Quantity Surveying & Approximate Cost Guide Module 4: The Art of Turning Quantities into Cost — Unit Prices and Cost Analysis

From Quantity to Cost: Why Unit Prices Matter

A quantity only becomes meaningful when it is associated with a unit price. Without unit prices, a list of quantities is simply technical data. With unit prices, it becomes a financial roadmap for the entire project.

Every construction activity — no matter how small — must be clearly defined and priced. This is done through work items, each representing a specific construction task performed under defined conditions.

For example, “painting” is not a sufficient definition. A proper work item describes:

• Surface condition
• Number of coats
• Type of paint
• Application method

This level of clarity ensures that everyone involved — designers, contractors, and project owners — is pricing the same work.

Official Unit Prices: The Industry Baseline

In many projects, especially large-scale or publicly funded ones, pricing is based on official unit price catalogs. These catalogs provide standardized descriptions and prices for thousands of construction activities.

While these catalogs bring consistency and fairness, they also introduce practical challenges:

• Thousands of pages to search
• Multiple years and revisions
• Different institutions publishing similar items with subtle differences

Manually navigating these documents is time-consuming and increases the risk of selecting incorrect or outdated prices.

Modern digital platforms eliminate this friction by centralizing unit price libraries, keeping them up to date, and allowing quantities to be matched with prices in seconds instead of days.

What Is Unit Price Analysis?

A unit price is not an arbitrary number. Behind every unit price lies a detailed cost analysis that explains exactly how that price was formed.

Unit price analysis answers a simple but critical question:

What does it really take to produce one unit of work?

The Building Blocks of a Unit Price

Every unit price analysis is composed of three main cost groups:

1. Materials

All consumable materials required to complete one unit of work, including waste allowances.

2. Labor

The time required by skilled and unskilled workers to complete the task, based on realistic productivity rates.

3. Equipment

Machinery, tools, and auxiliary equipment needed to perform the work.

Each of these components is quantified and multiplied by current market prices. The sum of these costs forms the base cost of the work item.

To this base cost, overheads and contractor profit are added, resulting in the final unit price.

A Simple Example: Interior Painting

To better understand unit price analysis, consider interior wall painting per square meter:

• Materials: primer, paint, consumables
• Labor: painter and helper time
• Equipment: hand tools and accessories

Each input is calculated separately and combined to form the base cost. After adding overhead and profit, the final unit price is obtained.

This same logic applies whether the work item is painting one square meter of wall or pouring one cubic meter of reinforced concrete.

When Official Prices Are Not Enough

Not every project fits neatly into standardized price lists. Modern construction increasingly involves:

• Custom materials
• Branded systems
• Specialized installation techniques

In such cases, custom unit price analyses must be prepared.

This process involves:

1. Clearly defining the work item
2. Listing all required materials, labor, and equipment
3. Collecting current market prices through supplier quotations

These analyses are critical not only for pricing but also for defending costs during audits, negotiations, and progress payments.

The Manual Pricing Problem

Traditionally, converting quantities into cost involves repetitive manual steps:

• Searching for the correct unit price
• Copying values into spreadsheets
• Repeating calculations for each revision
• Updating prices when catalogs change

As project size grows, this approach becomes increasingly fragile. A single mistake in unit price selection or formula application can distort the entire budget.

This is one of the biggest hidden risks in cost estimation.

How Approx Transforms Cost Estimation

Approx approaches pricing differently.

Instead of treating quantities and prices as disconnected data, Approx links them through structured logic:

• Quantities are calculated once, consistently
• Unit prices are selected from centralized libraries
• Cost analyses are transparent and reusable
• Changes propagate automatically across the project

This means:

• Faster budget preparation
• Fewer manual errors
• Greater confidence in cost decisions

What once took weeks can now be completed in days — with significantly higher reliability.

Bringing It All Together: Cost Summaries

By the end of this module, quantities and unit prices come together to form cost summaries.

For example:

• Concrete quantity × concrete unit price
• Painting area × painting unit price
• Installation count × installation unit price

These summaries reveal:

• Where the budget is concentrated
• Which items carry the highest risk
• Where optimization opportunities exist

At this point, the project’s financial structure becomes fully visible.

What’s Next?

Now that we know how much work there is and how much each unit costs, the next step is to assemble everything into a complete cost estimate and approximate project budget.

In the next module, we will focus on building comprehensive cost summaries, evaluating totals, and understanding how these figures are used in procurement and decision-making.