Granny Flat Cost Calculator

Get an instant indicative price for your granny flat project. Central Coast, Lake Macquarie, Newcastle and Hunter homeowners.

Important: This calculator provides an indicative estimate only. Actual costs depend on your specific site conditions (slope, access, services), finishes, council requirements, and bushfire compliance. For a binding fixed-price quote, contact us with your address and we'll visit the site within 7 days.

1. Choose Your Design Size

2. Site Conditions

3. Finishes

4. Compliance

Understanding Your Estimate

This calculator uses our 2025 base rates for turnkey granny flat construction on the Central Coast, Lake Macquarie, Newcastle and Hunter regions. The estimate includes:

  • Design + engineering + certification: Full architectural plans, structural engineering, BCA compliance, energy rating.
  • CDC or DA lodgement + approval: We handle the full council application process.
  • Site preparation: Excavation, footings, slab (assumes standard soil conditions — rock adds $5,000-$15,000).
  • Construction: Timber frame, Colorbond roof, external cladding (brick veneer or weatherboard), windows, doors.
  • Fit-out: Kitchen (cabinets, benchtops, appliances), bathroom (vanity, shower, toilet, tiles), internal laundry, lighting, fans.
  • Services: Electrical, plumbing, HVAC (assumes standard service runs — long runs add $3,000-$8,000).
  • Finishes: Painting (internal + external), flooring (tiles + carpet or hybrid), joinery.
  • Landscaping: Basic turfing + concrete paths (excludes retaining walls, extensive gardens, or pool-adjacent work).

What's NOT Included

  • Rock excavation: If your site has rock, excavation costs jump by $5,000-$15,000 (depends on depth and access).
  • Retaining walls: Slopes requiring retention add $3,000-$12,000 per wall (engineer-designed).
  • Long service runs: If your granny flat is 30m+ from the main house, add $3,000-$8,000 for electrical + plumbing trenching.
  • Bushfire compliance: BAL-12.5 or higher adds $8,000-$15,000 (ember guards, non-combustible cladding, fire-rated glass).
  • Luxury upgrades: Premium appliances (Miele, Bosch), stone benchtops (Caesarstone, marble), underfloor heating, ducted air-con, smart home systems.
  • Site-specific challenges: Asbestos removal, contaminated soil remediation, heritage overlays, flood zone compliance.

Next Steps

For a binding fixed-price quote:

  1. Fill out our contact form: Include your address, desired design (1, 2, or 3 bed), and any site challenges (slope, access, bushfire zone).
  2. We'll visit your site within 7 days: Brad or a project manager will assess soil, slope, services, and council requirements.
  3. You'll receive a lump-sum quote within 7 business days: Fixed price, no hidden fees, no surprises. Valid for 30 days.

Request Your Fixed-Price Quote