Absolute and relative difference
How much two values differ, in units and in per cent.
Fill in the fields and the result will appear here automatically.
Shows both differences at once: the plain subtraction and its size relative to the starting value. The denominator is the absolute value of the base, so a rise from a negative number reads as growth rather than as a negative percentage.
How it works
Formula and logic
Absolute = after − before. Relative = that difference divided by the absolute value of before, times 100.
Example
From 120 to 150: signed difference +30, relative difference +25%. From −50 to 50: +100 and +200%, because the base is |−50|. From 0 to 5: difference +5 with no relative percentage.
Fields and units
- Before — unitless
- After — unitless
How to use
- — Enter the original value in Before and the new value in After.
- — Use the same units for both values; negative numbers are supported.
- — Read the signed difference and the percentage relative to the absolute original value; a zero base has no relative percentage.
Method and limitations
- Calculation method
- Formula and logic
- Limitation
- Here “absolute” means a signed difference in units, not the magnitude of the difference. A zero base has no relative percentage.
FAQ
How is this different from percentage change?
Percentage change divides by the base itself. Here the divisor is its absolute value, so growth from a negative number reads as positive.
Why is relative difference missing sometimes?
When the starting value is zero there is nothing to divide by, so only the absolute difference exists.
Which value is the base?
The first one — the value you started from. Swapping the two changes the percentage.
Can both values be negative?
Yes. The absolute difference keeps its sign and the relative one is measured against the size of the base.