> For the complete documentation index, see [llms.txt](https://learn.moselle.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://learn.moselle.io/planning-and-execution/forecasting/phase-3-refine-and-maintain/forecast-by-week.md).

# Forecast by Week

{% hint style="info" %}
**Quick Answer:** On the planning page, hover any future month and click **Forecast by week** to open the weekly view. Edit each week's projection while Moselle keeps the total tied to your monthly forecast, then click **Save weekly forecast**. Setup takes about 2 minutes.
{% endhint %}

## What Is Weekly Forecasting in Moselle?

**Weekly forecasting** lets you break a monthly forecast down into individual weeks so you can shape demand at a finer level of detail. Instead of spreading a month's demand evenly, you decide how much lands in each week — useful for promotions, launches, holidays, and any period where timing within the month matters.

### Key Benefits:

• **Plan around timing** — Place demand in the exact weeks a promotion or launch happens • **Keep totals honest** — Your weekly numbers always roll up to the monthly forecast • **Sharper replenishment** — Weekly detail feeds more precise ordering and coverage

## Prerequisites

**Time Required:** 2 minutes **Difficulty:** Beginner

Before you begin, make sure you have:

* [ ] A scenario plan with a generated forecast
* [ ] At least one **future** month in your plan (past months can't be edited)
* [ ] Your retail calendar set in Company Settings (see Step 1)

## Step-by-Step Instructions

{% stepper %}
{% step %}

### Confirm Your Retail Calendar

Weekly forecasting uses your account's retail calendar to define where each week starts and ends.

1. Go to **Settings → Company → Company Settings**
2. Find the **Retail Calendar** field
3. Confirm it is set to **ISO / Standard Calendar Week (Mon–Sun)**

**Expected Result:** Weeks in the weekly view run Monday through Sunday and are numbered by ISO week.
{% endstep %}

{% step %}

### Open the Weekly View

1. Open your scenario plan on the **Planning** page
2. Hover over a **future month** in the forecast table header
3. Click **Forecast by week**

**Expected Result:** The weekly view opens, titled **"\[Month] Weekly Forecast"**, with one column per week plus a **Monthly Forecast** column.
{% endstep %}

{% step %}

### Edit Your Weekly Projections

1. Click into any weekly cell and enter your projected demand for that week
2. Watch the **Monthly Forecast** column — it shows how your weekly numbers compare to the month's total

{% hint style="warning" %}
Your weekly values must add up to the monthly forecast. Moselle keeps the month total fixed as you edit, so raising one week means lowering another.
{% endhint %}
{% endstep %}

{% step %}

### Adjust the Monthly Total (Optional)

The **Monthly Forecast** column is read-only by default so you don't change the total by accident.

1. Hover the **Monthly Forecast** cell
2. Click **Unlock**
3. Edit the monthly total inline and confirm

**Expected Result:** The month total updates and your weekly breakdown adjusts to the new total.
{% endstep %}

{% step %}

### Save Your Weekly Forecast

1. Click **Save weekly forecast**
2. Navigate back to your plan

{% hint style="success" %}
A **blue dot** appears on any month that has a saved weekly forecast, so you can see at a glance which months are planned by week.
{% endhint %}
{% endstep %}
{% endstepper %}

## Editing or Removing a Weekly Forecast

Once a month has a weekly forecast, its header menu changes:

| Action                     | Where to Find It  | What It Does                                                              |
| -------------------------- | ----------------- | ------------------------------------------------------------------------- |
| **Edit weekly forecast**   | Month header      | Reopens the weekly view to make changes                                   |
| **Remove weekly forecast** | Month header menu | Clears the weekly detail and returns the month to a single monthly figure |

If you try to leave the weekly view with unsaved changes, Moselle prompts you to **Save** or **Discard** so you never lose an edit by accident.

## Frequently Asked Questions

### Why don't I see "Forecast by week" on a month?

Weekly forecasting is only available for **future** months. Past and in-progress months are read-only, so the option won't appear.

### Do my weekly numbers change my monthly forecast?

No. By default the monthly total stays fixed and your weekly edits are distributed within it. To change the total itself, use the **Unlock** option on the Monthly Forecast column.

### What calendar do the weeks follow?

Weeks follow the **ISO / Standard Calendar Week (Mon–Sun)** set in your Company Settings, numbered by ISO week.

### Can I remove a weekly forecast later?

Yes. Open the month's header menu and choose **Remove weekly forecast** to return that month to a single monthly figure.

## Troubleshooting Common Issues

| Problem                               | Solution                                                           | Time to Fix |
| ------------------------------------- | ------------------------------------------------------------------ | ----------- |
| "Forecast by week" is missing         | Confirm you're on a future month — past months can't be telescoped | 1 minute    |
| Weekly totals won't save              | Make sure your weekly values add up to the monthly total           | 2 minutes   |
| Can't edit the Monthly Forecast cell  | Hover the cell and click **Unlock** first                          | 1 minute    |
| Lost track of which months are weekly | Look for the **blue dot** on month headers in the plan             | 1 minute    |

## Related Guides

{% content-ref url="/pages/0j4ySH8ZiAtDK6eRiQ77" %}
[Refine Your Forecast](/planning-and-execution/forecasting/phase-3-refine-and-maintain/refine-your-forecast.md)
{% endcontent-ref %}

{% content-ref url="/pages/m7P5Z47OAkdJCWudsFQK" %}
[Customize a Forecast](/planning-and-execution/forecasting/phase-2-build-your-forecast/customize-a-forecast.md)
{% endcontent-ref %}