The Day the Scale and the App Disagree
A customer walks into your gas shop with a small cylinder and ₦2,000. Cooking gas is selling around ₦1,600 per kilo, so you set the cylinder on your digital scale, open the valve, and stop the fill when the scale reads 1.25 kg. The customer pays and leaves happy.
Then you open your sales app to record it, and the quantity box refuses “1.25”. Whole numbers only. Do you record 1 kg and let a quarter kilo vanish from your records? Record 2 kg and let the app believe you sold gas you still have? Or skip the record entirely and promise yourself you will “balance it later”?
Every trader who sells by weight or measure knows this squeeze. It is why we built the “Sold by weight or measure” toggle in SabiBooks. One of our merchants, a cooking gas retailer, asked for it directly: his customers buy 1.5 kg, 2.5 kg, and 12.5 kg refills all day, and his records could not follow the scale. Once we built it for gas, we saw that the same switch serves every trade that sells by measure, from filling stations to fabric sellers.
Who Sells by Measure in Nigeria?
More Nigerian businesses sell by measure than by piece. Look at the prices these trades were posting as at September 2026:
| Trade | How they sell | Price picture (September 2026) |
|---|---|---|
| Cooking gas retailers | Per kilogram, weighed on a scale | Around ₦1,600 per kg in Lagos; a 12.5 kg refill near ₦20,000 |
| Filling stations | Per litre, from the pump | Petrol between ₦1,400 and ₦1,450 per litre in most cities |
| Fabric sellers | Per yard, cut with tape and scissors | Ankara from about ₦2,500 per yard; lace far higher |
| Frozen food and meat sellers | Per kilogram on a scale | Chicken, turkey, and beef weighed per customer |
| Paint and oil dealers | Per litre, decanted into kegs | Groundnut oil, kerosene, and paint all move in part-litres |
| Foodstuff sellers with a scale | Per kilogram | Rice, beans, garri, and crayfish weighed to order |
The pattern in every one of these shops is the same: the customer names an amount of money, the seller measures out goods to match it, and the quantity almost never lands on a whole number. ₦2,000 of gas is 1.25 kg. ₦5,000 of petrol is about 3.5 litres. A blouse takes 1.5 yards.
A sales app built only for cartons and tins tells all of these businesses the same thing: your trade does not fit here.
What Whole-Number Records Cost You
Rounding feels harmless on one sale. Across a trading day it breaks your three most useful numbers: stock on hand, daily sales, and profit.
Take a gas retailer selling 30 refills a day at an average of 2.5 kg each. The scale dispenses 75 kg of gas. If the app only accepts whole numbers and the seller rounds each sale down to 2 kg, the records say 60 kg left the tank:
| What the scale did | What the records say | |
|---|---|---|
| Refills in a day | 30 | 30 |
| Gas dispensed | 75 kg | 60 kg |
| Missing from the records daily | – | 15 kg |
| Missing in a week | – | 105 kg, about ₦168,000 of gas at ₦1,600 per kg |
After one week, the app believes the tank holds 105 kg of gas that is already in customers’ cylinders. The low-stock warning stays quiet while the tank runs dry. The profit report looks better than reality because the recorded cost of goods is too low. And when you do a physical stock count, the shortfall looks like theft, so you start suspecting staff over gas that was sold honestly and recorded badly.
Rounding up instead does the opposite: the app declares you out of stock while the tank still has gas, and your sales figures inflate. Either way, once you stop trusting your records, you stop keeping them.
Some traders cope by creating fake products, one called “Half kg”, another called “Quarter kg”, and selling combinations of them. It works until you try to read a stock report assembled from fractions pretending to be products.
Turning On “Sold by Weight or Measure”
In SabiBooks, selling by measure is one switch on the product, and you choose it product by product.
- Open Products and tap the product, or tap + to create a new one.
- On the product form, find the toggle named “Sold by weight or measure”. Under it, the app explains: “Lets you sell amounts like 12.5 kg of gas or 1.5 yards of cloth.”
- Switch it on.
- Set the Unit field to how you measure: kg, g, L, or ml. The unit prints on your receipts next to the amount.
- Set your Selling Price as the price per unit, for example ₦1,600 per kg.
- Save.
Products you leave alone keep behaving exactly as before: whole numbers only, so a shop assistant cannot accidentally sell 0.5 of a tin of milk. If someone tries to type a decimal on a normal product, SabiBooks stops them and says the quantity “must be a whole number”, pointing them to the toggle if the product genuinely sells by measure.
What Changes When You Sell
With the toggle on, the whole chain follows the scale:
- At the point of sale, the quantity box accepts decimals. Tap the product into the cart, tap the quantity, and type 12.5 or 1.25 or 27.35. Quantities can carry up to 3 decimal places.
- On the receipt and invoice, the customer sees the real amount with its unit, “12.5 kg” at ₦1,600 per kg, not a rounded “12” or “13”. The same applies to invoice PDFs you send on WhatsApp.
- In your stock, the count drops by exactly what you sold. Sell 1.25 kg from 50 kg and the app shows 48.75 kg remaining.
- In stock adjustments, you can add or remove fractional amounts too. New delivery of 250 kg? Damaged 3.5 kg? Record it as it happened.
- In low-stock alerts, the reorder level can also be fractional, so a gas seller can ask for a warning at 37.5 kg.
- In reports, daily sales and profit figures add up the exact quantities, so the number you see at night matches the money in the drawer.
You type the quantity yourself; SabiBooks does not connect to your scale or pump. The habit that matters is reading the scale and entering what it says.
Set-Up Ideas for Your Trade
A few starting points, using one product per thing you measure:
| Your trade | Product name | Unit | Price you enter | A typical sale |
|---|---|---|---|---|
| Gas retailer | Cooking Gas Refill | kg | ₦1,600 per kg | 2.5 kg for ₦4,000 |
| Filling station | Petrol (PMS) | L | ₦1,400 per L | 15.5 L for ₦21,700 |
| Frozen food seller | Turkey | kg | ₦4,500 per kg | 1.8 kg for ₦8,100 |
| Fabric seller | Ankara, per yard | – | ₦3,000 per yard | Quantity 1.5 for ₦4,500 |
| Oil dealer | Groundnut Oil | L | ₦3,200 per L | 0.75 L for ₦2,400 |
Two tips from these rows. First, price the unit deliberately: your per-kg or per-litre price should already carry your margin, because it now gets multiplied by exact quantities. Second, if your measure is not in the unit list, like yards, put the measure in the product name (“Ankara, per yard”) so every receipt still reads clearly.
If You Sell by Derica, Mudu, or Paint Bucket
Not every measure trade needs the toggle. Nigerian markets run on container measures: the derica cup, named after the old tomato-tin brand, the mudu in the North, which holds roughly 1.5 kg of grain filled to a heap, and the paint bucket, which holds about five dericas.
Nobody sells half a derica. The container is the unit, and customers buy 1, 2, or 6 of it. If that is your trade, leave the toggle off, create your product as “Rice (derica)” or “Garri (paint bucket)”, and sell whole numbers the way you always have. The whole-number rule is protecting your records there, not fighting them.
The toggle is for trades where the measuring tool has a needle, a meter, or a tape: anywhere the true amount can land between two whole numbers.
What This Feature Does Not Do Yet
We would rather tell you the edges now than let you find them mid-sale:
- No scale or pump connection. Quantities are typed by hand, as covered above.
- CSV import stays whole numbers. If you import products from a spreadsheet, quantities in the file must be whole numbers for now. Create or edit the product in the app to set a fractional starting stock.
- No separate dealer pricing yet. If you sell to bulk buyers at a different rate, an owner or manager can adjust the price on a sale line by line. Saved price lists per customer group are on our list.
How SabiBooks Helps
The measure toggle comes with the SabiBooks your shop already runs on, at no extra cost: sale recording, receipts you can share on WhatsApp, customer credit tracking, low-stock alerts, expense tracking, and profit reports. Even without network, the app opens and lets you look up your products, customers, and past sales. You can start on the free plan, and turning the toggle on for your gas, fuel, or fabric products changes nothing else about how you sell.
For the full step-by-step reference, with every field explained, see the products and inventory guide in our docs.
The Bottom Line
If you sell by kilogram, litre, gram, or yard, your records should speak the same language as your scale. An app that only takes whole numbers forces you to choose between accurate money and accurate stock, and many traders respond by giving up on records altogether.
Turn on “Sold by weight or measure” for the products you weigh and measure, keep it off for the ones you count, and let every sale enter the book exactly as it happened. Your stock count and your profit report are only as good as the quantities behind them, and those quantities can now match the scale.
