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Building Cost Estimator

How to estimate construction costs.

Updated on

interiors of a house
Interiors of a modern house. PHOTO | FILE

Preparing financially for your upcoming construction project becomes more manageable with a preliminary a grasp on the expected costs for your new house.

Quite often, the easiest way to estimate building costs is by using tools like a building cost estimator, also known as a house construction cost calculator.

However, this guide will help you calculate and plan for the expenses associated with your construction project, even without a building estimation calculator.

Here is how to estimate your building costs.

1. Count the square footage

Look at new houses that are similar to the one you envision. Get the price of the house, subtract the price of the land, and divide that amount by the square footage of the home.

If the house is worth Sh50m and the land costs Sh25m, then the construction cost is Sh25m. If the home is 450 square metres, then the cost per square metre is about Sh55,500.

2. Consider the finishes

Note that high quality finishes significantly increase the building costs. A modest house in Nairobi goes for about Sh30,000 to Sh45,000 per square metre – with a high-end one going for about Sh50,000 to Sh80,000 per square metre.

3. Interior features

The interiors of a house greatly influence building costs. Increasing the size and number of windows, use of vaulted ceilings and high roof pitches can significantly raise costs. The quality of roofing materials will also have an impact on costs.

RELATED: The Average Cost of Building a House in Kenya

4.) Size of the home

The size of a house is also an important consideration. The cost per square foot is often higher for a smaller home compared to a larger home.

When building a bigger house, the cost of pricey items such as a bathroom and kitchen is distributed over more square footage.

DIY Building Cost Calculator

RELATED: Best Apps for Construction Calculators

Construction cost estimate formula:

  1. Total cost = Buildup area x Approximate cost per sq. ft.

Example: 1,000 x Sh4,500 = Sh20.25m

  • Amount of cement required = Buildup area x 0.4

Example: 1,000 x 0.4 = 400 bags of cement

  • Amount of sand required = Buildup area x 0.816

Example: 1,000 x 0.816 = 816 tonnes of sand

  • Amount of aggregate required = Buildup area x 0.608

Example: 1,000 x 0.608 = 608 tonnes of aggregate

  • Amount of steel required = Buildup area x 4

Example: 1,000 x 4 = 4,000 kilos of steel

  • Amount of paint required = Buildup area x 0.18

Example: 1,000 x 0.18 = 180 litres of paint

  • Number of bricks required = Buildup area x 8

Example: 1,000 x 8 = 8,000 pieces of bricks

Editor’s Note: Consult a quantity surveyor for accurate budget estimates in the pre-contract stage, and for cost control and planning during construction.

Janet Mutegi holds a degree in Architecture from the University of Nairobi. Her wealth of practical experience from working on major projects across Kenya makes her a valuable asset to our team.