Units of Measurement and Base UOM
UOM means Unit of Measurement: the unit used to describe a quantity, such as Piece, Box of 12, Kilogram, or Liter.
In Effective POS, each product has exactly one Base UOM. This is the unit used to keep its stock balance. Other UOMs describe how many base units are in one selling or purchasing unit.
For example, a store can buy soap by the box and sell it by the piece. Both operations use the same soap stock, counted in pieces.
The three fields to understand
| Field | Meaning | Example |
|---|---|---|
| UOM Name | What one unit represents | Box of 12 |
| Multiplier | How many base units are in one of this UOM | 12 pieces per box |
| Price (₱) | Selling price for one of this UOM | ₱110 per box |
The Base UOM always has multiplier 1. Each product needs exactly one base row. The multiplier converts quantities; it does not calculate your selling price.
Stock movement in base units = quantity entered × selected UOM multiplier.
The app uses your configured multiplier. Naming a row “Box of 12” does not automatically set its multiplier to 12.
Example: pieces, packs, and boxes
Suppose you sell soap with these units. These prices are examples before any discount or tax calculation.
| UOM Name | Base UOM? | Multiplier | Selling price for one unit |
|---|---|---|---|
| Piece | Yes | 1 | ₱10 |
| Pack of 6 | No | 6 | ₱55 |
| Box of 12 | No | 12 | ₱110 |
If you physically have 10 boxes of 12, your opening stock allocation is 120 pieces, because Piece is the Base UOM. Entering 10 in the stock allocation would mean only 10 pieces.
Starting from 120 pieces:
| Sale | Quantity entered | Selected UOM | Stock deducted | Remaining stock |
|---|---|---|---|---|
| Two boxes | 2 | Box of 12 | 2 × 12 = 24 pieces | 96 pieces |
| Three individual pieces | 3 | Piece | 3 × 1 = 3 pieces | 93 pieces |
| One pack | 1 | Pack of 6 | 1 × 6 = 6 pieces | 87 pieces |
These UOMs share one stock balance. You do not allocate separate stock to the Piece, Pack, and Box rows. With 11 pieces remaining, there is enough for individual sales or a pack of 6, but not a full box of 12.
The box price can be lower than 12 times the piece price. Enter the intended price on each row; the app does not derive it from the multiplier.
Example: rice sold by weight
You can choose Kilogram as the Base UOM and enable Allow Fractional / Decimal.
| UOM Name | Base UOM? | Multiplier | What quantity 1 means |
|---|---|---|---|
| Kilogram | Yes | 1 | 1 kg |
| Bag of 25 kg | No | 25 | 25 kg |
With 100 kg in stock, selling 0.250 Kilogram deducts 0.250 kg, leaving 99.750 kg. Selling 1 Bag of 25 kg then deducts 25 kg, leaving 74.750 kg.
Measured quantities support up to three decimal places. Whole-unit products require whole quantities in the selected UOM. For example, use 6 Piece rather than 0.5 Box of 12 when selling loose pieces from a whole-unit product.
Choose a practical base unit that your staff can consistently count or measure. Kilogram is often easier for rice; Piece is often easier for individually sold packaged goods. You do not have to choose the smallest possible physical unit.
Configure a product's UOMs
As Admin, open Products → Add Product, or edit a product before using its new unit configuration.
- Find Units of Measurement (UOM).
- Enter the base row's UOM Name and Price (₱).
- Select Set Base on that row. Its button becomes Base UOM, and its multiplier is fixed at 1.
- Select Add UOM Row for each pack, box, or other unit.
- Enter each row's name, multiplier relative to the base, and selling price.
- Add optional barcodes for the relevant units. A piece and a box can have different barcodes; scanning the box barcode adds one box.
- Set Allow Fractional / Decimal according to whether staff may enter fractional quantities.
- Enter warehouse stock allocations in the Base UOM. Check the form's Allocated in: label.
- Review the conversions and save the product.
Before trading, check one example of each unit in the cart, including its quantity, unit price, and required stock. Barcode assignments must be unique.
Use the correct unit at checkout
Adding a product normally starts with its Base UOM. Choose the intended unit from the cart's unit selector, then check the quantity and total. Scanning a unit-specific barcode selects its associated UOM.
For 2 boxes, enter quantity 2 with Box of 12 selected. Do not enter 24 boxes: that would request 288 pieces. Changing the selected UOM changes what the entered quantity represents, so always recheck it.
Purchasing, receiving, and opening imports
On a purchase order, enter the quantity and purchase cost for the selected purchasing UOM. For example, quantity 10 with Box of 12 selected means 10 boxes. A purchase cost of ₱84 means ₱84 per box, making the line total ₱840.
Receiving those 10 boxes adds 120 pieces to stock. The receipt converts the box cost to a base cost of ₱7 per piece for valuation. Purchase cost and selling price are separate values.
The opening CSV import creates one Base UOM with multiplier 1. Its quantity, selling price, and opening unit cost all refer to that base unit. Add other UOMs through product editing afterward if needed.
Avoid these common mistakes
- Entering boxes in a piece-based stock allocation. Convert the physical count to pieces first.
- Using a multiplier of 1 for every unit. A box with multiplier 1 consumes only one base unit, regardless of its name.
- Expecting pack prices to calculate themselves. Enter the price for each UOM explicitly.
- Creating separate products just for different pack sizes of the same goods. Use UOM rows when those packs should share stock. A different product is appropriate when the goods themselves are different.
- Changing the Base UOM after stock exists without reconciling quantities. Selecting a different base row does not automatically convert existing stock balances. Ask the Admin to plan and verify the change before saving it; review every multiplier and warehouse quantity.
Continue with Sales and receipts, Products and inventory, or Purchasing.