Kitchen renovation cost estimate screenshot from Remodelum

Home Addition Cost Calculator (2025)

Estimate the cost to add living space—bedrooms, sunrooms, or convert a garage. Adjust size and finish to see itemized labor & materials, permits, and tie-ins; then save, export, and track your budget.

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Typical 2025 costs by addition type

  • New foundation/footings, exterior tie-ins, insulation, drywall, electrical

  • Glazing, roofing, structural support, insulation (for 4-season), HVAC options

  • Insulation, fire separation, egress/egress windows, slab leveling, electrical

  • Just tell us what you want to do and we will tailor the estimate to your needs

Renovation Guide
Home addition estimate tailored to the client's needs - remodelum output

What moves the price the most

Leverage Remodelum’s algorithm, based on data from thousands of additions and renovations and homeowners, to obtain an cost estimation tailored to your specific project and broken down by cost category

Main cost categories of your room addition

Room addition and renovation tool

  • This includes site survey, soil testing, excavation, grading, and other site-related work required for the addition

  • This includes pouring the foundation, installing footings, framing, roofing, and other structural work necessary for the addition

  • This includes siding, roofing, windows, doors, and other exterior finishes to match the existing house

  • This includes insulation, drywall, flooring, paint, and other finishes for the interior of the addition

  • This includes installing new heating, ventilation, and air conditioning systems

  • This includes work for lighting, outlets, and appliances

  • his includes installing new plumbing fixtures, piping, and connections for the addition

  • This includes decorative finishes, such as trim work, paint, flooring, and cabinetry, to complete the look of the addition

Save, export & track your budget

Create a free account to save estimates, export line items, share read-only scopes, and track invoices and changes as your project progresses.

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Estimate Costs for Every Kind of Addition

  • For bedrooms, bathrooms, and bonus rooms

  • Add a new story to your property

  • Additional number of stories for your property

  • Add a patio, deck, sunroom or other

  • Home addition cost estimator by square footage

 FAQs

  • Room additions typically range from $120 to $250 per square foot, depending on location and materials.

  • Yes, second-story additions cost more—usually $200 to $400 per square foot—due to structural engineering and roofing modifications.

  • asic single-room additions with minimal plumbing and finishes are usually the most cost-effective.

  • Yes, most jurisdictions require building permits for room or home additions. Your contractor should factor this into your estimate.

  • Second-story additions often require structural reinforcements and cost more per square foot. Use the calculator to compare both scenarios instantly.

  • Yes, Remodelum supports different room types, including sunrooms, garages, and master suites.

  • Yes. You can estimate costs without signing up. Optionally, create a free account to save and compare estimates.

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