Lay out boards, posts and spacing

Decks & fences calculators

Deck and fence calculators convert overall dimensions into a preliminary material takeoff. Board width, spacing, run direction and stock length affect deck counts; fence length, panel width, corner locations and gate openings affect posts and panels. The results help compare materials and build a shopping list, but footing size, post depth, railing design, spans and structural connections must follow local codes and manufacturer requirements.

4 working calculatorsUS customary unitsReviewed July 23, 2026

Choose the calculation you need

Start with the material or decision in front of you.

Each tool performs a different takeoff or conversion. Open the closest match, enter real measurements, then review the stated assumptions before using the result to buy material.

deck calculator

Deck Project

Calculate deck square footage and a transparent planning budget from local decking, framing, railing, labor, and contingency rates.

Open calculator deck board calculator

Deck Boards

Estimate deck-board rows, fixed-length pieces, purchased boards, and surface coverage from board width, gap, span, and waste.

Open calculator fence calculator

Fence Materials

Estimate fence sections, posts, rails, and pickets from total run, gate openings, post spacing, rail count, picket width, gap, and waste.

Open calculator fence post calculator

Fence Posts

Calculate posts for equal fence runs and estimate concrete bags from hole diameter, depth, square post width, product yield, and waste.

Open calculator

How should you use a project calculator?

Begin with finished dimensions from the actual project area, not a plan that may have changed. Break irregular spaces into simple rectangles, triangles or individual runs and calculate each one separately. Keep units consistent, and measure openings, transitions and obstructions that materially change quantity.

The calculator result is a planning takeoff. Suppliers may sell only whole bags, boxes, panels or stock lengths, so purchase quantities are rounded up. Product-specific coverage, local codes, installation methods and site conditions remain the final authority.

Why does the waste allowance matter?

Waste covers cuts, breakage, unusable offcuts, settlement and measurement variation. A simple rectangular project may need only 5% extra, while diagonal layouts, complex roofs, patterned tile and many corners can require 10–15% or more. The right allowance depends on the material and layout, not a universal rule.

Keep unopened returnable packages separate when a retailer permits returns. For batch-sensitive finishes such as tile, flooring or brick, retaining a small matching surplus can also make future repairs easier.