The numbers you look up most often, in one place: lumber sizes, wire gauges, pipe slopes, pitch multipliers and more.
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For reference only. These charts are general guides for planning and estimating. Codes vary by location and change over time, so check your local code before you build.
Real header sizes depend on the loads above them. Use your local code's tables, and a structural engineer for load-bearing work.
Electrical
Copper wire gauge and ampacity
AWG
60°C
75°C
Common use
14
15 A
20 A
Lighting and outlets
12
20 A
25 A
Kitchen, bath and garage
10
30 A
35 A
Dryers, A/C and water heaters
8
40 A
50 A
Ranges and large A/C
6
55 A
65 A
EV chargers and sub-panels
4
70 A
85 A
Large sub-panels
2
95 A
115 A
Sub-panels
1/0
125 A
150 A
Service entrance
2/0
145 A
175 A
Service entrance
3/0
165 A
200 A
200 A service
Circuit breaker sizes
Breaker
AWG
Typical load
15 A
14
Lighting and general outlets
20 A
12
Kitchen, bath and garage
30 A
10
Dryer, water heater and A/C
40 A
8
Electric range
50 A
6–8
Range or Level 2 EV charger
60 A
6
Hot tub or sub-panel feed
100 A
1–2
Small sub-panels
200 A
2/0–3/0
Main residential service
Typical device heights above the floor
Device
Height
Duplex outlet
12" to 18"
Kitchen counter outlet
44" to 48"
Switch or dimmer
48"
Thermostat
48" to 60"
Panel, top breaker
6' 7" maximum (NEC)
Adjust for conduit fill, and for ambient temperatures above 86°F. Follow the NEC and your local code, which decide what you can actually install.
Plumbing & HVAC
Common pipe sizes
Size
Material
Use
1/2"
Copper / PEX
Branch supply lines
3/4"
Copper / PEX
Main supply runs
1"
Copper / PEX
Main service entry
1 1/4"
PVC / ABS
Lavatory drains and P-traps
1 1/2"
PVC / ABS
Sink drains and washers
2"
PVC / ABS
Shower drains and vents
3"
PVC / ABS
Toilets and branch drains
4"
PVC / ABS
Main drain and sewer
Drain slope
Pipe size
Minimum slope
2 1/2" and smaller
1/4" per foot
3" and larger
1/8" per foot
Drain fixture units
Fixture
DFU
Bathtub or shower
2
Toilet
3–4
Lavatory
1
Kitchen sink
2
Dishwasher
2
Clothes washer
3
Floor drain
2
HVAC BTU rule of thumb
Climate
BTU per sq ft
Hot and humid
20–25
Mixed
25–30
Cold
30–35
Very cold
35–40
1 ton of cooling is 12,000 BTU per hour. This is only a rough guide, and proper sizing needs a Manual J load calculation. Slopes and fixture units are general references, so check the plumbing code that applies to you.
Roofing
Pitch chart
Pitch
Degrees
Multiplier
2:12
9.5°
1.014
3:12
14°
1.031
4:12
18.4°
1.054
5:12
22.6°
1.083
6:12
26.6°
1.118
7:12
30.3°
1.158
8:12
33.7°
1.202
9:12
36.9°
1.250
10:12
39.8°
1.302
12:12
45°
1.414
Material coverage
Material
Coverage
1 square
100 sq ft
3-tab or architectural shingles
About 3 bundles per square
Ridge cap
About 25 to 35 linear ft per bundle
Ice and water shield
About 200 sq ft per roll, but sizes vary
15 lb felt
About 400 sq ft per roll
30 lb felt
About 200 sq ft per roll
Nailing
Situation
Nails per shingle
Standard
4
High wind or steep slope
6
Follow the shingle maker's instructions and local code, because nailing affects the warranty. For a takeoff, use the roofing calculator.
Painting & finishing
Paint coverage per gallon
Product
Coverage
Flat / matte
350–400 sq ft
Eggshell / satin
300–350 sq ft
Semi-gloss / gloss
250–300 sq ft
Primer
250–400 sq ft
Exterior paint
250–300 sq ft
Solid stain
150–250 sq ft
Semi-transparent stain
200–300 sq ft
Sheen guide
Sheen
Best for
Flat / matte
Ceilings and low-traffic walls
Eggshell
Living rooms and bedrooms
Satin
Hallways and kitchens
Semi-gloss
Trim, doors and bathrooms
Gloss
Cabinets and trim accents
Concrete & masonry
Mix strengths
PSI
Typical use
2,500
Residential footings
3,000
Slabs, driveways and sidewalks
3,500
Traffic slabs and garage floors
4,000
High-strength and structural
5,000+
Commercial and high-load
Bag coverage
Bag
Yield
At 4" thick
At 6" thick
60 lb
0.45 ft³
1.35 sq ft
0.9 sq ft
80 lb
0.60 ft³
1.8 sq ft
1.2 sq ft
CMU block sizes
Nominal
Actual
4" CMU
3 5/8" × 7 5/8" × 15 5/8"
6" CMU
5 5/8" × 7 5/8" × 15 5/8"
8" CMU
7 5/8" × 7 5/8" × 15 5/8"
12" CMU
11 5/8" × 7 5/8" × 15 5/8"
Cure times
Time
Strength
Notes
24–48 hours
About 25–40%
Careful foot traffic
7 days
About 65–70%
Light vehicle traffic
28 days
100%
Full design strength
Cure times vary with the mix and the weather. For quantities, use the concrete calculator.
Drywall
Sheet sizes
Size
Thickness
Use
4×8
3/8"
Curved walls and patches
4×8
1/2"
Standard walls and ceilings
4×12
1/2"
Fewer seams on long walls
4×8
5/8"
Ceilings at 24" on center
4×8
5/8" Type X
Fire-rated assemblies and garages
4×8
1/2" moisture-resistant
Damp areas, but not behind tile in wet zones
Screw spacing
Location
Framing
Spacing
Walls
16" on center
16" field, 8" edges
Walls
24" on center
12" field, 8" edges
Ceilings
16" on center
12" field, 8" edges
Ceilings
24" on center
12" field, 8" edges
Requirements vary by board and code, so follow the manufacturer's instructions. For quantities, use the drywall calculator.
Flooring
Tile grout joint width
Tile size
Joint
1" to 3" mosaic
1/8"
4×4 to 6×6
1/8" to 3/16"
12×12 to 18×18
3/16" to 1/4"
20×20 and larger
1/4" to 3/8"
Rectified, any size
1/8" minimum
Waste factors and underlayment are on the flooring calculator page. Follow the tile maker's recommended joint.
1 1/2" by 3 1/2". Lumber is named by its rough size before it's dried and planed.
12 AWG copper is the usual choice for a 20 A breaker. Long runs, conduit fill and high temperatures can change that, so follow the NEC and your local code.
1/4" per foot is the usual minimum for pipes 2 1/2" and smaller, and 1/8" per foot for 3" and larger. Check your local plumbing code.