Council Executive gave their backing to proposals which would see construction start on the new school in April 2023.
Due to rising construction costs, a fixed price of £18.3 million has been agreed to remove additional financial risks.
The current East Calder Primary School building is not suitable for the future delivery of high-quality education due to a number of issues including suitability, accessibility and sustainability.
The plans will see a new school constructed adjacent to the existing school in Langton Road, East Calder, with the recently built Early Years extension retained.
Once complete in 2024, pupils will move over to the new building and the current school will be demolished.
Executive councillor for education Andrew McGuire said: "I'm delighted that work is set to start on a superb new East Calder Primary School soon.
"We are committed to delivering the best possible platform for education for children in West Lothian by continually improving our school estate.
"Educational attainment has been rising consistently for the last decade in West Lothian, and making sure we have buildings suitable for learning is a key part of this.
"In a challenging and volatile construction market, agreeing a fixed price of £18.3 million for the new school provides certainty for the council and the local community going forward."
The project is being delivered on behalf of the council by Hub South East with Morrison Construction as the Tier-1 contractor. This is the same partnership that recently delivered the new Winchburgh Schools development, West Calder High School and Calderwood Primary in East Calder.
It is jointly funded by Scottish and Local Government as part of the Learning Estate Investment Programme.
