Common Estimating Conversions and Formulas

math

The only estimating calculator you’ll need is already built in.

When 1build hears from the incredible contractors we work with each day, there are a few topics that always come up about how 1build can helped their businesses grow. First is winning more projects. The second is a good resource for those estimating formulas that turn a handful of measurements into a professional estimate. So, rather than switching between your estimating calculator and your bid sheet, 1build made it possible to enter these common conversions and formulas directly into your estimate line item. Then we pull from the latest local cost data for material, labor, and equipment, and you are done estimating before your superintendent turns in for the night.

Below we’ve included specific formulas for trades like framing, demolition, and drywall. We also included all the unit of measure conversions you’ll need to take your 2-D drawings into real life.

Even professional estimators learn one formula at a time. Here we go!

Wood Framing

TypeCalculation
Horizontal Studs: By CountCount of Horizontal Studs = (Wall Height in Linear Foot / Horizontal Stud Spacing)
Horizontal Studs: By Linear FootTotal LF of Studs = Stud Count * Stud Length + [WASTE(Total LF of Stud *Waste%)]
Vertical Studs: By CountCount of Vertical Studs = (Wall Length / Vertical Stud Spacing)
Vertical Studs: By Linear FootTotal LF of Studs = Stud Count * Stud Length + [WASTE(Total LF of Stud *Waste%)]

Metal Framing

TypeCalculation
Horizontal Studs: By CountLinear Foot of Wall * (Height of wall / Spacing of horizontal suds) / Stud Length = Stud Count
Horizontal Studs: By Linear FootStud length * Stud count = Total Linear Foot
Opening Framing Perimeter of opening in Linear Feet * 2 = Total Linear Feet of Framing Material
Vertical Studs: By CountLinear Foot of Wall / Spacing of suds in feet = Stud Count
Vertical Studs: By Linear FootStud count * Wall Height = Total Linear feet of Vertical Studs
Top and Bottom Plates(Linear Foot of Walls * Number of Studs Spec’d to support vertical studs at Ceiling) + (Linear Foot of Walls * Number of Studs Spec’d to support vertical studs at Floor)

Demolition

TypeCalculation
Dumpsters in WeeksWeekly infrastructure to support dumpsters consists of fencing, pads, operable roads and gates
Protection of Existing Finishes to RemainExisting Finishes = any undemolished item that shares a surface with a demolished item
Protection of Existing LandscapeExisting Landscape= any undemolished part of the landscape that shares a surface or path with a demolished item
Hazardous Materials TestingTesting = days of third party labor + fees for schedule slow downs (remobilization fees) + PPE / gear
Hazardous Materials RemovalRemoval = Labor to remove + hazard pay + Hazard PPE + On-site CDC/ Chemical reps + demobilization and testing of hired crews
Hazardous Materials: Crew Protection Protection = Proper site conditions, ventilation, power, sanitation stations, spacing and PPE replacement.
Heavy Demolition EquipmentEquipment Cost + Labor to Operate + Flat fees to rent + Insurance + infrastructure to support equipment

Concrete

TypeCalculation
Walls in CY of ConcreteVolume of Concrete = Linear Foot of Wall * Height of Wall * Thickness in Feet
Walls in Concrete Blocks Total Volume of Concrete in Wall / Block Volume (by specified size) = Approximate count of Blocks + Waste (in %)
Wood Forming: At Above Ground Vertical ConcretePlywood Forming to plane each wall side in SF = Linear Foot of Wall * Wall Height
Underground PilingVolume of Concrete per Cylindrical Pile = 1/2 Pile width in feet (radius) squared * Pile Depth (height)
Rebar and ReinforcementWeight of Rebar = Gauge of Rebar in LF (total from horizontal and vertical equations) X Weight per pound
Horizontal RebarLF of rebar = LF of concrete being reinforced * Spacing (in feet) = Stick count * length of concrete being reinforced (to control joint)
Vertical RebarLF of rebar = LF of concrete being reinforced * Spacing (in feet) = Stick count (this will be different than the horizontal if the slab is thick enough to need more than one row of reinforcement) * length of concrete being reinforced (to control joint)

Rebar & Reinforcement

TypeCalculation
Rebar and ReinforcementWeight of Rebar = Gauge of Rebar in LF (total from horizontal and vertical equations) X Weight per pound
Horizontal RebarLF of rebar = LF of concrete being reinforced * Spacing (in feet) = Stick count * length of concrete being reinforced (to control joint)
Vertical RebarLF of rebar = LF of concrete being reinforced * Spacing (in feet) = Stick count (this will be different than the horizontal if the slab is thick enough to need more than one row of reinforcement) * length of concrete being reinforced (to control joint)

Drywall

TypeCalculation
Drywall: By SheetLinear foot of Wall * Wall Height = Total Square foot of one Side of Wall / Drywall Sheet area in square foot = Sheet Count

Electrical

TypeCalculation
Wiring by Fixtures Count and then LF, and then CFMTotal LF of Wiring = Fixtures Count * Not To Exceed LF Allowance + Homeruns with NTE LF Allowance
Linear Foot of Wire into SpoolsSpool Count = Total LF of Wire (by gauge or assumed) / Spool Length (typical 500LF)

To convert Square Feet to Cubic Yards:

Total SF * Depth (or Thickness in Lineal Feet) / 27 = Cubic Yards

To Convert Lineal Feet to Cubic Yards:

Total LF  * Width (in Lineal Feet) * Height (Lineal Feet) / 27 = Cubic Yards

To Convert Lineal Feet to Square Feet:

Total LF * Height (in Lineal Feet) = Square Feet

TIP: This can be used for things like wall area for drywall & insulation. This can also be multiplied by additional factors for things like double layers, etc.

To Convert Lineal Feet to Each (for studs):

Total LF / Spacing (in Lineal Feet) = Each

TIP: This works best for stud counts and items where you measure a distance, then figure how many items are there from the indicated spacing

To Convert Lineal Feet to Each (for board counts from total LF):

Total LF / Length (in Lineal Feet) = Each

TIP: This works best for board counts and items where you measure a distance, then figure how many items are there from the length of the desired board/material

To Convert SF to Each:

Total SF / SF per piece (think of a 4’x8’ piece of drywall) = Each

TIP: This works best for piece counts for things like drywall or plywood where each sheet covers a certain amount of square feet (e.g. 480 Total SF / 48 SF per sheet (4’x12’) = 10 sheets)

Quick Guide to decimal conversions from Inches to Feet (1-11 inches):

1” = 0.0832” = 0.1663” = 0.254” = 0.3335” = 0.4166” = 0.57” = 0.5838” = 0.6669” = 0.7510” = 0.83311” = 0.916

Ready to throw away your estimating calculator and get building? Head over to our Learning Center or schedule a personalized software demo with a 1build Solutions Engineer.

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