Census Population Projection Calculator

Work out census population projection instantly with clear inputs, formula shown and shareable results.

About Census Population Projection Calculator

Population projection compounds the natural growth rate — births less deaths — and then adds net migration each year. Doubling time follows from the growth rate alone and is a useful sanity check: 1% growth doubles a population in about 70 years.

Formulas

Geometric growth

Population = Current x (1 + Growth rate)^Years, plus net migration each year

Doubling time

Doubling years = ln(2) / ln(1 + Growth rate)

Worked example

With the default values below, Census Population Projection Calculator returns Projected population of 1,675,413,980. Change any input above and every figure here is recalculated in your browser.

Inputs used

Current population: 1,420,000,000
Annual growth rate: 0.85
Projection horizonaccepts 0–1,000 years: 20 years
Net annual migration: -300,000

Results

Projected population: 1,675,413,980
Projection from natural growth alone: 1,681,924,107
Doubling time at this growth rate: 81.9
Total change over the horizon: 255,413,980

Step by step

1Values used
2Geometric growth
3Doubling time
4Projected population= 1,675,413,980
5Projection from natural growth alone= 1,681,924,107
6Doubling time at this growth rate= 81.9
7Total change over the horizon= 255,413,980

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax or fees or charges into account.
Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Indicative estimate only. Fees, entitlements, limits and formulas vary by jurisdiction, statute, policy wording and the facts of the case. This is not legal, tax, insurance or financial advice — confirm with a qualified professional or the relevant authority.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Indicative estimate only. Fees, entitlements, limits and formulas vary by jurisdiction, statute, policy wording and the facts of the case. This is not legal, tax, insurance or financial advice — confirm with a qualified professional or the relevant authority.

Frequently Asked Questions

Why does a small growth rate matter so much?

Because it compounds. The difference between 0.5% and 1.5% growth over 50 years is roughly a 60% difference in final population.

Is a constant growth rate realistic?

No. Fertility declines with development, so cohort-component projections with age-specific rates are used for serious demographic work.