# dasaas

> dasaas (https://dasaas.com) is a collection of free online tools and calculators that run in the web browser. No sign-up or download. All da tools. All free.

Every calculator updates as you type, accepts feet-and-inches input such as 9' 4 1/2", keeps its inputs in the page URL so results can be shared, and shows drawings or 3D views of the result. Construction tools check results against the International Residential Code or National Electrical Code where relevant.

## Construction & DIY

Stairs, roofs, concrete, lumber and wiring, worked out with diagrams, 3D views and code checks.

- [Stair Calculator](https://dasaas.com/construction/stair-calculator/): Risers, treads and a stringer layout, checked against residential code.
- [Roof Pitch Calculator](https://dasaas.com/construction/roof-pitch-calculator/): Pitch, angle, rafter length and roofing squares for gable, hip and shed roofs.
- [Board Foot Calculator](https://dasaas.com/construction/board-foot-calculator/): Board feet and lumber cost for a whole list of boards.
- [Concrete Calculator](https://dasaas.com/construction/concrete-calculator/): Cubic yards and bags for slabs, footings and round columns.
- [Square Footage Calculator](https://dasaas.com/construction/square-footage-calculator/): Add up rooms and shapes in feet and inches, with cost per square foot.
- [Gravel Calculator](https://dasaas.com/construction/gravel-calculator/): Cubic yards, tons and bags of gravel, sand or soil for any area.
- [Mulch Calculator](https://dasaas.com/construction/mulch-calculator/): Cubic yards and bags of mulch for beds of any size and depth.
- [Voltage Drop Calculator](https://dasaas.com/construction/voltage-drop-calculator/): Voltage drop for copper and aluminum wire, and the smallest size under 3%.

## Facts the tools use

- Stairs (IRC 2021): risers at most 7 3/4 in (R311.7.5.1), treads at least 10 in (R311.7.5.2), width at least 36 in (R311.7.1), headroom at least 6 ft 8 in (R311.7.2), at most 151 in of rise per flight (R311.7.3).
- Number of risers = total rise ÷ 7.75 in, rounded up; treads = risers − 1. A 108 in rise needs 14 risers of 7 11/16 in.
- Roof pitch is rise per 12 in of run; angle = arctan(pitch ÷ 12). Pitch factor = √(1 + (pitch ÷ 12)²). A roofing square is 100 sq ft, usually 3 bundles of shingles.
- Asphalt shingles need at least a 2/12 pitch; 2/12 to 4/12 needs two layers of underlayment (IRC R905.2.2, R905.1.1).
- Board feet = thickness (in) × width (in) × length (ft) ÷ 12, using nominal sizes. A 2×4×8 is 5.33 board feet.
- Concrete: cubic yards = cubic feet ÷ 27. Typical bag yields: 80 lb = 0.60 cu ft, 60 lb = 0.45 cu ft, 40 lb = 0.30 cu ft, so one cubic yard is 45 bags of 80 lb.
- Gravel and mulch: cubic yards = area (sq ft) × depth (in) ÷ 324. Crushed stone weighs about 1.4 tons per cubic yard. One cubic yard of mulch covers 108 sq ft at 3 in deep.
- Voltage drop (single-phase) = 2 × amps × ohms per 1,000 ft × one-way feet ÷ 1,000; three-phase uses 1.732 instead of 2. Resistance from NEC Chapter 9, Table 8. NEC informational notes recommend at most 3% on a branch circuit and 5% in total.

## About

- [About dasaas](https://dasaas.com/about/): what the site is and how it works.
- [Privacy](https://dasaas.com/privacy/): calculations run in the browser; no accounts or cookies.

Tool results are estimates for planning. Local building codes and product specifications take precedence.