Thailand’s rate of natural increase (RNI)—the difference between birth and death rates, excluding migration—has declined significantly in recent decades, reflecting broader demographic transitions in Southeast Asia. As of the early 2020s, Thailand’s RNI is low, at around 0.1% per year, indicating a near-stable or slowly growing population. This contrasts sharply with neighboring countries such as Cambodia and Laos, where the RNI remains higher, at approximately 1.4% and 1.7% respectively, due to higher birth rates and younger populations. On the other hand, Thailand’s RNI is similar to that of Vietnam, which has also experienced rapid fertility decline and now has an RNI of about 0.8%. Meanwhile, Myanmar’s RNI is somewhat higher than Thailand’s but is also on a downward trend. These differences are largely due to variations in economic development, family planning policies, and social changes, with Thailand being among the first in the region to undergo a demographic transition to low fertility and mortality rates.
| Year | Rate of Natural Increase | Population |
|---|---|---|
| 1990 | 1.34 | 56,096,722 |
| 1995 | 1.259 | 58,880,563 |
| 2000 | 0.818 | 61,146,322 |
| 2005 | 0.683 | 63,982,612 |
| 2010 | 0.498 | 66,271,488 |
| 2015 | 0.381 | 68,067,372 |
| 2020 | 0.282 | 69,291,926 |
| 2024 | 0.197 | 69,920,998 |
| 2025 | 0.174 | 70,025,248 |
| 2026 | 0.15 | 70,109,971 |
| 2030 | 0.053 | 70,280,684 |
| 2035 | -0.08 | 70,086,586 |
| 2040 | -0.215 | 69,428,181 |
| 2045 | -0.351 | 68,308,383 |
| 2050 | -0.473 | 66,768,316 |
| 2055 | -0.569 | 64,901,811 |
| 2060 | -0.635 | 62,828,177 |
| 2065 | -0.67 | 60,662,463 |
| 2070 | -0.678 | 58,504,654 |
| 2075 | -0.668 | 56,423,303 |
| 2080 | -0.654 | 54,443,487 |
| 2085 | -0.643 | 52,562,240 |
| 2090 | -0.635 | 50,764,568 |
| 2095 | -0.623 | 49,045,065 |
| 2100 | -0.599 | 47,424,266 |
Data from US Census International Database