Inflation is the general, sustained rise in the prices of goods and services over a period. The formula is: inflation = (CPI this period - CPI previous period) divided by CPI previous period, times 100%. Below you'll find a calculator, worked examples with numbers, and the latest Indonesian inflation data from BPS, Indonesia's statistics agency.

Key Points

• Inflation is calculated from the change in the Consumer Price Index (CPI) between two periods.
• The formula: (current CPI - previous CPI) divided by previous CPI, times 100%.
• BPS reports three figures: monthly, year to date, and year on year.
• Indonesia's annual inflation in October 2026 was 3.23%.

The Inflation Formula

Inflation (%) = (end CPI - start CPI) / start CPI x 100

The CPI (Consumer Price Index) tracks the price change of a basket of goods and services households typically buy. BPS publishes it every month.

To see how price indexes are built, read our explainer on price indexes.

Inflation Calculator

Enter two CPI values to compute inflation, or enter an amount of money to see how its value changes.

Worked Examples

The CPI numbers below are illustrative, for learning only, not official data.

Example 1: monthly inflation. January CPI is 110.00 and February CPI is 110.55. (110.55 - 110.00) / 110.00 x 100% = 0.50%.

Example 2: yearly inflation. CPI last October was 105.00 and CPI this October is 109.20. (109.20 - 105.00) / 105.00 x 100% = 4.00%.

Example 3: value of money. With 4% inflation per year for 5 years, the price factor is 1.04 to the power of 5, about 1.2167. Something that costs 1,000,000 today would cost about 1,216,653. Seen the other way, 1,000,000 buys only what about 821,927 buys today.

Monthly, Year-to-Date, and Annual Inflation

• Monthly (month to month): this month's CPI compared with last month's.
• Year to date: this month's CPI compared with the previous December.
• Annual (year on year): this month's CPI compared with the same month last year.

When a headline says "inflation of 3.23%", it usually means the annual figure.

Indonesia's Inflation Data

Source: BPS. Updated November 11, 2026 (October 2026 data, BPS release on November 2, 2026).

BPS publishes new figures at the start of each month.

Headline Inflation vs Core Inflation

Headline inflation uses every item in the CPI basket. Core inflation strips out the more volatile components, such as some food items and government-set prices, so it better reflects the medium-term trend.

How Inflation Affects Money and Assets

Inflation erodes the buying power of cash: 1 million today buys less next year. That is why many people look for assets whose value can keep pace with inflation, such as gold, stocks, or digital assets. No asset protects your money automatically, and every choice carries its own risk.

Further reading:

• Inflation and purchasing power
• How inflation affects digital assets

Follow the Digital Asset Market on Mobee

If you want to see how digital assets move, you can look at the BTC-IDR pair on Mobee Spot Trade. Mobee is operated by PT CTXG Indonesia Berkarya, which is licensed and supervised by OJK. Install the Mobee app to follow the market and start with an amount that fits your budget.

Conclusion

Calculating inflation takes two CPI values and one formula. Use the calculator above to practice, then compare with the official BPS figures released each month. Understand the difference between monthly, year-to-date, and annual figures so you don't misread the news.

FAQ

What is the inflation formula?

Inflation is (end CPI minus start CPI) divided by start CPI, then multiplied by 100%.

What is the CPI?

The CPI is the Consumer Price Index, a measure of the price change of a basket of goods and services households typically buy. BPS publishes it every month.

What is the difference between monthly, year-to-date, and annual inflation?

Monthly compares with last month, year to date compares with the previous December, and annual compares with the same month last year.

What is Indonesia's latest inflation rate?

According to BPS data, annual inflation for October 2026 was 3.23% and monthly inflation was 0.22%.

How do I calculate the value of money after inflation?

Divide the amount by (1 + inflation rate) raised to the number of years. For example, 1,000,000 at 4% inflation for 5 years is worth about 821,927 in today's buying power.

Disclaimer

This article is for education and is not financial or investment advice. Example numbers are illustrative, and official data comes from BPS. Crypto assets are high risk. Do your own research before making decisions. Mobee is operated by PT CTXG Indonesia Berkarya, licensed and supervised by OJK.