---
title: "About these money-and-time calculators | Interest Grove"
description: "What Interest Grove is: free inflation and compound-growth calculators built on BLS CPI data, run in your browser, for education only."
url: https://interestgrove.bond/about/
---

# About Interest Grove

Five small calculators about money and time: what inflation did, what it does, and how growth compounds.

## What it is

Interest Grove answers everyday questions about money over time: what an old price is in today's dollars, how much buying power cash loses, how long money takes to double, what regular saving grows to, and how much of a return is left after inflation. Each page shows its formula and names its sources, from the U.S. Bureau of Labor Statistics' price index to Irving Fisher's 1930 book on interest.

## Educational use only

It is educational and not financial advice. The calculators work out the numbers you give them; they do not recommend any investment, account, fund or provider. Rates you enter are assumptions for illustration, and the example values are neutral starting points, not forecasts. Past inflation does not predict future inflation. Interest Grove is not a bank or any other financial institution and has no link to one.

## The price data

The inflation, purchasing power and real return calculators use the Consumer Price Index for All Urban Consumers (CPI-U), U.S. city average, all items, not seasonally adjusted: BLS series CUUR0000SA0. The annual averages for 1913 to 2025 were fetched from the BLS Public Data API on 30 October 2026 and are stored in the page exactly as published; nothing is estimated or projected.

## How it works

Everything runs in your browser. The formulas and the price data are part of the page, so nothing you type is sent anywhere, and once a page has loaded it keeps working without a connection. There are no accounts, cookies or ads.