Free Construction & DIY Calculators

Materials, quantities and system sizing — every tool giving both the exact figure and the number you actually have to buy.

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A
B
C
D
E
F
G
H
I
L
M
P
R
S
T
W

A 3 tools

AC BTU Calculator Estimate the air conditioner size a room needs in BTU per hour and cooling tons. Air Changes Per Hour Calculator Find ACH from room volume and airflow, or the airflow needed for a target ACH. Asphalt Calculator Calculate tons of hot-mix asphalt, truckloads and cost from area and compacted depth.

B 7 tools

Baluster Spacing Calculator Get the baluster count and even gap for a railing run that satisfies the 4-inch rule. Beam Deflection Calculator Calculate beam deflection for standard load cases against the L/360 and L/240 limits. Beam Load Calculator Find reactions, maximum shear and maximum bending moment for a loaded beam. Board and Batten Calculator Get batten count, exact even spacing and material cost for a board and batten wall. Board Foot Calculator Convert lumber dimensions into board feet, volume and total cost for any piece count. Bolt Torque Calculator Convert bolt preload into tightening torque with the nut factor K stated openly. Brick Calculator Count bricks, mortar bags and cost for a wall by brick size, bond and joint thickness.

C 6 tools

Column Buckling Calculator Calculate Euler critical buckling load, slenderness ratio and critical stress. Concrete Block Calculator Count CMU blocks, courses, mortar bags, grout and rebar for a concrete block wall. Concrete Column Calculator Get concrete volume, bag count and cost for round or rectangular columns and piers. Concrete Stairs Calculator Concrete volume, bags and formwork area for a poured stair flight, in imperial or metric. Cross-Sectional Area Calculator Cross-sectional area of pipes, bars, beams, ducts and cables, with weight and stress per section. Cubic Yard Calculator Convert length, width and depth into cubic yards, cubic metres and cubic feet.

D 2 tools

Decking Calculator Work out deck boards, linear footage, joists, fasteners and cost from your deck size. Drywall Calculator Work out drywall sheets, joint compound, tape and screws for a room, minus openings.

E 3 tools

Electrical Box Fill Calculator Applies the NEC 314.16 box fill counting rules and compares the result with your box volume. Elevation Grade Calculator Convert grade between percent, ratio, degrees and rise over run, and apply it across a distance. Epoxy Resin Calculator How much epoxy a pour needs, split into resin and hardener at your product's own mix ratio.

F 5 tools

Factor of Safety Calculator Factor of safety and margin of safety from material strength and the applied working stress. Feet and Inches Calculator Add, subtract, multiply and divide feet-inch-fraction measurements and convert them to metric. Fence Calculator Work out fence posts, rails, pickets or panels, concrete per post hole and total cost. Floor Joist Calculator Joist count, blocking and rim length plus bending, shear and deflection checks on the span. Furnace Size Calculator Turns a design heating load into the BTU/h output and nameplate input rating a furnace needs.

G 2 tools

Gravel Calculator Work out the cubic yards, tonnage, bag count and cost of bulk aggregate at any depth. Grout Calculator How much tile grout an area needs, from tile size, joint width and joint depth, plus bags.

H 1 tool

Heat Loss Calculator Estimate building heat loss from envelope U-values, areas and infiltration in BTU/h and watts.

I 1 tool

Insulation Calculator Work out insulation bags for an attic or wall and the R-value the assembly delivers.

L 1 tool

Land Area Calculator Calculate plot area from measured dimensions and read it in acres, hectares, square feet and square metres.

M 2 tools

Material Weight Calculator Weigh plate, bar, tube, pipe, hex and angle stock in steel, aluminium, copper or brass. Miter Angle Calculator Find the miter and bevel saw settings for any corner angle, including compound crown moulding cuts.

P 4 tools

Paver Calculator Work out paver count, base aggregate, bedding sand, edge restraint and joint sand. Pipe Volume Calculator Calculate the internal volume of a pipe run in gallons or litres, plus the weight of its contents. Plywood Sheet Calculator Work out how many plywood sheets an area needs, with waste factor, layout count and total cost. Pool Volume Calculator Work out pool volume in gallons or litres, including a sloped shallow-to-deep floor.

R 5 tools

Rafter Length Calculator Calculate common, hip and jack rafter lengths plus plumb and seat cut angles from span and pitch. Rebar Calculator Work out rebar count, linear length including laps, tie count and steel weight. Retaining Wall Calculator Estimate blocks, caps, base gravel and backfill for a segmental retaining wall, with total cost. Roof Pitch Calculator Convert roof pitch between rise over 12, degrees, percentage grade and slope factor. Roofing Calculator Turn a building footprint and roof pitch into roofing squares, shingle bundles, rolls and cost.

S 8 tools

Section Modulus Calculator Calculate elastic section modulus, second moment of area and plastic modulus for standard shapes. Siding Calculator Work out squares of siding, panel count, starter strip, trim length and cost for a house. Snow Load Calculator Calculate flat and sloped roof snow load from your mapped ground snow load using the ASCE 7 method. Sod Calculator Calculate sod rolls, pallets and turf cost for any lawn area, with waste allowance and metric support. Soil Volume Calculator Calculate soil volume for raised beds, borders and pots, then compare bagged and bulk delivered cost. Spindle Speed Calculator Convert spindle RPM, surface cutting speed and feed rate for milling, turning and drilling jobs. Square Footage Calculator Sum the square footage of multiple rooms and odd shapes, then add waste and cost. Stair Calculator Work out riser count, riser height, total run, stringer length and headroom for a flight.

T 1 tool

Tank Volume Calculator Find tank capacity and the volume at any liquid depth for cylindrical, capsule and cone-bottom tanks.

W 3 tools

Wall Framing Calculator Get stud count, plate footage, headers and blocking for a wall at 16 or 24 in on centre. Wheelchair Ramp Calculator Work out ramp run, slope, angle and landings for any rise, against the published ADA 2010 figures. Wood Beam Span Calculator Run bending, shear and deflection checks on a wood beam and see which one governs the span.

No construction & diy tool matches that. Search all 1141 free tools.

The round-up is the point

A calculation that tells you a job needs 7.3 sheets of drywall has not finished the job. Every tool here takes a waste factor with a stated default, then converts the raw quantity into whole sheets, bags, bundles or lengths — because that is the number you take to the merchant, and the gap between the two is where a second trip comes from.

One tool with a material selector, not ten thin pages

Roughly 43% of the competing construction category is a single calculation restated once per material: ten aggregate pages, eleven fence pages, nine material-weight pages. The gravel, fence and material-weight tools here each carry a proper selector with a sourced density or coverage table, which covers all of those cases on one page that is worth reading.

Code-bound tools say so

Stair rise and run, stud spacing, rebar placement, insulation R-values and equipment sizing are all governed by codes that differ by jurisdiction and climate zone. Those pages cite the standard they used and state which zone it applies to, and every one of them says plainly that local code and a licensed professional decide the final answer. No figure on these pages was invented; each comes from the source linked beside it.

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