> For the complete documentation index, see [llms.txt](https://docs.besmarthead.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.besmarthead.com/ghg-emissions-co2-calculator/calculator-drawer.md).

# Calculate a row: emission factors and sources

Calculate one GHG row from a few emission factors and as many sources as you like – 100 vehicles, 3 factors, one total that flows into your disclosure.

A GHG row – say **Mobile combustion** – is the sum of your sources: every car, truck or fuel invoice, each multiplied by an emission factor. The row calculator keeps the factors and the sources apart, so you pick a factor once and reuse it for every source that needs it.

{% hint style="success" %}
**Saves you time:** few factors, many sources. A fleet of 100 cars needs three factors (diesel, petrol, electric), not 100 searches. Select the cars, **Assign emission factor**, done.
{% endhint %}

## Where to find it

Open the disclosure (**E1-8**, **E1-6**, **B3** or **C3**), find the row and click the small calculator icon right after the unit. It is tiny – hover the end of the row and look for the **CO2 Calculator** tooltip.

![one E1-8 table row with the calculator icon after the unit highlighted](https://2593582272-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FxT5TFLiwBWeM9d0fDydH%2Fuploads%2FWQngQWVD94mljFHxibT3%2Fghg-6.png?alt=media)

The drawer carries the row's name as its title. At the top: **Cancel**, **Add** (this is the save button – it confirms the row and closes the drawer), and a **"…"** menu with **Export to XLSX**, **Import from XLSX** and **Clear**. Below: the **Total** card and two tabs, **Sources (n)** and **Emission factors (n)**.

A new row opens on **Emission factors** with the hint "No emission factors yet. Add the factors you need, then the sources that use them." A row that already has sources opens on **Sources**.

## Step by step

{% stepper %}
{% step %}

### Add the factors you need

On **Emission factors**, click **Add** next to a suggestion under **Suggested emission factors · Slovakia 2026** (your country and year), or **+ Add emission factor** to search the database or define your own. Each new factor gets a color dot and one empty source. Give it a short name – you pick factors by that name later. See [Find the right emission factor](/ghg-emissions-co2-calculator/emission-factors.md).

![Emission factors tab with factor rows and the Suggested emission factors block](https://2593582272-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FxT5TFLiwBWeM9d0fDydH%2Fuploads%2F5AUeTz0HFf48i2wPw3jv%2Fghg-2.png?alt=media)
{% endstep %}

{% step %}

### Add your sources

On **Sources**, click **+ Add source**. Fill in a description ("Škoda Octavia, 2BA 123"), choose the factor from the dropdown and enter the quantity with its unit – litres, kWh, km, kg. Factors based on passengers or weight over distance ask for two quantities (passengers × km). Spend-based factors take money in the currency of your invoice.
{% endstep %}

{% step %}

### Check the result

Every source shows its t CO₂eq at the end of the row; the **Total** card adds them up. A source without a factor is not calculated – the tab warns you: "Sources without an emission factor: n. They are not calculated."
{% endstep %}

{% step %}

### Click Add

The drawer closes, the row shows the total with a calculator icon and becomes read-only. The disclosure page saves it for you.
{% endstep %}
{% endstepper %}

## The Sources tab

| Control                    | What it does                                                                                                                                     |
| -------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------ |
| Search field               | Finds sources "by description or emission factor".                                                                                               |
| Filter dropdown            | **All sources**, **Without emission factor**, or one factor – the fastest way to see what still needs a factor.                                  |
| **Select all**             | Selects every source the search and filter show.                                                                                                 |
| **Assign emission factor** | Gives the selected sources one factor in one go. A source with a value keeps it when the unit type fits – 12 000 km stay 12 000 km.              |
| **Remove selected**        | Removes the selected sources after a confirmation.                                                                                               |
| **Show more (50)**         | The list shows 50 sources at a time.                                                                                                             |
| Row **"…"** menu           | **Duplicate** (the fastest way to add a similar vehicle), **Remove**, **Split using template** (split one source by site or your own breakdown). |

![Sources tab with search, filter, selected sources and Assign emission factor](https://2593582272-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FxT5TFLiwBWeM9d0fDydH%2Fuploads%2FrMsDKJqVpF9u9alIyC8G%2Fghg-1.png?alt=media)

## The Emission factors tab

Each factor is one line: the database badge (**BEIS / 2026**, **IPCC / 2019**, or **Custom**), its name, the factor value and unit, the number of its sources, and their subtotal.

* **Rename** by clicking the name. The hint says it all: "Give the new emission factors a short name, e.g. Diesel car. You choose them by this name in the sources and in Excel."
* **Color dot** – each factor has one of eight colors; the same dot sits in front of the factor in every source, so a wrong factor jumps out.
* **Sources count** – the tooltip reads "Sources with this emission factor: n. Click to show them." It opens the Sources tab filtered to that factor.
* **"…" menu** – **Add source** with this factor; **Change emission factor** replaces it with another one and recalculates all its sources; **Remove** keeps the sources but leaves them without a factor ("Its n sources will stay without an emission factor and won't be calculated").
* Hover the badge or the name for the details: activity, source dataset, region, year.

## Tips

* **Cars first works too.** Import your vehicle list from Excel without factors, then filter **Without emission factor**, **Select all**, **Assign emission factor**. See [Fleet and site lists via Excel](/ghg-emissions-co2-calculator/excel.md).
* **Duplicate** a source and change only the plate number and the mileage.
* **Clear** in the drawer menu removes everything in the row – factors and sources – after a confirmation. Use it to restart a row, not to remove one source.
* An empty source (no description, no quantity) disappears when you click **Add**, so the empty source that comes with a new factor never clutters your list.

## Good to know

* **Who:** administrators, and reporters with a request on the data point, edit. Auditors and viewers see the drawer without **Add**.
* **Cancel** discards everything you changed since you opened the drawer; SmartHead asks first.
* A row that is split by a breakdown (site, country) has no calculator on the parent – calculate the child rows.
* Rows saved with the older calculator keep it (TO CHECK Q9 on [GHG emissions in SmartHead](/ghg-emissions-co2-calculator/ghg.md)).

## Related

{% content-ref url="/pages/ipL8b8pqbT82Mw7tWgI7" %}
[Find the right emission factor](/ghg-emissions-co2-calculator/emission-factors.md)
{% endcontent-ref %}

{% content-ref url="/pages/xtNInE9ddj8xIwHtDCp6" %}
[Fleet and site lists via Excel](/ghg-emissions-co2-calculator/excel.md)
{% endcontent-ref %}

{% content-ref url="/pages/Txd27aBKU1SmtsBIOnyX" %}
[Breakdowns: split a value by site, country or gender](/working-with-your-data/breakdowns.md)
{% endcontent-ref %}

{% content-ref url="/pages/iABtywiMb8odU9ANyWIv" %}
[Everything you can do on a data point](/working-with-your-data/datapoint.md)
{% endcontent-ref %}