PH Construction Calculator

🧱

CHB / Masonry

Blocks, mortar, cement, sand

🏗️

Concrete Mix

Cement, sand, gravel per cu.m.

⚙️

Rebar

Grade, weight, pieces (PNS 49)

🔗

Rebar Splicing

Lap length (NSCP 2015)

🟦

Slab Type

One-way vs two-way (L2÷L1)

🪣

Plastering

Cement & sand for wall plaster

🪜

Stair / Ramp

PD 1096 & BP344 compliant

🎨

Paint

Coverage, coats, gallons needed

🔲

Tile / Flooring

Tiles, adhesive, grout

🪵

Board Feet

Lumber computation

⛏️

Excavation

Earthworks, backfill, hauling

🏠

Roofing

Sheets, purlins, screws

📐

Unit Converter

Construction conversions

📚

References

Standards & formulas used

🧱 CHB / Masonry Estimator

Compute CHB pieces, mortar, cement & sand per wall

Please fill in Wall Length and Wall Height.

CHB Size

Wall Length (m) *

Wall Height (m) *

Opening Deductions

No. of Doors

Door Size (sq.m.)

No. of Windows

Window Size (sq.m.)

Wall Reinforcement (Fajardo)

Include Reinforcement?

Waste Factor (%)

CHB (₱/pc)

Cement (₱/bag)

Sand (₱/cu.m.)

Rebar (₱/kg)

Tie Wire (₱/kg)

CHB 12.5 pcs/sq.m.: Fajardo Table 1-7. Mortar (4″: 0.25 bag + 0.015 cu.m. | 6″: 0.30 bag + 0.018 cu.m. per sq.m.): typical practice values — verify vs your Fajardo edition.
Standard door: 0.90×2.10m = 1.89 sq.m. | Window: 1.20×1.20m = 1.44 sq.m.

🏗️ Concrete Mix Estimator

Cement, sand & gravel per volume of concrete

Please fill in the Volume of Concrete.

Concrete Class / Mix Ratio

Compute Volume From

Volume of Concrete (cu.m.) *

Cement Bag Size

Waste Factor (%)

Cement (₱/bag)

Sand (₱/cu.m.)

Gravel (₱/cu.m.)

Ref: Fajardo Table 1-3 (Concrete Proportions). Sand 0.50 & gravel 1.0 cu.m. per cu.m. for all classes.

⚙️ Rebar Calculator

PNS 49:2020 — grade, weight, pieces & cost

Please fill in the required fields.

Bar Diameter

Grade (PNS / ASTM)

Compute By

Total Length Needed (m) *

Commercial Bar Length

Waste / Lap (%)

Price Basis

Price (₱)

Ref: PNS 49:2020 nominal mass. Unit weight is by diameter (same for all grades). Grade = yield strength (fy). Standard lengths: 6.0–12.0 m.

🪣 Plastering Estimator

Cement & sand for interior/exterior wall plastering

Please fill in Wall Length and Wall Height.

Wall Length (m) *

Wall Height (m) *

Plaster Thickness

Sides to Plaster

Mix Ratio

Opening Deductions

No. of Doors

Door Size (sq.m.)

No. of Windows

Window Size (sq.m.)

Waste Factor (%)

Cement (₱/bag)

Sand (₱/cu.m.)

Ref: Fajardo Plastering (Area Method). Sand = area × thickness; cement = (36 ÷ ratio) bags per cu.m. of sand. Check: @16mm, 1:4 → 0.144 bags + 0.016 cu.m. per sq.m. — matches Fajardo's table.

🪜 Stair / Ramp Calculator

PD 1096 Rule VII & VIII, BP344

Please fill in the required fields.

Calculate

Floor-to-Floor Height (m) *

Riser Height (mm) *

Tread Depth (mm) *

Stair Width (m)

Ref: PD 1096 Rule VII (Stairs), BP344 (Accessibility/Ramps)

🎨 Paint Estimator

Compute gallons needed for walls & ceilings

Please fill in Surface Area.

Surface Area (sq.m.) *

Number of Coats

Paint Type

Deduct Openings (doors/windows sq.m.)

Paint (₱/gallon)

Coverage based on typical Philippine paint brands. 1 gallon ≈ 3.785 L.

🔲 Tile / Flooring Estimator

Number of tiles, adhesive & grout needed

Please fill in Floor/Wall Area.

Floor/Wall Area (sq.m.) *

Tile Size

Waste Factor (%)

Tile (₱/pc)

Adhesive (₱/25kg bag)

Grout (₱/2kg pack)

Adhesive ~5 kg/sq.m. (25kg bags). Grout varies by tile size & joint width.

🪵 Board Feet Calculator

Lumber computation — board feet & total cost

Please fill in Thickness, Width, and Length.

Thickness (inches) *

Width (inches) *

Length (feet) *

No. of Pieces

Price per Board Foot (₱)

BF = (T″ × W″ × L′) ÷ 12 — standard board feet formula

📐 Unit Converter

Construction-specific unit conversions

From

Value

⛏️ Excavation & Earthworks

Excavation volume, backfill, spoils & hauling

Please fill in the required fields.

Compute Volume From

Length (m) *

Width (m) *

Depth (m) *

Soil Type (swell)

Truck Capacity (cu.m.)

Structure Volume Below Grade (cu.m.) — footing, slab, etc. Stays in the hole; excess soil gets hauled out.

Hauling (₱/truckload)

Swell factors: typical earthwork values (bank → loose). Backfill assumes excavated soil returned & compacted ≈ bank volume. Verify soil class on site.

🏠 Roofing Estimator

G.I. sheets, purlins & tek screws

Please fill in the required fields.

Roof Type

Sheet Type

Ridge Length (m) *

Plan Width, eave-to-eave (m) *

Pitch (degrees) *

Purlin Spacing (m)

Rib-type (₱/linear m)

Tek Screws (₱/pc)

C-Purlin (₱/6m pc)

Effective coverage: rib-type ≈ 1.00m, corrugated ≈ 0.70m (1½ corrugation side lap), 0.25m end lap. Screws ≈ 4 per m width per purlin line. Verify with your supplier's actual profile.

🔗 Rebar Splicing Calculator

Lap splice length — NSCP 2015 Sec. 425

Please fill in the required fields.

Bar Diameter

Steel Grade (fy)

Concrete Strength f'c

Splice Type

Bar Position

Cover & Spacing per Code?

Ref: NSCP 2015 Sec. 425.4.2 (development), 425.5.2 (tension lap A=1.0ld / B=1.3ld), 425.5.5 (compression lap). Normal-weight concrete, uncoated bars. Estimate only — always follow the lap lengths on your sealed structural plans.

🟦 Slab Type Calculator

One-way vs two-way slab by span ratio

Please fill in both span lengths.

Short Span L1 (m) *

Long Span L2 (m) *

One-way: slab bends mainly along the short span — main bars one direction. Two-way: bends in both directions — main bars both ways. Final slab thickness & reinforcement are the structural engineer's design.

📚 References & Standards

Sources behind every formula in this app

Fajardo — Simplified Construction Estimate

Max B. Fajardo Jr., 3rd Edition. Source for CHB & mortar (Table 1-7), concrete proportions (Table 1-3), and plastering works. The standard estimating reference in Philippine practice.

PNS 49:2020

Philippine National Standard for steel bars for concrete reinforcement. Defines grades (230/280/420/520 MPa ≈ ASTM 33/40/60/75), nominal mass per metre, sizes (8–50mm), standard lengths (6.0–12.0 m) and ±6% mass tolerance.

NSCP 2015

National Structural Code of the Philippines (ASEP). Governs structural design — concrete classes, reinforcement, development & lap lengths. Always size structural members per a licensed engineer's design.

NSCP 2015 — lap splices (Sec. 425)

Tension development ld (simplified, 425.4.2.3): db ≤ 20mm → ld = fy·ψt ⁄ (2.1λ√f'c) × db; db > 20mm → ÷1.7 (cover/spacing met) or ÷1.4 / ÷1.1 otherwise. ψt = 1.3 top bars. Tension lap: Class A = 1.0 ld, Class B = 1.3 ld, min 300mm. Compression lap: 0.071·fy·db (fy ≤ 420), ×1⅓ if f'c < 21 MPa, min 300mm.

Slab type rule (NSCP / ACI practice)

Span ratio L2 ÷ L1 ≥ 2 → one-way slab (bends along short span). Ratio < 2 → two-way slab (bends both directions). Screening rule for analysis method — final design by the structural engineer.

PD 1096

National Building Code of the Philippines. Rule VII / VIII — stair geometry: max riser 200mm, min tread 250mm, comfort rule R+T ≈ 430–460mm.

BP 344

Accessibility Law. Ramp design: max slope 1:12, min width 1.20m, level landings every 6.0m of run.

Steel unit weight formula

kg/m = D² ⁄ 162 (D in mm). Matches PNS 49 nominal mass. Used as fallback for any size not in the standard table.

CHB wall reinforcement (Fajardo)

Bar length per sq.m. of wall — vertical: 2.93 (@0.40m), 2.13 (@0.60m), 1.60 (@0.80m); horizontal: 3.30 (every 2 layers), 2.15 (every 3), 1.72 (every 4). Tie wire: #16 G.I., 1 roll = 45 kg ≈ 53 m/kg, est. 0.40m per intersection.

Earthwork swell factors

Typical bank→loose bulking: sand/gravel +12%, common earth +25%, clay +32%, blasted rock +50%. Compacted backfill assumed ≈ bank volume. Always confirm soil classification on site.

Roofing coverage (typical PH profiles)

Rib-type long span ≈ 1.00m effective width, cut to slope length. Corrugated G.I. ≈ 0.70m effective (1½ corrugation side lap), 0.25m end lap. Slope area = plan area ÷ cos(pitch). Profiles vary by manufacturer — verify with your supplier.

This app gives quantity estimates to speed up take-offs. It does not replace structural design, detailed engineering, or your approved plans.