Gas Price Change Calculator: Change Between Two Prices
Work out the percentage change between two pump prices — what the gas station is asking now versus what it asked a week, month, or year ago.
Adjust the inputs and select Calculate for a full breakdown.
Compare Common Scenarios
How the numbers shift across typical situations for this calculator:
| Scenario | Price change | Cents/dollar change |
|---|---|---|
| $3.20 to $3.68 | 15.00% | 0.48 |
| $4.50 to $3.95 | -12.22% | -0.55 |
| $2.80 to $3.20 | 14.29% | 0.4 |
| $3.50 to $5.00 | 42.86% | 1.5 |
How This Calculator Works
Enter the earlier and the current pump price per gallon. The calculator subtracts one from the other for the dollar change and divides by the earlier price to give the percentage. The result is the total change between the two dates.
The Formula
Percentage Change
Old is the starting value, New is the ending value
Worked Example
Gas rising from $3.20 to $3.68 a gallon is a 15% increase — about 48 cents more per gallon. On a 12-gallon fill, that is roughly $5.76 extra each time you tank up.
Key Insight
Pump prices swing more than most consumer prices because crude oil, refining margins, and seasonal blends all move on their own clocks. A short window can look dramatic; pull back to a year for a fairer read on the trend.
Frequently Asked Questions
How is the gas price change calculated?
Subtract the earlier price from the current price for the dollar change, divide by the earlier price, and multiply by 100 for the percentage change.
Why are gas prices so volatile?
Crude oil prices, refining capacity, seasonal gasoline blends, taxes, and local supply all move pump prices. A change at the refinery shows up at the pump within days.
Is this an annual rate?
No. It is the total change between two dates. To compare against inflation, divide by the number of years between the prices.
How much more am I paying per fill-up?
Multiply the dollar change by the tank size you fill. A 50-cent rise on a 12-gallon tank is roughly $6 more each visit.
Are gas prices included in inflation?
Yes. Gasoline is a tracked category in the Consumer Price Index, and large swings can move the headline inflation number on their own.
Related Calculators
Methodology & Review
The change is the new price minus the old price; the percentage is that change divided by the old price. The figure is total between the two dates, not an annual rate.
Written by Ugo Candido · Last updated May 17, 2026.