Slabs • Patios • Driveways • Footings • Posts
Use this Concrete Calculator in North Dakota to estimate cubic feet, cubic yards, concrete bags and material cost for North Dakota-area slabs, patios, driveways, sidewalks, footings, posts and other concrete projects. Enter your actual dimensions and local material price for a project-specific estimate.
Estimate slabs and patios, continuous footings, round posts/columns, or convert known square footage into bags and ready-mix cost.
Enter finished dimensions for a patio, driveway panel, garage slab, sidewalk section or other rectangular concrete flatwork.
Verify manufacturer bag yield.
Thickened edges, footings, steps and other deeper concrete sections should be calculated separately.
Estimate a uniform continuous footing, grade beam or strip foundation.
Estimate concrete for cylindrical posts, piers and round columns.
Already know the square footage? Convert area and slab thickness into cubic yards, bag quantity and material cost.
The calculator works from geometry, so the first step is measuring the actual concrete dimensions. For a slab, patio or driveway panel, measure finished length and width and enter the planned slab thickness. For a footing, measure total continuous length and use the actual width and depth from the project design. For posts or piers, use the finished diameter and poured height/depth.
After calculating exact volume, compare it with an optional allowance. The allowance is not a mandatory North Dakota percentage—it simply gives you a larger planning quantity to compare against the mathematical volume.
Use finished concrete dimensions.
Slab, footing, round post or area.
Use the project-specific concrete thickness.
Enter an North Dakota-area supplier quote if desired.
Check permits, plans and field dimensions.
For most rectangular slabs, the concrete quantity formula is straightforward.
Cubic yards = cubic feet ÷ 27.
A 20 × 20 foot slab at 4 inches thick contains about 133.33 cubic feet, or approximately 4.94 cubic yards before an ordering allowance.
| Project | Example Size | Thickness | Approx. Concrete |
|---|---|---|---|
| Small Patio | 10 × 12 ft | 4 in | 1.48 yd³ |
| Patio / Slab | 12 × 20 ft | 4 in | 2.96 yd³ |
| Garage Floor | 20 × 20 ft | 4 in | 4.94 yd³ |
| Driveway Section | 20 × 30 ft | 5 in | 9.26 yd³ |
| Large Slab | 30 × 40 ft | 6 in | 22.22 yd³ |
These are geometric examples only. Actual thickness, reinforcement, base preparation and project design can differ.
Location-focused guidance without forcing a single local price.
Calculations use project dimensions rather than broad averages.
Compare bagged concrete for smaller pours.
Estimate cubic yards before requesting a supplier quote.
Slabs are among the most common concrete projects in Central North Dakota, including patios, garage floors, sheds, equipment pads and other flatwork. The slab calculator converts the surface footprint and thickness into concrete volume.
Do not use excavation depth as slab thickness. Excavation can also contain compacted base, drainage layers or other materials. Enter the actual concrete thickness shown on the project plan.
For a dedicated slab page, use the Concrete Slab Calculator. For floor-specific work, use the Concrete Floor Calculator.
For a rectangular patio, multiply length by width to get square footage, then multiply by slab thickness. Irregular patios can be divided into rectangles, circles or other simple shapes and calculated separately.
Use the Concrete Patio Calculator for circular and L-shaped patio geometry.
A driveway estimate should be based on the actual driveway footprint and the specified thickness. If different driveway sections have different thicknesses, calculate each section separately and add the cubic-yard quantities.
Permit, right-of-way and driveway-access requirements can vary by city, county and road authority. Check the local building or engineering department for the property before construction. For statewide building-code information, use the North Dakota Department of Commerce Building Codes page.
Continuous strip footings and grade beams are calculated from total length × width × depth. The calculator does not size a footing structurally. Soil conditions, loads, building type and code requirements can affect foundation design, so use dimensions from approved plans or qualified design guidance.
For more detail, use the Concrete Footing Calculator or Concrete Foundation Wall Calculator.
Round concrete posts and piers use the cylinder formula π × radius² × height. If the project includes an enlarged footing at the bottom, calculate that footing separately. For larger structural columns, use the Concrete Column Calculator.
Concrete prices can change by supplier, mix specification, delivery distance, order size and additional service charges. Rather than hard-coding a citywide price, the calculator lets you enter a current local quote per cubic yard.
For sealer quantities after the project is ready for treatment, use the Concrete Sealer Coverage Calculator.
This North Dakota concrete calculator can be used for quantity estimates in Fargo, Bismarck, Grand Forks, Minot, West Fargo, Dickinson, Williston, Mandan and rural projects across the state. The volume formulas are the same everywhere: measure the finished concrete geometry, convert thickness correctly and calculate cubic yards.
Local ready-mix prices, minimum loads, delivery zones, seasonal availability, permits and construction practices can differ. Enter your own supplier price in the calculator rather than relying on a statewide average.
North Dakota concrete projects often require careful cold-weather planning. Low air and concrete temperatures can slow early strength development, while freezing can damage fresh concrete if protection is inadequate. The geometric concrete quantity does not change because of temperature, but production, delivery, placement, curing and protection procedures can change significantly.
ACI cold-weather guidance defines cold-weather concreting around periods when air temperature is at or expected to fall below 40°F (5°C) during the protection period. Use the project specification and qualified construction guidance for heating, insulation, curing and protection decisions.
Technical reference: ACI PRC-306-16: Guide to Cold Weather Concreting. For curing scheduling, use the Concrete Cure Time Calculator.
North Dakota exterior concrete planning should account for drainage, base preparation and seasonal freeze-thaw conditions. The calculator estimates material volume only; it does not design drainage, frost protection, air entrainment, base thickness or reinforcement.
Before ordering ready-mix, verify the subgrade, compacted base, forms, reinforcement and access route. Uneven excavation or unplanned deeper areas can increase concrete volume even when the nominal slab dimensions have not changed.
Permit and inspection requirements can vary by city, county, project type and whether the work is structural. North Dakota maintains a state building code framework, while local jurisdictions can have their own administration and enforcement responsibilities.
For current statewide code information, use the official North Dakota Department of Commerce Building Codes page. For a specific slab, driveway, footing, foundation or structural project, also check with the local building official before construction.
The North Dakota Department of Commerce publishes the official state building-code information and adopted updates. The current North Dakota State Building Code took effect January 1, 2026, following adoption of the 2024 IBC, IRC, IMC and IFGC updates plus state amendments.
Local administration can still matter, so use the official North Dakota Building Codes page and check the local authority having jurisdiction for the exact project.
This page is a concrete material estimator, not a code-compliance or structural-design tool.
Small repairs and pads may be practical with bagged concrete, while larger slabs, patios and footings can require many bags. The calculator lets you compare approximate bag quantity with ready-mix cubic yards.
Bag yields vary by manufacturer and product. Verify the package yield before purchasing. For larger pours, ready-mix can simplify batching but may include delivery minimums, short-load fees or waiting-time charges.
The exact mathematical quantity assumes uniform thickness, perfect forms and zero placement loss. Real job sites can differ because of uneven base elevations, over-excavation, form tolerance or concrete left in placement equipment.
The calculator's allowance field is optional. Choose the final order based on actual field conditions and supplier guidance.
Concrete is volume, so thickness must be included.
The calculator expects slab thickness in inches and converts it automatically.
Calculate each thickness zone separately.
Add deeper concrete geometry separately.
Enter a current supplier quote instead of relying on an old citywide average.
Check official North Dakota permitting information for the exact project scope.
The calculator does not select slab thickness, footing size, reinforcement or concrete strength.
Public roadway, bridge and transportation concrete should follow the applicable contract plans and agency specifications rather than residential calculator assumptions. The North Dakota Department of Transportation Road and Bridge Construction Specifications page provides current agency resources for NDDOT work.
For ordinary private projects, use this calculator for quantity planning and rely on the project designer, local building official and supplier for technical requirements.
Concrete quantity comes from finished project dimensions. Weather affects placement and curing procedures, not the basic geometric volume.
Suppose a North Dakota residential slab is 12 feet by 20 feet and 4 inches thick. The area is 240 square feet, and the thickness is one-third of a foot.
With a 10% planning allowance, the calculator shows about 3.26 cubic yards.
Common questions about North Dakota concrete yards, slabs, patios, driveways, bags, cost and permits.