Kitchen renovation cost estimate screenshot from Remodelum

Home Addition Cost Calculator (2026)

Estimate the cost to add living space—bedrooms, sunrooms, or convert a garage — with zip-code level accuracy and manage the budget once construction starts.

Estimate My Addition Remodel Budget
Manage a live addition remodel budget

Why most renovation cost estimates fall short

  • No two renovations are the same.

    The cost of a renovation depends on the scope, the condition of the property, and the decisions made along the way. Generic averages can’t account for these differences.

    Remodelum tailors each estimate to the specifics of your project and the current state of the property — not just the type of renovation.

  • Renovation costs vary dramatically by location.

    Labor rates, material pricing, and permitting costs differ from one market to another. That’s why national averages often miss the mark.

    Remodelum uses zip-code level data to tailor renovation cost estimates, reflecting local conditions rather than broad assumptions.

  • A lump-sum estimate doesn’t help you make decisions.

    When planning a renovation, tradeoffs are unavoidable — materials vs. labor, finishes vs. scope, budget vs. timeline. Without a breakdown, it’s impossible to understand where money is going.

    Remodelum provides a detailed, category-level estimate so you can evaluate tradeoffs and compare contractor quotes more effectively.

  • Estimating is only the beginning.

    Once a renovation starts, costs change. Materials get adjusted, scope shifts, and new decisions appear. An estimate that lives in isolation quickly becomes outdated.

    Remodelum turns your estimate into a live renovation budget — so the same breakdown you plan with is the one you track as work progresses.

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More than an estimator

Room additions often involve structural work, permits, and scope changes. Costs can shift quickly once construction begins.

Remodelum lets you turn your estimate into a live budget — tracking actual expenses, payments, and invoices as the project progresses.

Typical 2026 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

Tracking these expenses during the renovation is where most homeowners lose visibility.

Remodel Tracker
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

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

Planning a Renovation? Make sure you document your investment!

Every roof replacement, kitchen remodel, HVAC upgrade and addition increases your cost basis. A clean capital improvements log will help you keep your property’s market value and reduce your taxable gain when you sell .

Investment Record

Already renovating?

You can skip estimating and start tracking costs and payments after signup.

Manage my live renovation

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

 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.

What type of renovation do you want to calculate?