# Square Footage Calculator

- **URL:** https://codeasystem.com/calculators/construction/square-footage-calculator/
- **Category:** construction
- **Description:** Add up to three rectangular sections to find total square footage, with acre equivalents for land-scale projects.
- **Primary output:** Total square footage: 825 square feet

## Inputs
- Section 1 length (name: `length1`, type: number, example: 30)
- Section 1 width (name: `width1`, type: number, example: 20)
- Section 2 length (optional) (name: `length2`, type: number, example: 15)
- Section 2 width (optional) (name: `width2`, type: number, example: 15)
- Section 3 length (optional) (name: `length3`, type: number, example: )
- Section 3 width (optional) (name: `width3`, type: number, example: )

## Outputs
- Total square footage: 825 square feet
- Acres equivalent: 0.0189 acres
- Square yards: 91.67 sq yd
- Sections measured: 2

## Formula / methodology
```
Total = Σ Lengthᵢ × Widthᵢ     Acres = Total ÷ 43,560
```

Every filled section contributes its length × width rectangle to the running total. Leave unused sections blank. An acre is exactly 43,560 square feet, so the acres row simply divides the total; handy when measuring lots rather than rooms.

## Assumptions & limitations
- Sections are true rectangles; L-shaped spaces should be split and entered section by section.
- Measurements are interior for floor areas or property-line for lots.
- Closets, bays and stair treads counted only if entered explicitly.

## How to use
1. **Measure each rectangle**; Record length and width in feet for every distinct area; rooms, wings, or sections of a lot.
2. **Fill one to three sections**; Unused optional fields stay blank; both values of a section are required when used.
3. **Read the total**; The primary result is combined square feet; check the acres row for property-sized measurements.

## Example
A 30×20 great room plus a 15×15 office totals 600 + 225 = 825 square feet; about 0.0189 acres of floor space.

Result for these inputs:

```
Total square footage: 825 square feet
```

## About this calculator
### Breaking irregular shapes down

Almost no real floor plan is one clean rectangle. The professional habit is decomposition: split the space into overlapping-free rectangles, measure each, and let the arithmetic sum them. Three sections cover the vast majority of homes and apartments.

### Square feet vs acres

Rooms live in square feet; land lives in acres. Because an acre spans 43,560 sq ft; bigger than four NHL rinks; the conversion row keeps a large lot measurement from feeling abstract.

### Where accuracy pays

Flooring orders, heating-load estimates and appraisals all key off this number. Measuring to the inch rather than rounding to the foot routinely swings totals by 2–3%; enough to leave pallets of laminate short.

## FAQs
### How do I measure an L-shaped room?

Split it into two rectangles where they meet, measure each fully, and enter them as separate sections.

### How many square feet is an acre?

Exactly 43,560. A football-field-sized lot of about half an acre holds roughly 21,780 sq ft.

### Should I include closets?

For flooring, yes; they take material too. Enter closets as their own small sections.

### Do I measure inside or outside walls?

Inside faces for flooring and painting; outside dimensions for property and appraisal figures.

## Related calculators
- [Concrete Calculator](https://codeasystem.com/calculators/construction/concrete-calculator/)
- [Paint Calculator](https://codeasystem.com/calculators/construction/paint-calculator/)
- [Area Unit Converter](https://codeasystem.com/calculators/conversion/area-unit-converter/)

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Last updated: 2026-08-23 · Version: 1.0.0 · [HTML version](https://codeasystem.com/calculators/construction/square-footage-calculator/)