Continuous/Strip Footing Calculator — Volume, Rebar & Ties

Estimate concrete volume for continuous/strip footings and plan reinforcing. Enter width and depth once, then list one or more footing runs (lengths). Set waste, cover, bar sizes, laps (e.g., 40 db min 300 mm/12 in), stock length, and optional transverse ties (links). Get m³/yd³/ft³, bag counts, rebar lengths & weights, spacing counts, and a grouped cut list.

Units Metric (m, mm) US Customary (ft, in)

Inputs

Footing width (B)

Footing depth (D)

Number of runs

1–20

Add each straight segment length below.

Waste allowance

Covers spillage/variation (many jobs use 4–10%).

Footing runs

#	Length m

Rebar (longitudinal) — bottom & optional top

Concrete cover (to bars)

Typical footing cover is ≥75 mm (3 in) when cast against earth.

Bottom bars — count across width

bars

Enter number of continuous longitudinal bars at the bottom.

Bottom bar size

Top bars — count (optional)

bars

Set to 0 if not used. Top bars may be used at steps or special cases.

Top bar size

Stock bar length

Common stock ~6 m (20 ft); some carry 12 m (40 ft).

Lap splice settings (longitudinal)

Lap = × db Min: m

Default 40 db (min 300 mm / 12 in). Edit per your engineer/code.

End development (each end of run)

Extra length: m

Simple embed/anchor allowance; set to 0 if not required.

Transverse ties / links (optional)

Include ties

Tie bar size

Tie spacing along length

e.g., 300 mm (12 in) centers.

Tie hooks / bends

Hook each end: × db

Approximate additional length for bends (e.g., 10 db at each end).

Bag yields (optional display)

US bag yields (QUIKRETE® Concrete Mix)

40 lb:ft³ 50 lb:ft³ 60 lb:ft³ 80 lb:ft³

Edit to match your brand; defaults from common data sheets.

Metric bag yields

20 kg:m³ 25 kg:m³ 40 kg:m³

Results

Geometry & Concrete

Width × Depth: —

Total length: 0.000 m

Net volume: 0.000 m³

With waste: 0.000 m³

0.000 yd³ • 0.00 ft³

Bag counts (from total with waste)

40 lb: 0 • 50 lb: 0

60 lb: 0 • 80 lb: 0

20 kg: 0 • 25 kg: 0 • 40 kg: 0

Rebar (summary)

Longitudinal total: — • Weight: —

Ties total: — • Weight: —

Weights shown in your unit system (kg/lb).

Per-run volumes

#	Length	Volume

Rebar Totals

Longitudinal bars

Bottom bars across width: —

Top bars across width: —

Required per-run length (incl. end dev): —

Segments per run: 0 • Splices/run: 0

Transverse ties/links

Enabled: No

Ties count (all runs): 0

Length per tie: —

Cut List (grouped lengths)

Type	Bar size	Qty	Length	Note

Cut list assumes stock-length repeats plus a “remainder” per run. Laps are modeled as overlaps (extra steel).

How to use this footing calculator

Select metric or US units.
Enter footing width and depth once, then list each straight run length.
Set waste percentage for concrete ordering.
Enter cover, bar counts/sizes, stock length and laps. Add top bars if your detail requires.
Optional: enable ties/links, choose their size and spacing.
Read volumes, bag counts, rebar totals, and the grouped cut list. Round up for ordering.

Formulas & assumptions

Concrete volume (rectangular footing): V = B × D × ΣL.
Waste: V_w = V × (1 + waste%).
Longitudinal per-run length: L_req = L + 2×dev_end.
Lap splice: L_lap = max(lapDb × d_b, lapMin).
Segments per run (stock + laps): effective advance per additional segment = L_stock − L_lap. k = 1 if L_req ≤ L_stock, else k = ⌈(L_req − L_stock)/ (L_stock − L_lap)⌉ + 1. Splices/run = k − 1.
Total longitudinal steel (bottom + optional top): L_tot = (n_bot + n_top) × Σ( L_req + (k − 1)L_lap ) across runs.
Tie shape (rectangular): clear width = B − 2×cover, clear depth = D − 2×cover, base length ≈ 2×(clear B + clear D) + 2×hookDb×d_b. Count per run = ⌈L / s⌉ + 1.
Weights: Metric bars use kg/m ≈ d_mm² / 162; US bars use standard lb/ft table.
Scope: Estimator only—does not check bearing, shear, punching, or settlement. Follow your structural drawings and local code (e.g., ACI 318 or Eurocode 2).

References

Concrete cover for cast-in-place against earth: ≥3 in (≈75 mm). See ACI 318 “Cover for reinforcement”.
Typical bag yields: QUIKRETE® Concrete Mix 1101 data sheet (40/50/60/80 lb yields ~0.30/0.375/0.45/0.60 ft³).
Lap splices are development-length–based; common default is 40 db minimum 300 mm/12 in — verify per project specifications (ACI 318 / Eurocode 2).

FAQs

Does this handle stepped footings?

This version assumes constant width/depth along each straight run. For steps, enter separate runs per step or ask for a stepped-footing variant.

Do I need ties/links in strip footings?

Many straight strip footings use only longitudinal bars with minimal transverse steel; some engineers call for links at set spacing. Use your drawings/specs.

Does this account for dowels into walls/columns?

No—dowels are project-specific. You can add their length to the cut list manually, or we can add a dowel module if you like.