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The short answer
The cost of one block is the cost of a production batch (cement, sand, water, labour, and a share of equipment and yard costs) divided by the number of good blocks it produces after breakages. The Nigerian Industrial Standard mix cited for sandcrete blocks is 1:8 cement to sand, which works out at about 20 hollow 225 mm blocks per bag with manual compaction, so cement is usually the biggest single cost and the one you must not cut.
Block moulding looks simple: cement, sand, water, a mould. The money is in the detail. A yard that guesses its cost per block can sell thousands a week and still not make money, especially when cement prices move. This guide shows how to cost a block properly, with a worked example you can copy with your own prices.
The standard you are building to
Structville, a Nigerian engineering site, summarises the Nigerian Industrial Standard for sandcrete blocks (NIS 87:2007) as follows:
- Minimum strength, load-bearing
- 3.45 N/mm²
- Minimum strength, non-load-bearing
- 2.5 N/mm²
- Common sizes
- 450 × 225 × 225 mm (9-inch) and 450 × 150 × 225 mm (6-inch)
- Recommended mix
- 1 part cement to 8 parts sand
- Expected yield (225 mm hollow, 1:8, manual compaction)
- About 20 blocks per bag
- Curing
- At least 14 days
These figures matter for costing because the temptation is always to stretch a bag into more blocks. A yard that makes far more blocks per bag than the mix allows will look cheaper on paper but risks producing blocks below the minimum strength. Price for the standard, and tell builders that is what they are buying. Check the full standard with the Standards Organisation of Nigeria if you need the exact test methods.
The cost lines
| Cost | How to measure it |
|---|---|
| Cement | Price per 50 kg bag, including transport to the yard |
| Sand | Price per tipper load divided by the number of bags' worth of batches it makes |
| Water | Borehole running cost or water purchased, per batch |
| Labour | Per block paid to moulders, or daily wages divided by blocks made |
| Equipment | Machine or moulds, generator, wheelbarrows: cost spread over their useful life |
| Yard | Rent, security, power, divided by monthly output |
| Breakages | Blocks lost in demoulding, curing, stacking and loading |
| Delivery | Truck, fuel, loaders: price separately per trip |
Measure sand by batches, not by guesswork. Count how many bags of cement you mould from one tipper load over a few loads; that ratio is your real sand cost per batch. Fine sand with too much silt or clay weakens blocks, so cheap sand can cost more in rejected work.
Worked example: cost per block
Two things stand out. Cement is about 59% of the batch cost in this example (9,500 ÷ 16,000), so a ₦1,000 rise in the bag price adds about ₦53 to each block (1,000 ÷ 19). And breakages are expensive: losing 2 blocks per batch instead of 1 raises cost per block to about ₦889 (16,000 ÷ 18).
Your own yield is the number that matters, so measure it. The 20-blocks-per-bag figure is for manual compaction of 9-inch hollow blocks; a vibrating machine, a different block size or a different sand will give a different count. Record bags used and good blocks produced every day for two weeks, take the average, and use that in your formula. If your yield is well above the standard figure, test some blocks for strength before you advertise the price.
Setting and holding a price
- Recalculate when cement moves. Keep a one-line formula: your fixed batch costs plus today's cement price, divided by your good-block yield.
- Quote ex-yard and delivered separately. Delivery cost depends on distance and road; price it per trip and show it on its own line.
- Give quotes a validity period, for example seven days, so a price rise does not leave you supplying a large order at a loss.
- Price 6-inch and 9-inch separately. They use different amounts of material per block; cost each from its own yield.
- Compare with the market last. Market prices tell you what builders will pay, not what you need. Our city guides, such as Onitsha building materials prices, help with the comparison.
Records and tax
Keep a daily production log: bags used, blocks made, blocks broken, blocks sold. It tells you your real yield and catches cement going missing. Many block yards are small enough to fall under the Nigeria Tax Act 2025 small business VAT exemption (turnover up to ₦100 million and fixed assets up to ₦250 million), per Forvis Mazars; check your own figures each year. Your profit is taxable either way.
Where Pryme fits
A Pryme Business Account lets you send invoices with ex-yard and delivery lines and receive payment by bank-transfer checkout. If you sell to builders on credit, read selling blocks on credit.
Questions people ask
How many blocks can one bag of cement make?
For 225 mm (9-inch) hollow blocks at the 1:8 mix recommended under NIS 87:2007, Structville gives about 20 blocks per bag with manual compaction. Making many more per bag risks blocks below the minimum strength.
How do I calculate the cost of one block?
Add the cost of one batch (cement, sand, water, labour, and a share of equipment and yard costs) and divide by the number of good blocks it produces after breakages.
What is the standard strength of sandcrete blocks in Nigeria?
NIS 87:2007, as summarised by Structville, sets minimum compressive strength of 3.45 N/mm² for load-bearing and 2.5 N/mm² for non-load-bearing blocks.
How long should blocks cure before sale?
At least 14 days, according to Structville's summary of recommended practice.
Sources
- Structville: sandcrete blocks, production, specifications and testing (14 Jul 2022) · accessed Oct 2026
- Forvis Mazars: 2025 NTA, key VAT changes for business (16 Mar 2026) · accessed Oct 2026
This article is general information, not financial, legal or tax advice. Products described are provided under the terms on this site and are subject to regulation and eligibility.