---
title: How to keep a bill of materials
url: https://tideswell.xyz/docs/purchasing/bills-of-materials
description: Write down what it takes to make one unit of a product, so every production order for it starts with its components filled in.
---

> Documentation index: fetch https://tideswell.xyz/llms.txt to discover every page before exploring further.

# How to keep a bill of materials



A **bill of materials** is the recipe for one product you make: every component that goes into
one unit, and how much. Recipes live at **Buying › Bills of materials**. A production order for
that product copies its recipe when it starts, per <Ref to="purchasing/production-orders" />.

At Fairgreen Golf Co., the recipe for a Classic headcover in Navy is 0.4 m of canvas, one zip and
one woven label. Priya Raman wrote it once, and every headcover run since has started with those
three lines.

## Before you start [#before-you-start]

You need the **Store** and **Bills of materials** modules on in **Settings › Modules**, per
<Ref to="workspace-admin/modules" />. **Bills of materials** has its own switch, so a workspace can
track runs without keeping recipes.

Recipes use the production order rows on **Settings › Permissions**: **View production orders** to
read them and **Edit production orders** to write them. Both start at member.

## How do you write a recipe? [#how-do-you-write-a-recipe]

Press **New recipe** on **Buying › Bills of materials**, search for the product the recipe makes,
and pick it. The recipe opens headed "What it takes to make one" and the product's name.

1. Press **Add component**.
2. Type the **Component** name, such as Canvas, and the **Amount** for one unit, such as 0.4.
3. Type the **Unit**, such as m. Leave it as **each** for things you count.
4. Pick the **Usual supplier** if you buy it from one, or leave **No usual supplier**.
5. Add the other components the same way, then press **Save**.

Each product has one recipe. Picking a product that already has one is refused with "This product
already has a recipe."

## How do you type amounts? [#how-do-you-type-amounts]

As a plain number with a full stop for decimals, such as 0.9. Amounts can be fractions, like 0.9 m
of canvas. A decimal comma such as 0,9 is refused, with "Write the amount as a number, like 0.9."

## What happens to runs when you change a recipe? [#what-happens-to-runs-when-you-change-a-recipe]

Nothing, for runs already started. The recipe says so: "A run copies this list when it starts.
Changing it here only affects runs started afterwards."

To bring a run in line with a changed recipe, open the run and press **Reload from recipe** above
its components, per <Ref to="purchasing/production-orders" />.

## How do you reuse a recipe for another colour? [#how-do-you-reuse-a-recipe-for-another-colour]

Press **Copy to another colour** on the recipe and pick the other product, such as Classic
headcover, Green. The new recipe gets a copy of the same components, ready to adjust.

Save your changes first. Unsaved changes are not copied, and the window says so.

## How do you start a run from a recipe? [#how-do-you-start-a-run-from-a-recipe]

Press **Start a run** on the recipe. The **New production order** window opens with the product
already picked and its components listed. See <Ref to="purchasing/production-orders" />.

## What does the recipe list show? [#what-does-the-recipe-list-show]

One row per recipe, with **Makes**, **SKU**, **Components** and **Updated**. A recipe's own page
also lists its **Open runs** by order number, and under **Finished** how many runs have finished
and how many units they made.

## Do recipes go to Shopify? [#do-recipes-go-to-shopify]

No. A recipe lives in Tideswell only. When a run finishes, only the finished units are added to
Shopify, never the components.