# Home Addition Cost

> For 400 sq ft, the current national model estimates $97,599, with a planning range of $74,175 to $138,591. Adjust project size and quality, then enter a ZIP to apply a metro or state wage factor to labor only. Materials, labor, permits, disposal, data dates, and sources are shown separately.

Canonical calculator: https://homecosttotals.com/home-addition-cost/  
Category: Interior remodel  
Baseline date: 2026-01-01  
Reviewed: 2026-08-14

## National default result

- **Typical:** $97,599
- **Planning range:** $74,175 to $138,591
- **Default quantity:** 400 sq ft
- **Per unit:** $244 per sq ft
- **Components:** materials $51,568, labor $39,431, permits $3,800, disposal $2,800

The national default is a planning estimate, not a contractor quote. A ZIP changes the labor component using a metro or state OEWS wage multiplier; it does not change materials.

## Inputs

- **Addition area:** default 400 sq ft
- **Material / quality:** default standard

## Calculation

    material = baseline material rate × quantity × material index change × quality
    labor = baseline labor rate × quantity × labor index change × ZIP wage multiplier
    subtotal = material + labor + permit + disposal
    range = subtotal × documented low/high multipliers

Material index: PCU423300423300, latest period 2026-07-01, change 9.25%.  
Labor index: PPIFIS, latest period 2026-07-01, change 2.69%.

## Main price drivers

- Room or project size
- Finish and material tier
- Layout and structural changes
- Trade coordination and access
- Permits, demolition, and disposal

## Sources

- [U.S. Bureau of Labor Statistics — May 2025 OEWS](https://www.bls.gov/oes/tables.htm) — retrieved 2026-08-14; United States. Limitation: Employee wages exclude contractor overhead, benefits, profit, and project-specific scarcity.
- [U.S. Census Bureau — Value of Construction Put in Place](https://www.census.gov/constructionspending) — retrieved 2026-08-14; United States. Limitation: Broad construction spending is used only as a direction and plausibility check.
- [Harvard Joint Center for Housing Studies — Remodeling Futures](https://www.jchs.harvard.edu/research-areas/remodeling-futures) — retrieved 2026-08-14; United States. Limitation: Market-level remodeling research is used for corroboration, not line-item pricing.

## Questions and direct answers

### What does this home addition cost include?

The estimate separates materials, labor, permit, and disposal using the quantities shown. It excludes financing, hidden damage, and optional work not selected.

### How does the ZIP adjustment work?

ZIP is matched to a metro when available; otherwise a state wage factor is used. Only labor changes. Materials remain tied to national price indices.

### Is this a contractor quote?

No. It is a planning estimate. Confirm scope, code requirements, and price with licensed local contractors before committing funds.

### Why is the range wider than the typical cost?

The low and high multipliers capture ordinary variation in finish level, access, site conditions, and contractor availability.

### How current is the estimate?

The baseline is dated 2026-01-01. Index observations and their latest periods are displayed with every result.

### Can I use the result for a budget?

Use it as an early planning range and include contingency. A site-specific quote remains necessary for a committed budget.

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