What Is Week Over Week (WoW)?
Week over week (WoW) is a comparison of a metric from one week to the immediately preceding week. It is widely used in analytics, sales, marketing, finance, and operations to spot short-term trends, measure the impact of a campaign, or track recurring performance. Because weekly cycles smooth out daily noise (like weekday vs. weekend swings), WoW comparisons give a cleaner read on momentum than day-over-day numbers.
How to Use This Calculator
Enter the value from last week and the value from this week. The calculator returns the percentage change, the absolute change, and an echo of both inputs. A positive percentage means growth; a negative percentage means decline. Works for revenue, users, clicks, sign-ups, page views, or any weekly number.
The Formula Explained
The core equation is:
$$\text{WoW \%} = \frac{\text{This Week} - \text{Last Week}}{\text{Last Week}} \times 100$$
First subtract last week's value from this week's value to get the absolute change. Then divide by last week's value to express that change relative to the starting point, and multiply by 100 to convert it into a percentage. If last week's value is zero, percentage change is undefined (division by zero), so the calculator returns 0 in that case.
Worked Example
Suppose your website had 100 sign-ups last week and 120 sign-ups this week. The absolute change is \(120 - 100 = 20\). The percentage change is $$20 \div 100 \times 100 = \textbf{20\%}.$$ Your sign-ups grew 20% week over week.
FAQ
What does a negative WoW% mean? It means this week's value is lower than last week's — a decline. For example, going from 200 to 150 is a \(-25\%\) change.
Why use WoW instead of month over month? WoW reacts faster, helping you catch sudden shifts (a viral post, an outage, a promotion) before a monthly report would reveal them.
What if last week was zero? Percentage change can't be computed from a zero base, since dividing by zero is undefined. In that situation, look at the absolute change instead.
