WHAT IS THE APPROPRIATE "TFR" IMMIGRATION RATE FOR THE U.S.?

by Duns Scotus

There is a lot of fevered, heated, and polarised debate over the question of immigration. Driven by sheer emotion, partisans on either side constantly argue from totally ludicrous and irreconcilable positions. This makes everything rather meaningless and, worse than that, tedious and sterile.

Pro-immigration activists are all about the boost to the economy, GDP, and how we need foreign workers to do the jobs "lazy" Americans don't want to do. In short they make ridiculous "economics only" arguments. Meanwhile anti-immigrant activists often lean towards unrealistic demographic pictures of sealed borders and pristine racial purity.

So, is there such a thing as a sensible Aristotelian path somewhere down the middle between the frankly moronic and soulless economic argument and the sadly unrealistic and delusional restrictionist argument?

The best that we can do is to create a sensible middle point, with which most sane people across the spectrum could partially agree. I propose that this would be to base immigration on the total fertility rate (TFR), commonly expressed as the number of children per woman.

This won't keep everyone happy but it at least gives us a rough, workable idea of where (given certain assumptions about the kind of society we have) immigration should be. Of course, those assumptions—such as prioritising GDP, maintaining population at present levels, filling certain labour shortages, and attitudes to family formation—should also be open to question.

So, basing things on TFR and the assumptions of a relatively "steady state" society and economy, what is the appropriate immigration rate for the US?

This is not a difficult calculation to make.

The US resident population reached roughly 340 million by mid-2024 (Census Bureau Vintage 2024 estimates put the July 1, 2024 figure just over 340 million; later estimates show about 341.8 million by July 1, 2025). Women of childbearing age (ages 15–44) number on the order of 65–67 million. Using 2024 birth and fertility data implies about 67.5 million: the general fertility rate was 53.8 births per 1,000 women ages 15–44 and there were 3,628,934 births, so women 15–44 ≈ 3,628,934 / 0.0538.

Meanwhile the US total fertility rate was a record-low 1.60 children per woman in 2024 (1,599.5 births per 1,000 women), down from 1.62 in 2023 (CDC/NCHS). As you need a replacement level of about 2.1 for a stable population without immigration, you can see it is well short of what it should be, and also that this creates an aging society, which makes it harder to maintain the status quo. (The US still has a modest natural increase—births exceeding deaths—unlike some peer countries, but the gap to replacement remains large.)

But exactly how much is the shortfall?

With around 67.5 million women of childbearing age, each woman needs to have roughly 0.5 more children over her reproductive lifespan, so we can estimate the number of additional births needed, following the same rough method of spreading the lifetime shortfall evenly over a 30-year reproductive window (ages 15–44):

• Annual births per woman at TFR 2.1: 2.1 ÷ 30 ≈ 0.070 children per woman per year.
• Annual births per woman at TFR 1.60: 1.60 ÷ 30 ≈ 0.0533 children per woman per year.
• Shortfall in births per woman per year: 0.070 − 0.0533 ≈ 0.0167.
• Total shortfall in births: 0.0167 × 67.5 million ≈ 1.13 million fewer births per year compared to replacement level. (Using the slightly lower replacement figure of 2.075 yields a shortfall nearer 1.07 million. Using 2023 figures—TFR 1.62 and roughly 66 million women 15–44—produces a similar order of magnitude, around 1.05 million.)

This means that the appropriate immigration rate given the US TFR, under a steady-state population assumption, is on the order of 1.1 million people annually.

Meanwhile, for the recent years overlapping this fertility picture, net international migration was far higher. Census Bureau estimates put net international migration at about 2.3 million for July 2022–June 2023 and a peak of roughly 2.7–2.8 million for July 2023–June 2024 (accounting for the large majority of that year’s population growth). It then fell to about 1.3 million in the July 2024–June 2025 period. The elevated 2021–2024 inflows are what can be called the "Bidenwave."

Once a “TFR immigration rate” of roughly 1.1 million people per year is widely accepted as a political consensus, it will then be possible to move on to other aspects of the debate, like the question of the costs and the benefits of boosting TFR and the nature and quality of immigrants. Here it could be argued that immigrants should be either highly skilled or from countries that are racially and culturally akin to America’s core population.

Also see "What is the Appropriate TFR Immigration Rate For the UK?"