Kalkulačka Betonových Schodů – Objem, Pytle a Odhad Nákladů
Calculate exactly how much concrete you need for a staircase project. Enter your stair dimensions to get the total concrete volume in cubic feet, cubic yards, cubic meters, number of bags, and an estimated material cost.
Jak používat tuto kalkulačku
- Zadejte Number of Steps
- Zadejte Step Width (inches)
- Zadejte Riser Height (inches)
- Zadejte Tread Depth (inches)
- Zadejte Landing/Platform Depth (inches, 0 if none)
- Klikněte na tlačítko Vypočítat
- Přečtěte si výsledek zobrazený pod kalkulačkou
How to Calculate Concrete for Stairs
Concrete stairs consist of a series of triangular prisms (when viewed from the side). Each step adds a right triangle cross-section. The formula for a single step's volume is:
Single step volume = (0.5 × riser × tread × width) × number of steps
But for a staircase, the cumulative volume is: each step includes its own tread/riser PLUS the solid base underneath previous steps. The total volume is calculated as:
Total volume = width × riser × tread × [1 + 2 + 3 + ... + n] / 12³
Where n = number of steps. This accounts for the triangular staircase cross-section, which is a right triangle with base = (n × tread) and height = (n × riser).
Standard Stair Dimensions
| Dimension | Residential | Commercial | Outdoor |
|---|---|---|---|
| Riser height | 7–7.75 in | 4–7 in | 5–7 in |
| Tread depth | 10–11 in | 11–12 in | 12–15 in |
| Stair width | 36 in min | 44 in min | 36–60 in |
| Headroom | 6 ft 8 in min | 7 ft min | N/A |
The "7-11 rule" is a common guideline: riser = 7 inches, tread = 11 inches. Another rule: 2 × riser + tread = 25–26 inches for comfortable climbing.
How Much Does Concrete Cost?
Concrete for stairs can be purchased as:
- Ready-mix (truck delivered): $120–$200 per cubic yard. Minimum order: usually 1 cubic yard. Best for larger projects.
- 80-lb bags: 0.6 cubic feet per bag = ~45 bags per cubic yard. ~$7–$10 per bag at hardware stores. Best for small projects (under 1/4 cubic yard).
- 60-lb bags: 0.45 cubic feet per bag = ~60 bags per cubic yard. ~$5–$8 per bag.
Labor cost to form and pour concrete stairs: $30–$60 per linear foot, or $200–$400 per step for contractor work including materials.
Concrete Mix for Stairs
Outdoor concrete stairs need a stronger, more durable mix than standard slabs:
- Minimum strength: 3,000 PSI. Outdoor stairs in freeze-thaw climates: 4,000 PSI
- Water-cement ratio: Keep below 0.45 for freeze-thaw resistance
- Air entrainment: 5–7% air entrainment is essential for freeze-thaw climates
- Fiber reinforcement: Polypropylene fibers reduce cracking
- Rebar: Use #3 or #4 rebar at 12-18 inch spacing for stairs over 4 feet wide
Bagged concrete mixes labeled "4000 PSI" or "High Strength" (like Quikrete 5000 or Sakrete High Strength) are appropriate for stairs.
Building Codes and Stair Requirements
Before building concrete stairs, check local building codes. International Residential Code (IRC) requirements:
- Maximum riser height: 7-3/4 inches
- Minimum tread depth: 10 inches
- Minimum width: 36 inches (residential interior)
- Handrail required: when 4 or more risers
- Consistent rise/run: largest riser can't exceed smallest by more than 3/8 inch
Permits may be required for exterior stairs attached to a structure. Check with your local building department before starting.
Tips for Pouring Concrete Stairs
- Build solid forms: Stairs require sturdy form work to contain the heavy concrete. Use 3/4-inch plywood with 2×4 bracing.
- Compact the base: Remove loose soil and compact gravel base to 4 inches minimum. Poor base = cracked stairs.
- Wet the forms: Wet wood forms before pouring to prevent absorption of water from concrete.
- Work quickly: Concrete has a 30–60 minute working time. Have helpers ready.
- Broom finish: Immediately after finishing, drag a broom across treads perpendicular to the front edge to create slip-resistant texture.
- Cure properly: Keep concrete moist for 7 days. Use curing compound or cover with plastic sheeting.
Reinforcement Planning
For structural integrity, concrete stairs should be reinforced with rebar:
- Rebar size: #3 (3/8") or #4 (1/2")
- Place rebar 1.5–2" from the bottom surface of each tread
- Extend rebar into the supporting wall or foundation 12–18 inches
- Tie horizontal and vertical rebar together with wire ties
For a 4-foot wide staircase with 5 steps, estimate 2–3 pieces of rebar per step plus 2 horizontal pieces. Total rebar: approximately 30–40 linear feet for this example.
Naposledy aktualizováno: March 2026
Frequently Asked Questions
How many bags of concrete do I need for 3 steps?
For 3 standard steps (48" wide, 7" riser, 11" tread): approximately 0.35–0.45 cubic yards = 20–27 80-lb bags. This varies with landing size and slab thickness. Always add 10% for waste.
What concrete mix is best for outdoor stairs?
Use at least 4,000 PSI concrete with air entrainment (5–7%) for outdoor stairs subject to freezing. Quikrete 5000 or Sakrete High Strength are good bagged options. For large pours, order air-entrained ready-mix from a concrete supplier.
How thick should concrete stairs be?
Concrete stairs should be at least 3.5–4 inches thick for residential applications. The solid base under the stairs (the triangular prism) is effectively much thicker, providing structural support. Thinner sections at the tread nose should still be 3+ inches.
Can I pour concrete stairs over existing concrete?
Yes, with proper preparation: clean the existing surface thoroughly, use a concrete bonding adhesive, roughen the surface with a grinder or acid etch, and ensure the new overlay is at least 1.5–2 inches thick. For stairs over 3 inches, use fiber-reinforced or polymer-modified concrete.
How long does concrete take to cure for stairs?
Concrete reaches 70% of its strength in 7 days and ~95% in 28 days at standard temperatures. You can walk on concrete stairs after 24–48 hours in warm weather. Avoid heavy loads for at least 7 days. Don't allow freezing temperatures in the first 48 hours.
Do concrete stairs need expansion joints?
If stairs are attached to a structure (house foundation), include an expansion joint (1/4–1/2 inch) where they meet the structure. This allows independent movement and prevents cracking. Fill with expansion joint material or self-leveling sealant.
What is the minimum slope for concrete stairs drainage?
Outdoor concrete stairs should have a slight slope of 1/8–1/4 inch per foot toward the front (nose) of each tread to shed water. Flat or back-sloping treads collect water and accelerate freeze-thaw damage.
How do I prevent concrete stairs from cracking?
Use proper mix design (low water ratio, air entrainment), compact the base thoroughly, use control joints every 4–6 feet in adjacent slab work, cure properly (7 days moist), reinforce with rebar or fiber, and seal annually with penetrating concrete sealer.
What is the cost to build 5 concrete steps?
DIY cost: $200–$500 for materials (concrete, forms, rebar). Contractor-built: $1,000–$2,500 for 5 basic steps including labor and materials. Adding railings, special finishes, or difficult access increases costs significantly.
How far should concrete stairs extend from a door?
Each step should extend the full width of the door opening plus 12–18 inches on each side (for safety). Tread depth accumulates with each step: 5 steps at 11" tread = 55" from door threshold plus any landing depth.