Plan Spokane Concrete Quantity Before You Order
Use this Concrete Calculator in Spokane, WA to estimate concrete for slabs, patios, driveways, sidewalks, footings, piers, walls and curbs. Calculate cubic yards, cubic feet, cubic meters, approximate concrete bags and optional ready-mix material cost before contacting a local supplier.
Choose the shape that best matches your project and enter actual finished dimensions.
Estimate concrete for rectangular patios, pads, floors and similar slab-on-ground projects.
Material estimate only. Verify thickness, reinforcement, base, joints, drainage, permits and structural requirements separately.
Estimate rectangular driveway, sidewalk, walkway or replacement-panel concrete.
If work touches the public right-of-way, verify Spokane permits, standard plans and inspection requirements before starting.
Choose a continuous rectangular footing or a round pier / post footing.
Volume only. Footing dimensions, reinforcement, soil bearing, structural design and structural compliance require project-specific design.
Estimate linear wall, stem wall, curb or similar rectangular concrete sections.
Material volume only. Verify wall, retaining, curb and right-of-way requirements before construction.
Convert project dimensions into the standard ready-mix ordering unit.
Approximate 40, 60 and 80 lb bag quantities for smaller Spokane projects.
Use a local supplier quote and plan truck access before placement day.
Check Spokane permits and standard plans when work affects regulated construction or public right-of-way.
A Concrete Calculator in Spokane helps homeowners, contractors, estimators and property managers turn project dimensions into a practical material quantity. Whether the work is a backyard patio, residential driveway, sidewalk replacement, garage slab, footing, pier, retaining-wall footing or curb section, the starting point is concrete volume.
This Spokane concrete calculator supports several common shapes because local projects are not all simple slabs. The Slab & Patio calculator handles rectangular flatwork. Driveway & Sidewalk is optimized for longer rectangular pours. Footing & Pier switches between a continuous footing and round pier geometry. Wall & Curb calculates long rectangular concrete sections.
The result shows exact mathematical volume and an adjusted planning quantity after the user-selected extra percentage. It also converts the order into cubic feet, cubic yards and cubic meters, estimates common bag quantities, and can multiply the cubic-yard quantity by a price entered from a local ready-mix quote.
The quantity depends entirely on finished dimensions and thickness. A concrete slab is calculated by multiplying length × width × thickness after putting every measurement into compatible units. Since ready-mix concrete in the United States is normally discussed in cubic yards, cubic feet are divided by 27.
Cubic yards = cubic feet ÷ 27.
A 20 ft × 12 ft patio that is 4 inches thick contains 80 cubic feet of concrete mathematically. That is about 2.96 cubic yards before any extra allowance. The calculator then applies the percentage you enter to create a planning order quantity.
Do not confuse square footage with concrete volume. Square feet describe surface area; concrete orders also require thickness. A 240-square-foot slab at 4 inches thick requires substantially less concrete than the same 240-square-foot slab at 6 inches thick.
Spokane concrete quantity planning can cover patios, garage slabs, driveway sections, sidewalks, equipment pads, footings, piers, foundation walls, retaining-wall footings, curb work, commercial site concrete and public-improvement projects. Projects range from private residential flatwork to infill construction, larger commercial development and transportation-related improvements, so the estimate should always use actual finished dimensions or approved project plans.
Concrete quantity is only one part of a compliant Spokane construction project. The City of Spokane Development Services Center reviews residential and commercial permits, plans and inspections, while Washington State establishes the statewide building-code framework.
The City's current residential and commercial code pages list the 2021 International Building Code, 2021 International Existing Building Code, 2021 International Residential Code, 2021 Washington State Energy Code, 2021 International Wildland-Urban Interface Code and 2021 Uniform Plumbing Code, with Spokane and Washington amendments as applicable. The Washington State Building Code Council made the 2021 code editions effective statewide on March 15, 2024.
Use the official Spokane Residential Codes, Spokane Commercial Codes, and Washington State Building Code Council pages to verify current requirements.
If concrete work affects a sidewalk, driveway approach, curb, street edge or another public-right-of-way feature, the cubic-yard estimate should be paired with Spokane Engineering standards and permit requirements.
Spokane Municipal Code requires sidewalks to be designed and constructed in accordance with the City's design standards, standard plans and specifications. In residential zones, the code requires a minimum five-foot sidewalk dimension and states that sidewalks within the public right-of-way are concrete with a two-foot grid, standard sidewalk color and float finish unless otherwise allowed.
The City also publishes a driveway-approach application and engineering standards governing driveway location and access. Work that obstructs or disturbs a public way is subject to obstruction-permit requirements under the Spokane Municipal Code.
Review the official Spokane Development Resources, Design Standards, and Standard Plans before beginning applicable right-of-way work.
For a basic rectangular patio, measure the finished length and width inside the forms and enter the planned thickness. If the patio is L-shaped, divide it into rectangles, calculate each section and add the volumes. If it contains a circular section, use the Round Concrete Slab Calculator.
Before placing concrete, verify grading and drainage. A material calculator cannot tell you where runoff should go or whether a patio elevation conflicts with doors, vents, weep screeds, property drainage or other building details.
For a pool-area project, use the Concrete Pool Deck Calculator. For a tapered transition, use the Concrete Wedge Calculator.
A driveway quantity estimate needs length, width and thickness. If the driveway changes width, calculate separate sections rather than using one rough dimension. Thickened edges, aprons, curb transitions or replacement panels should also be calculated separately if their geometry differs.
Do not use this page to select driveway thickness or reinforcing. Vehicle loading, base conditions, jointing, site drainage, project plans and public-works details can all matter. If the work reaches the city sidewalk, curb or street interface, confirm the applicable City of Spokane requirements before demolition or placement.
For joint planning after the dimensions are known, use the Concrete Joint Spacing Calculator and Concrete Saw Cut Calculator.
Continuous footings use rectangular volume. The calculator converts footing width and depth from inches into feet, multiplies them by length and then converts the result to cubic yards.
Round piers use cylinder geometry. Their volume equals π × radius² × depth × quantity. Enter the actual diameter and depth shown on the project design rather than choosing a size from the calculator.
Diameter must be divided by two to obtain radius.
For preliminary footing geometry calculations, use the Concrete Footing Size Calculator. For reinforcing placement, see the Concrete Cover Calculator and Concrete Rebar Spacing Calculator.
Spokane Development Services provides online permitting tools for building and development projects. City resource pages include guidance for getting started online, paying permit fees, printing permits and review comments, scheduling inspections and applying for certain trade or obstruction permits.
For concrete estimating, calculate from the latest approved geometry rather than an early concept sketch. Recalculate whenever slab thickness, footing width, wall geometry, driveway-approach dimensions, public-improvement details or grading changes during review.
The City's permit-activity map can also show recent building, planning and engineering permit activity, including street construction, obstruction permits and private-development right-of-way work.
Spokane Municipal Code prohibits obstruction of a public way except by permit, except for defined emergencies that must still be reported and permitted after the fact when required. The City's Development Resources page provides an Online Obstruction Permit guide and a separate Application for Driveway Approach.
Driveway approaches must comply with Spokane engineering standards. The Municipal Code requires driveway locations to avoid hazards to pedestrians and motorists and requires driveway access to connect to off-street parking on private property.
For work that cuts, blocks or otherwise occupies the public right-of-way, verify traffic-control, restoration and permit conditions before construction. Permit holders are responsible for restoring affected portions of the public way as required by the permit.
Use the official Spokane Development Resources and SMC 12.02.0706 – Permits Required for current guidance.
Spokane projects can involve freezing winter temperatures, frost-sensitive soils, snowmelt, sloped lots and drainage considerations. These conditions do not change the basic concrete-volume formula, but they can change footing depth, base preparation, retaining-wall geometry, slab elevation and drainage details.
The City's residential permit resources include a Frost Depth Joint Policy and separate handouts for slopes, setbacks and soils reports. Use approved structural and civil plans rather than generic dimensions when frost or site conditions control the design.
Recalculate concrete whenever footing depth, wall thickness, slab section or drainage geometry changes during review.
This Concrete Calculator in Spokane can be used for projects in Downtown Spokane, South Hill, North Spokane, West Central, East Central, Hillyard and other neighborhoods within City jurisdiction. The volume formula does not change by neighborhood, but site slope, access, frost conditions, soil, drainage, delivery distance and permit requirements can differ.
A Spokane mailing address does not always mean the property is inside City limits. The City's residential permit-process page specifically advises property owners to verify whether a site is within the City of Spokane or Spokane County before selecting the permit authority.
Use this page for quantity and ordering preparation, then match the estimate to the approved plans and the agency that has jurisdiction over the actual property.
Concrete prices are not hard-coded into this calculator because Spokane-area ready-mix rates, haul distance, minimum-load policies, fuel charges, mix specifications, waiting time, pumping and delivery conditions can change. Enter the price per cubic yard from a current local supplier quote to calculate a simple material estimate.
The resulting cost covers only the entered cubic-yard rate. It does not automatically include labor, reinforcement, forms, base material, demolition, haul-off, pumping, line-pump setup, short-load charges, permits, inspections, finishing or curing.
For delivery logistics, use the Concrete Delivery Distance Calculator. For placement duration, use the Concrete Pour Time Calculator.
Small repairs and pads may be practical with bagged concrete. Large patios, driveways and foundation pours can require many bags, which increases handling and mixer-cycle time. The calculator provides approximate counts for 40 lb, 60 lb and 80 lb bags using typical planning yields, but the actual bag yield printed by the manufacturer should control purchasing.
If a project needs many mixer batches, use the Concrete Mixer Size Calculator to compare mixer capacity and approximate batch count. For ready-mix work, coordinate delivery rate with your crew and placement method so concrete does not arrive faster than it can be handled.
Spokane concrete placement can involve hot, dry summer conditions, cold winter weather, wind and freeze-thaw exposure. Concrete planning should therefore use the actual project-date forecast rather than a seasonal average.
Use the Concrete Hot Weather Calculator during warm or dry placement conditions and the Concrete Cold Weather Calculator when low temperatures or freezing conditions are a concern. Actual placement, protection, finishing and curing procedures should follow the ready-mix supplier, approved project specifications and applicable professional guidance.
Concrete requires a thickness dimension. Square footage alone cannot determine cubic yards.
A 4-inch slab is 0.3333 foot thick, not 4 feet.
Turn-down edges, footings, curbs and thickened strips can add significant volume beyond the main slab.
Excavation and forming can change project dimensions. Calculate from final geometry before ordering when possible.
The volume estimate does not authorize construction or determine code compliance.
| Project | Dimensions | Exact Volume | Before Extra Allowance |
|---|---|---|---|
| Small Patio | 10 × 10 ft × 4 in | 33.33 ft³ | 1.23 yd³ |
| Patio | 20 × 12 ft × 4 in | 80.00 ft³ | 2.96 yd³ |
| Walkway | 40 × 4 ft × 4 in | 53.33 ft³ | 1.98 yd³ |
| Driveway Section | 30 × 12 ft × 5 in | 150.00 ft³ | 5.56 yd³ |
| Garage Slab | 20 × 20 ft × 4 in | 133.33 ft³ | 4.94 yd³ |
These examples are mathematical references only. Calculate your actual dimensions and project thickness.
The City of Spokane Development Services Center provides online permitting resources for building and development work. Residential and commercial permit-process pages explain application, plan-review and permit-status workflows, while registered contractors can use the online permit system for several permit and inspection functions.
The City's inspection pages state that all work for which a permit is issued requires at least one inspection and many projects require multiple inspections depending on scope. The permit applicant is responsible for requesting the required inspections and keeping work accessible and exposed until approval.
Before ordering concrete for permitted work, confirm whether a footing, foundation, reinforcing, slab or other pre-pour inspection is required. Use the latest approved dimensions so the concrete quantity matches the approved construction.
Official resources: Residential Permit Process, Commercial Permit Process, and Residential Inspections.
Spokane Engineering publishes standard engineering details, general notes, drainage criteria and private-development plan-review resources. The City's Civil Engineering Plan Submittal Process requires site-specific civil plans to include paving and City standard detail sheets where applicable.
The City states that work and materials must comply with Spokane Construction Standards and Specifications and NCTCOG Public Works Construction Standards, with Spokane standards taking precedence if the two publications conflict.
For a concrete estimate, this means the quantity should be calculated from the actual section required by the approved plan or City detail—not from a generic thickness assumption.
See the official Civil Engineering Plan Submittal Process and Standard Details and Resources.
The City of Spokane publishes current Standard Plans and updates them periodically. The City's standard-plan page says the versions posted online are the most current available and advises project teams to compare the date on any saved copy against the online version.
The current library includes Section F – Curbs and Sidewalks, Section D – Retaining Walls, Section W – Roads and Pavement, along with storm-drainage, water, sewer and other infrastructure sections. The page also lists recent update summaries, including a 2025 Standard Plans Update Summary.
These technical standards can change sidewalk depth, curb geometry, pavement section, retaining-wall details and other quantities. When a Spokane standard plan or approved civil drawing applies, calculate concrete from that required geometry rather than from a generic thickness assumption.
Official reference: City of Spokane Standard Plans.
Use the Concrete Volume Calculator for general geometry, the Round Concrete Slab Calculator for circular pads, and the Concrete Cubic Yard Calculator for direct yard conversions.
For reinforcing, see the Concrete Rebar Calculator, Concrete Rebar Spacing Calculator and Concrete Cover Calculator. For scheduling and logistics, use the Concrete Pour Time Calculator and Concrete Delivery Distance Calculator.
Measure final dimensions, convert them to volume, plan delivery access and verify City requirements where applicable.
Common questions about concrete yards, bags, local permits and Spokane project planning.