Population Growth Calculator

How to use this calculator

Enter Earlier population, Later population, Years elapsed. The result updates in your browser as you edit an input. The prefilled values are examples only.

How the estimate works

Divide population change by earlier population. The annualized rate assumes compound growth.

What can change the answer?

Compare the same geographic boundary and consistent population series. A boundary change can look like population growth even when residents did not move.

Before relying on the result

Check that both figures describe the intended geographic boundary and reference period. Confirm units, source definitions and any uncertainty information in the original dataset. The calculator does not independently verify those details or explain the causes of a change.

Further reference

For source data or a more detailed method, see U.S. Census Bureau: QuickFacts. The calculator does not automatically import data from this source.

Worked example with the default inputs

An increase from 100,000 to 108,000 people is 8,000 people and 8%. Over five years, the compound annualized rate is about 1.55%. The endpoint calculation does not reveal each intervening year.

Interpret the result in a planning record

The population growth calculator compares an earlier population with a later one. It shows percentage change, the absolute difference and an annualized compound rate for the years entered. Make sure the two populations describe the same geographic boundary. A city annexation can alter the count without representing the same kind of change as growth inside a fixed area.

Save the input values, units and result together. Change one uncertain input at a time so you can see which assumption moves the answer. A displayed decimal is arithmetic precision, rather than evidence that the measurements or rates are equally precise.

More tools

Read the How to Compare US Counties Without Misreading the Data guide →