Arc Chord and Mid-Ordinate Check Calculator
Prove a struck arc before it is masked: the chord between check stations and the offset from that chord to the curve, for a given radius.
Imperial / Metric
Measurements & Conversions
Geometry, slopes & trade sizes
The measurements that are not a straight swap between two units.
- 14Calculators
- 14Work in imperial
- 12Work in metric
What this covers
Slope expressed in degrees, in per cent, as a roof pitch and as a fall; the circle work behind a curved wall or a bend — radius from area, area from radius, circumference, and the chord and mid-ordinate a surveyor checks an arc with; squaring a rectangle by its diagonal; and the nominal timber names that are not the timber's size.
What decides which one you need
Which convention the number was written in, because a slope has four and none of them carries a symbol that distinguishes it. "Four" can mean four degrees, four per cent, a one-in-four fall or four inches of rise in a foot, and the four differ by an order of magnitude at the shallow end where drainage lives. A figure without its convention is not a slope, and the pages here ask for it rather than guessing.
What this does not cover
Whether the slope is adequate — the minimum fall on a gutter, a drain or a ramp is a code question.
Every calculator in this family
14 calculators
Area to Radius Calculator
Work out the radius of a circle that encloses a given area — for patios, tanks, planting beds and turning circles.
Imperial
Board Feet Calculator
Convert lumber dimensions (thickness x width x length) into board feet, the standard unit lumber is priced by.
Imperial / Metric
Circumference Calculator
Find the circumference and radius of a circle from its diameter, for round posts, pipes, or tanks.
Imperial / Metric
Equal Spacing Calculator (Balusters or Spindles, Posts, Battens)
Space balusters, posts, battens or fixings equally: the fewest that keep every gap or centre under your maximum, and each mark from one end.
Imperial / Metric
Squaring Calculator for Layout and Setting Out (3-4-5 Rule)
Check a building layout is square: the diagonal it should read, the largest 3-4-5 triangle to strike, and how far and which way to move a corner.
Imperial / Metric
Lumber Dimensional Size Calculator
Look up the actual (dressed) size of a nominal lumber dimension like a 2x4.
Imperial / Metric
Radius to Area Calculator
Convert a measured radius into circular area for material take-off on curved and round work.
Imperial
Court Diagonal and Squaring Triangle Calculator
The diagonals of a sports court: what the corner-to-corner tape should read, how far apart the two may be, and the scaled 3-4-5 triangle to set it out.
Imperial / Metric
Roof Pitch to Angle Calculator
Convert a roof pitch (rise per 12 units of run) into its equivalent angle in degrees and slope percent.
Slope Degrees to Percent Calculator
Convert a measured slope angle into a percentage gradient for drainage and civil drawings.
Slope & Grade Calculator
Convert a rise and run measurement into slope percentage and angle in degrees.
Imperial / Metric
Slope Percent to Degrees Calculator
Convert a percentage gradient into degrees for setting out drainage, ramps and driveways.
Triangle Calculator — Right Triangle and Any Triangle Solver
Solve a right triangle from any two of rise, run, slope length and angle, or any triangle from three known parts: every side, every angle and the area.
Imperial / Metric