# Week over Week Calculator

URL: https://speedycalculator.com/calculators/finance/week-over-week/
Last updated: 2026-10-25

> The week over week calculator works out the percentage change of a metric from one week to the next, and the average weekly compound growth rate over several weeks.

## Inputs

- Value in the initial week
- Value in the following week
- Value after several weeks
- Number of weeks between initial and that value

## Results

- Week over week change
- Absolute change
- Weekly compound growth rate
- Annualized (52 weeks) at that growth

## Formula

```
WoW change = (this week − last week) ÷ last week × 100
Weekly compound growth = (final ÷ initial)^(1 ÷ weeks) − 1
```

## Explanation

Startups and marketers track week-over-week growth to spot trends quickly. Y Combinator famously suggests 5–7% weekly growth as a strong target for early startups – which compounds to 12–33× a year.

### How to use the Week over Week Calculator

- **Value in the initial week**
- **Value in the following week**
- **Value after several weeks**
- **Number of weeks between initial and that value**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Enter the value in the first week and the following week, and optionally a value several weeks later.

### Tips

- Use the nominal annual rate and pick the compounding frequency your bank or broker states.
- Small differences in return or fees compound into large differences over decades.
- Run the calculation with a cautious, a central and an optimistic return to see the range of outcomes.
- Past returns do not guarantee future returns – nothing here is investment advice.

### Common mistakes to avoid

- Comparing an APR with an APY or effective rate.
- Ignoring inflation, taxes and fees when judging a real return.
- Entering a percentage as a decimal (5 instead of 0.05 is correct here).

### Inputs explained

FieldWhat to enterValue in the initial weekA numberValue in the following weekA numberValue after several weeksA numberNumber of weeks between initial and that valueA number

### What each result means

- **Week over week change** = ([Value in the following week] - [Value in the initial week])÷[Value in the initial week]×100
- **Absolute change** = [Value in the following week] - [Value in the initial week]
- **Weekly compound growth rate** = (([Value after several weeks]÷[Value in the initial week])^(1÷[Number of weeks between initial and that value]) - 1)×100
- **Annualized (52 weeks) at that growth** = ((1 + [Weekly compound growth rate]÷100)^52 - 1)×100

### Example values

How the main result changes when **Value in the initial week** changes and everything else stays at the example values above:

Value in the initial weekWeek over week change (%)60011590043.331,2007.51,500-141,800-28.332,400-46.25

## Worked example

Inputs — Value in the initial week: 1,200; Value in the following week: 1,290; Value after several weeks: 1,800; Number of weeks between initial and that value: 6.

Results — **Week over week change = 7.5 %**; Absolute change = 90; Weekly compound growth rate = 6.99 %; Annualized (52 weeks) at that growth = 3,258.34 %.

## FAQ

**How do I calculate week over week growth?**
(This week − last week) ÷ last week × 100.

**What is a good weekly growth rate?**
For early startups, 5–7% a week is considered strong.

**Why use compound growth over several weeks?**
It smooths week-to-week noise.

**What formula does the Week over Week Calculator use?**
WoW change = (this week − last week) ÷ last week × 100.