.00%	0.15%	347	308
194	Grenada	106,303	0.00%	0.38%	344	309
195	Tonga	105,782	0.00%	0.44%	650	163
196	Kiribati	103,942	0.00%	1.55%	726	143
197	Micronesia	103,903	0.00%	0.34%	702	148
198	Aruba	103,431	0.00%	0.51%	180	575
199	Seychelles	93,306	0.00%	0.50%	455	205
200	Antigua and Barbuda	90,903	0.00%	1.02%	442	206
201	Isle of Man	86,475	0.00%	0.68%	572	151
202	Andorra	80,153	0.00%	1.18%	468	171
203	Dominica	72,341	0.00%	0.47%	751	96
204	Bermuda	65,461	0.00%	0.18%	53	1,235
205	Cayman Islands	59,226	0.00%	1.35%	264	224
206	Greenland	57,164	0.00%	0.31%	2,198,615	0
207	American Samoa	55,320	0.00%	0.28%	199	278
208	Saint Kitts and Nevis	54,789	0.00%	1.10%	261	210
209	Northern Mariana Islands	54,531	0.00%	1.26%	464	118
210	Marshall Islands	52,772	0.00%	0.26%	181	292
211	Faeroe Islands	49,460	0.00%	-0.02%	1,399	35
212	Sint Maarten (Dutch part)	46,085	0.00%	1.88%	34	1,355
213	Monaco	38,066	0.00%	0.62%	1	25,548
214	Liechtenstein	37,194	0.00%	0.73%	160	232
215	Turks and Caicos Islands	33,736	0.00%	1.93%	430	78
216	San Marino	31,637	0.00%	0.60%	61	519
217	Gibraltar	29,335	0.00%	0.09%	6	4,889
218	British Virgin Islands	28,562	0.00%	0.78%	151	189
219	Palau	21,097	0.00%	0.86%	459	46
220	Cook Islands	20,732	0.00%	0.50%	236	88
221	Caribbean Netherlands	19,525	0.00%	2.06%	328	60
222	Anguilla	14,460	0.00%	1.12%	91	159
223	Wallis and Futuna Islands	13,206	0.00%	-0.50%	200	66
224	Nauru	10,081	0.00%	0.30%	21	480
225	Tuvalu	9,894	0.00%	0.18%	26	381
226	Saint Pierre and Miquelon	6,046	0.00%	0.05%	242	25
227	Montserrat	5,135	0.00%	0.86%	102	50
228	Saint Helena	4,120	0.00%	-0.22%	122	34
229	Falkland Islands (Malvinas)	3,052	0.00%	0.26%	12,159	0
230	Niue	1,307	0.00%	-2.75%	260	5
231	Tokelau	1,222	0.00%	2.26%	12	102
232	Holy See	799	0.00%	0.00%	0	1,816

[view full table]

World Population: Gender, Age, Fertility Rate, Immigration

(view full table)

How many people have ever lived on earth?

It was written during the 1970s that 75% of the people who had ever been born were alive at that moment. This was grossly false.

Assuming that we start counting from about 50,000 B.C., the time when modern hom*o sapiens appeared on the earth (and not from 700,000 B.C. when the ancestors of hom*o sapiens appeared, or several million years ago when hominids were present), taking into account that all population data are a rough estimate, and assuming a constant growth rate applied to each period up to modern times, it has been estimated that a total of approximately 106 billion people have been born since the dawn of the human species, making the population currently alive roughly 6% of all people who have ever lived on planet Earth.

Others have estimated the number of human beings who have ever lived to be anywhere from 45 billion to 125 billion, with most estimates falling into the range of 90 to 110 billion humans.

World Population clock: sources and methodology

The world population counter displayed on Worldometers takes into consideration data from two major sources: the United Nations and the U.S. Census Bureau.

The United Nations Population Division of the Department of Economic and Social Affairs every two years calculates, updates, and publishes estimates of total population in its World Population Prospects series. These population estimates and projections provide the standard and consistent set of population figures that are used throughout the United Nations system.
The World Population Prospect: the 2015 Revision provides the most recent data available (released on July 29, 2015). Estimates and projected world population and country specific populations are given from 1950 through 2100 and are released every two years. The latest revision has revised upwards the world population projections.
Data underlying the population estimates are national and sub national census data and data on births, deaths, and migrants available from national sources and publications, as well as from questionnaires. For all countries, census and registration data are evaluated and, if necessary, adjusted for incompleteness by the Population Division as part of its preparations of the official United Nations population estimates and projections.
The International Programs Center at the U.S. Census Bureau, Population Division also develops estimates and projections based on analysis of available data (based on census, survey, and administrative information) on population, fertility, mortality, and migration for each country or area of the world. According to the U.S. Census Bureau, world population reached 7 billion on March 12, 2012.
For most countries adjustment of the data is necessary to correct for errors, omissions, and inconsistencies in the data. Finally, since most recent data for a single country is often at least two years old, the current world population figure is necessarily a projection of past data based on assumed trends. As new data become available, assumptions and data are reevaluated and past conclusions and current figures may be modified.
For information about how these estimates and projections are made by the U.S. Census Bureau, see the Population Estimates and Projections Methodology.

Why Worldometers clocks are the most accurate

The above world population clock is based on the latest estimates released on July 29, 2015 by the United Nations and will show the same number wherever you are in the world and whatever time you set on your PC. Worldometers is the only website to show live counters that are based on UN data and that do not follow the user's PC clock.

Visitors around the world visiting a PC clock based counter, such as the the United Nations' one on http://7billionactions.org and http://ngm.nationalgeographic.com/7-billion see different numbers depending on where they are located, and therefore have seen the clock reaching 7 billion whenever their locally set PC clocks reached 4:21:10 AM on October 31, 2011. As a test, try changing the date to yesterday on your computer clock, and watch what happens to http://ngm.nationalgeographic.com/7-billion. With 39 time zones around the world, every visitor is seeing a different number right now on the United Nations clock. Look instead at Worldometers.

Obviously, the UN data is based on estimates and can't be 100% accurate, so in all honesty nobody can possibly say with any degree of certainty on which day world population reaches 7 billion (or any other exact number), let alone at what time. But once an estimate is done (based on the best data and analysis available), the world population clock should be showing the same number at any given time anywhere around the world.