Compute the week-over-week percentage change, absolute change, and compounded weekly growth rate between two values a given number of weeks apart.
Input Data
Results
At a glance:WoW is the percentage change between the two values; the compounded weekly growth rate annualises that change over the number of weeks.
Formula
wow = (following − initial) / initial × 100%
change = following − initial
weeklyCagr = (following / initial)^(1 / weeks) − 1
$$WoW = \dfrac{Following - Initial}{Initial} \times 100\%$$$$Change = Following - Initial$$$$Weekly\ CAGR = \left(\dfrac{Following}{Initial}\right)^{1/weeks} - 1$$How to Use
- Enter the initial and following week values.
- Enter the weeks between them.
- Review the WoW change, absolute change, and weekly growth rate.
FAQ
What is the difference between week-over-week (WoW) and month-over-month (MoM)?
The calculation is the same (new value minus old value, divided by old value); only the time unit differs—WoW compares adjacent weeks, MoM compares adjacent months. WoW captures short-term swings and trends more sensitively.
Why look at the compounded weekly growth rate?
A single WoW change reflects only adjacent weeks; if you want the average pace across several weeks, the compounded weekly growth rate spreads the total change evenly over each week, giving a fairer picture of the sustained growth pace.
What does a negative result mean?
A negative number means the following week is below the initial week, i.e. the indicator fell. For example −20% means this week's value is 20% below last week's.
How is the compounded weekly growth rate calculated, and why can't I just add the weekly changes?
The compounded weekly growth rate (weekly CAGR) formula is: (ending week ÷ initial week)^(1 ÷ weeks between) − 1. It spreads the whole period's total change 'evenly and compounded' across each week, yielding a stable equivalent weekly pace. You cannot simply add or take the arithmetic average of the weekly percentage changes because growth compounds—each week's growth builds on the already-changed base of the prior week, and those bases differ. Example: if an indicator rises from 10,000 to 14,641 over 4 weeks, total growth is 46.41%; intuition may say '÷ 4 ≈ 11.6% a week', but the correct compounded weekly rate is (14,641 ÷ 10,000)^(1/4) − 1 = 10% (since 1.10^4 = 1.4641). Note the compounded figure (10%) is below the arithmetic average (11.6%), the gap coming from the rolling effect of compounding. With this calculator, just enter a number greater than 1 in 'weeks between' to get this fairer sustained-growth rate automatically.
What should I watch when analysing WoW data, and what is WoW good for?
WoW's biggest strength is speed—it spots short-term changes in sales, web traffic, share price, app DAU and similar metrics within days, suiting operations that need close monitoring and fast response (e.g. e-commerce promotions, early app launches, marketing-campaign tracking). But precisely because the period is short, WoW is also especially 'noisy'; watch several points. First, week-internal structure and holidays: a week contains weekends and weekdays; if a week hits a public holiday (e.g. Lunar New Year, Christmas) or has only a few working days, values naturally dip and a comparison to a normal week distorts. Second, one-off events: a big promotion, a viral post, a large order or a refund can spike or crash a single week without signalling a trend change. Third, avoid over-reacting: don't rush to change strategy on one down week; watch several consecutive weeks (a moving average) before judging direction. Fourth, pair with longer periods: read WoW together with MoM and YoY so short, medium and long trends corroborate and a single week's swing doesn't mislead. In short, WoW is a sensitive 'short-term thermometer'—but interpret it within a longer trend context.
Content review: Calculatorism Finance Team. Results are for reference only; please refer to the relevant authorities for the official figures.