Concrete Sidewalk Calculator

How Big Is a Sidewalk Square?

A sidewalk square is normally as long as the walk is wide: 4x4 ft on a 4-foot residential walk and 5x5 ft on a 5-foot public sidewalk. The squares are simply the panels between control joints. Setting joint spacing equal to the walk width keeps each panel near-square, which is the shape least likely to crack down the middle, and it stays inside the 2-3x-thickness spacing rule for a 4-inch slab.

Replacing a single cracked square is a common repair: the per-square figures above are the pour only, so add removal of the old panel. Public sidewalks follow the Public Right-of-Way Accessibility Guidelines (PROWAG), which require a 4-foot minimum clear width (R302.3) and 5x5-ft passing spaces at least every 200 feet on walks narrower than 5 feet (R302.4) - one reason 5-foot walks with 5x5 squares are so common on city streets.

How Thick Is a Sidewalk?

A residential concrete sidewalk is 4 inches thick over 4 inches of compacted gravel, so the total excavation is about 8 inches. 3 inches is only acceptable for a light garden path; it gives up about 25% of the section that resists cracking and does not hold up to freeze-thaw as well. Any part of the walk that a car crosses - driveway aprons and curb cuts - is poured 6 inches thick. For the full breakdown by use and soil, see the sidewalk thickness guide.

Sidewalk Width and Thickness Standards

Sidewalk dimensions are driven by use, not guesswork. Residential walks run 36-48 inches wide; 48 inches lets two people pass comfortably. The ADA sets a 36-inch absolute minimum clear width, with 48 inches preferred, and caps cross-slope (side-to-side tilt) at 2% so the surface stays usable for wheelchairs. Running slope (along the path) should stay at or below 5% to avoid being classified as a ramp.

Thickness is simpler: 4 inches handles all foot traffic, wheelbarrows, and freeze-thaw. Step up to 6 inches only where vehicles cross the walk - driveway aprons and curb cuts - because the 4-inch section will crack under wheel loads.

Cost Per Square Foot vs. Per Linear Foot

Sidewalks are quoted two ways, and the gap between them confuses most homeowners. Installed plain flatwork runs $8-13 per square foot - higher than the $6-12/sq ft baseline for open slabs. The reason is geometry: a 4-foot-wide walk has form work on both long edges for every 4 square feet of surface, so the edge-and-finish labor per square foot is far higher than on a 20x20 patio. Narrower runs cost even more per square foot for the same reason.

Because width is roughly fixed, contractors often quote per linear foot instead. At 4 feet wide and $8-13/sq ft, that is about $32-52 per linear foot of finished walk.

Sidewalk Cost by Length and Size

The table below estimates installed cost for common residential runs at the standard 4-inch thickness. Read the low end as a broom finish in a low-cost region and the high end as decorative or freeze-thaw work in a high-cost metro.

Add $3-8/sq ft for stamped or colored finishes, and $2-4/sq ft if existing concrete must be demolished first. A 6-inch driveway-crossing section adds roughly $1-2/sq ft over the 4-inch price. For total-project numbers across other flatwork, use the Concrete Cost Calculator.

Concrete Volume and Mix

Volume scales directly with the surface area times thickness. A 30-foot residential walk (4 ft wide, 4 in thick) needs 1.48 cubic yards of concrete - about 67 bags of 80-lb mix before waste, or roughly 74 bags (1.63 cu yd) with 10% waste.

Specify a 3,500-4,000 PSI mix for exterior walks. In freeze-thaw climates use air-entrained concrete so water can expand without spalling the surface. Bagged mix is practical under about 1 cubic yard (roughly 20 linear feet at standard width); beyond that, ready-mix at $145-195 per cubic yard delivered is cheaper and faster. See the bagged vs. ready-mix comparison to decide.

Control Joints and Reinforcement

Shrinkage cracking is inevitable - control joints give the slab a planned place to crack cleanly. The rule of thumb is to space joints at no more than 2-3 times the slab thickness in inches, which for a 4-inch walk lands around 5 feet. A practical trick: set joint spacing roughly equal to the walk's width, so a 4-foot walk gets joints every 4 feet, forming near-square panels that resist lengthwise cracking.

Cut joints to one-quarter of the slab depth with a groover during finishing, or saw-cut within 6-18 hours of pouring. Plain residential walks usually do not need rebar; #3 or #4 bar or 6x6 wire mesh is added only at vehicle-crossing sections or over weak subgrade. Place a 1/2-inch foam expansion joint where the walk meets a house wall, steps, or existing concrete.

Base, Slope, and Permits

Compact 4 inches of gravel (3/4-inch crushed stone or road base) under the walk. Slope the finished surface 1/4 inch per foot - about 2% - away from structures for drainage, which also happens to match the ADA cross-slope ceiling.

Most detached residential walks on private property need no permit, but any sidewalk in the public right-of-way (between the curb and your property line) almost always requires a municipal permit and must meet local ADA detailing - permit fees typically run $50-200. Confirm before you pour; see our permit requirements guide.

DIY vs. Hiring a Pro

A short walk is one of the more DIY-friendly concrete projects. Under about 1 cubic yard (roughly a 20-foot run), bagged mix and a couple of helpers can save 50-60% on labor. Beyond that, ready-mix delivery and a finisher are worth it - long walks must be poured and finished within a single set window, and a poor slope or finish on a front walk is highly visible.

Hire a pro when the run exceeds ~30 feet, crosses a driveway, sits in the public right-of-way, or demands a decorative finish. For the full pour sequence, see How to Pour Concrete; to scope a wider paved area, switch to the Concrete Slab Calculator. Enter your walk's length, width, and thickness above to get an exact volume, bag count, and cost estimate in seconds.

Replacing a Sunken Sidewalk Square?

A sunken sidewalk slab can often be lifted instead of replaced: about $400–900 by mudjacking for 100 sq ft, although a single square usually costs the contractor's $300–700 minimum. For small runs, replacement is often close in price. See sunken sidewalk repair for trip-hazard limits and who pays, or compare both options in the concrete lifting cost calculator.