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How to Sell Products by Weight or Volume (per kg, per 100 g, per litre)

Summary: Sell by Weight / Volume prices a product per base quantity (for example per 100 g or per 1000 g) so the Qashier POS works out the price from the measured quantity your staff enter. Made for seafood, meat, fruit, bulk goods and drinks sold by the millilitre or litre.

Applies to: All markets · set up in QashierHQ (or in the Qashier POS product editor) · sold on Qashier POS · an account with access to Product Management.

How it works

You give the product a Price, a Base Quantity and a Unit. At the POS, the quantity entered is treated as a multiple of the base quantity.

  • Example from QashierHQ: Price $2 per 100g, POS quantity 1.2 → 120g → $2.40.

  • Example: Chilli Crab at 100 per kilogram. Set Price 100, Base Quantity 1000 and Unit g. When staff enter 1.2, the POS charges 1.2 × 100 = 120 and shows the item as "Chilli Crab (1200g)".

Prices are in your store currency. Quantities are typed in by staff; they are not read from a scale.

Set it up in QashierHQ

  1. Log in to QashierHQ. In the left menu, under Products & Inventory, click Product Management, then choose the store.

  2. Select the tab, click the category, then click the product. The Edit Product dialog opens.

  3. Expand Advanced Settings.

  4. Under Unit Settings, tick Sell by Weight / Volume.

  5. Enter the Base Quantity (a whole number, for example 1000) and the Unit (for example g, kg, ml or L). The Price shown beside them is the product's price per base quantity.

  6. Click Confirm.

You can set the same options while creating a product, under Advanced Settings in the Add Product dialog.

On the Qashier POS product editor (☰ > Manage Products), the same setting is called Unit-based Quantity, with Unit Name (e.g. g, ml, pcs) and Unit Scale (e.g. 100 for 100g).

How it works on Qashier POS

  1. Tap the product. The item dialog shows the rate in the product name, for example "Chilli Crab (S$100.00/1000g)", and a Unit (1000g) field.

  2. Enter the measured quantity as a multiple of the base quantity, for example 1.2 for 1200 g.

  3. Add the item. The POS multiplies the price by the quantity entered and shows the converted quantity in the order, for example "Chilli Crab (1200g)".

Good to know

  • Each weighed item is added as its own line in the order; two weighings of the same product never merge into one line.

  • If a price tier, member price or open price applies, that price is used as the base and multiplied by the quantity entered. Item discounts apply to the calculated price.

  • The order records the item with a quantity of 1 and stores the weight or volume separately.

If something goes wrong

What you see

Cause

What to do

The POS adds the product at its fixed price with no Unit field

Sell by Weight / Volume is not ticked, or the terminal has not synced.

Check the product in QashierHQ, then keep the POS online so it can sync the change.

"Required" under Base Quantity

The field is empty or 0.

Enter a whole number greater than 0.

The price looks 10× too high or too low

The base quantity does not match the price, for example a per-kg price with base quantity 100.

Set Base Quantity to the amount the price is for (1000 for a per-kg price with unit g).

Still stuck? Contact Qashier support.

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Last verified: 25 Sep 2026 · Markets: All markets

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