How big does a stair landing need to be?

IRC R311.7.6 requires minimum 36″ depth × full stair width. For a 36″ stair: 36″ × 36″ landing = 9 sqft minimum. Bigger is better — most builds use 48″ × 48″ (16 sqft) for usability. Above 60″ × 60″ is luxury/grand-entry territory.

What's the best material for a stair landing?

Concrete pad is most permanent + cheapest IRC-compliant option ($8.50/sqft installed). Pavers add aesthetic for ~$14/sqft. Gravel base ($3.20/sqft) works for budget DIY but settles over time. Deck extension ($22) is most expensive but seamless aesthetic — landing matches deck material exactly.

Do I need footings for a stair landing?

For concrete pad + pavers in any zone with frost (28+ states have measurable frost depth) — yes, below-frost footings prevent heave. IRC R403.1.4 mandates footings to frost depth. Gravel base + deck extension don't need separate footings (gravel floats; deck extension uses existing deck framing).

How much concrete for a 4x4 landing?

4×4 landing (16 sqft) with 4″ slab + 4 footings @ 36″ frost depth: slab volume = 5.33 cu ft. Footing volume = 4 × π × (7/12)² × 3 ft = 15 cu ft. Total = 20.3 cu ft = 0.75 cu yd. That's 22 bags of 80lb Quikrete OR 1 cu yd truck delivery ($150-200 typical, includes minimum charge).

Can I use pavers for a stair landing?

Yes — popular premium upgrade. Cost: $14/sqft installed (pavers + sand base + edge restraint). For a 4×4 landing = $224. Pavers offer aesthetic flexibility (color/pattern), drainage through joints, easy replacement if damaged. Requires 4-6″ compacted base + 1″ sand setting bed below pavers + perimeter edge restraint to prevent shifting.

What about gravel landing?

Budget DIY option ($3.20/sqft installed). 4-6″ depth of compacted #57 crushed stone over fabric. Works for: occasional-use deck stairs, dry climates, temporary builds. Doesn't work for: snow-region freeze-thaw (settles), high-traffic (compacts unevenly), bare feet (uncomfortable). Most cost-effective if you DIY + tolerate the look.

Should the landing match my deck?

If aesthetics matter + budget allows, yes — extend the deck framing one extra section as a floating 'deck landing' ($22/sqft includes framing + composite/PT decking). Same material + finish + color. Visually seamless. Pro: looks like the deck flows down. Con: 2-3× cost of concrete pad + requires more framing.

How deep should landing footings be?

Below frost depth per IRC R403.1.4. State frost depths range 0-60 inches: Gulf/Florida 0″ (no footings needed structurally), Mid-Atlantic 30-36″, Upper Midwest 48-60″. 14″ Ø sonotubes at frost depth × 4 corners is the standard. The Footing Depth Calculator gives state-specific values.

Can I skip footings if the landing is gravel?

Yes for floating gravel base — the gravel itself absorbs minor frost movement. But this only works for low-traffic occasional-use landings. For high-traffic decks where you walk down stairs daily, gravel settles unevenly + becomes annoying. Better: concrete pad + frost footings = $$400-600 one-time cost vs gravel ' redo-every-3-years problem.

Stair · IRC R311.7.6 landing

Stair Landing Calculator

IRC R311.7.6 landing sizing — minimum 36″ depth × full stair width. 4 materials: concrete pad ($8.50/sqft most permanent), pavers ($14 premium), gravel ($3.20 budget DIY), deck extension ($22 matches deck). Includes below-frost concrete footings + concrete cubic yards math for bag/truck planning.

IRC R311.7.64 materialsFootings included

36″·IRC min depth

4·Materials

ft²·Area + cost

cu yd·Concrete math

Inputs

Stair widthft (≥3 IRC)

Landing depthft (≥3 IRC)

Material

Frost depthstate-specific

Footings

Landing · concrete pad

9 sqft$457 · 0.59 cu yd concrete

Area

3×3

Material

concrete pad

Footings

@ 36″ frost

Total cost

0.59 cu yd concrete

IRC compliance + footings

9 sqft landing — IRC compliant

IRC R311.7.6

3ft × 3ft meets R311.7.6 minimum. Standard residential sizing.

4 below-frost footings @ 36″

IRC R403.1.4

4 corner footings to 36″ frost depth per IRC R403.1.4. $380.

IRC R311.7.6 landing + R403.1.4 frost-depth footings. Pair with Footing Depth + Stair Stringer + Concrete Bag Calculators for full build math.

How to use

How to use the deck calculator in 3 steps.

Enter stair width

Match stair width from Stair Stringer Calculator — typically 3 ft (36″) residential, 4 ft for wider stairs.

Enter landing depth

IRC R311.7.6 minimum 36″ (3 ft). Bigger is better for usability — 4-5 ft landings prevent the 'step right into the wall' feeling.

Pick landing material

Concrete pad (most common, $8.50/sqft installed). Pavers (premium, $14). Gravel (budget DIY, $3.20). Deck extension (matches deck, $22 — most expensive but seamless aesthetic).

Set frost depth + footings

Frost depth determines footing depth (IRC R403.1.4). Most cold zones require below-frost footings to prevent heave. Include footings unless you're using a floating gravel base.

How we calculate

How DeckMath calculates the result — IRC 2021 sources.

The Stair Landing Calculator sizes the bottom-of-stair landing per IRC R311.7.6 — minimum 36″ depth × full stair width. 4 materials compared: concrete pad ($8.50/sqft, most permanent), paver stone ($14, premium aesthetic), gravel base ($3.20, budget DIY), deck extension ($22, matches deck material). Includes below-frost concrete footings at corners. Computes total cost + concrete cubic yards for bag/truck planning.

IRC references

IRC R311.7.6 — Landing min 36″ depth × full stair width
IRC R403.1.4 — Footings below frost line

IRC 2021 R311.7.6 + R403.1.4. Material pricing 2026-Q1 retail.

Landing area

area = stair_width × landing_depth

3 ft × 3 ft = 9 sqft (minimum IRC compliant). 4 ft × 4 ft = 16 sqft (comfortable). 5 ft × 5 ft = 25 sqft (luxury entry).

Material cost

cost = area × $/sqft

9 sqft × $8.50/sqft concrete = $76 material. Pavers: $126. Gravel: $29. Deck extension: $198.

Footing cost

footings = corners × $95 × (frost_depth / 36″)

4 corner footings at standard 36″ frost = $380. 60″ frost depth = $633 footing cost (deeper sonotubes + more concrete).

Concrete volume

volume = slab_volume + footing_volumes

Slab = area × 4″/12. Footings = count × π × r² × depth. 9 sqft slab + 4 × 36″ footings = ~0.25 cu yd concrete (~12 bags Quikrete 80lb).

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Deck calculator questions, answered.

Deck Stair Calculator

Risers, treads, stringer hypotenuse, and BoM for any deck height — IRC 2021 R311.7 compliant with auto handrail + landing-pad sizing.

Footing Depth Calculator

Per-footing IRC R507.3 sizer: depth from frost + structural, diameter from soil bearing, rebar spec, concrete order. 5 soils × 4 footing types.

Concrete Bag Calculator

Bag-count optimizer for post holes, slabs, sonotubes, pier blocks. 15 SKUs across Quikrete + Sakrete + generic in 40-90 lb sizes. Pallet pricing tiers + mixer rental advisory + ready-mix breakpoint.