Disclaimer
Every calculator here performs arithmetic on values you provide. It is not a substitute for your code book — the Canadian Electrical Code, the NEC, or whichever your jurisdiction has adopted — your local amendments, or the judgement of a qualified person. Verify every result against your code book and your authority having jurisdiction before you install anything.
What the tool is responsible for
The trigonometry. The multipliers, the shrink, the mark spacing — those are derived from the angle and tested against known values, and they are shown openly on each page so you can check them yourself. If a formula on this site is ever wrong, that is on the site.
What you are responsible for
The inputs and the outcome. A right answer to the wrong number is still the wrong bend. Take-up read off the tool, the depth you measured, which end you marked from, the condition of the pipe and the bender, and whether the finished work meets code — all of that is your call, made on site, and no calculator can make it for you.
Which question is which
The line is easier to hold if you can see both sides of it at once. These are the two piles every question on a job falls into.
Questions this site answers
How far apart do my two marks go for this rise at this angle. How much length do those bends eat. Where does the mark go for a stub of this height with the take-up my bender has. How much further along does the second run in a rack start so the pair stays parallel. How do I read 0.4375 off a tape.
All geometry, all from the numbers you type, all shown with the formula beside them so you can check them.
Questions for the book and the AHJ
How many degrees of bend may I put between pull points. What is the minimum radius for this trade size. How far apart do the straps go. How full may the conduit be. Is this method permitted in this location at all. Which edition applies here, and what have the local amendments changed.
Not one of those figures appears anywhere on this site, on purpose. They are in your code book, and the authority having jurisdiction has the last word on how they are read — here is what that looks like in practice.
If the site and your bender disagree
Your bender wins. Every time. The trigonometry on this page is exact; the tool in your hands is a real object with a shoe that wears, a pipe that springs back, and a stamped figure that was true for one wall thickness. When a mark comes out consistently off by the same amount, that is not a mistake in the arithmetic — it is a measurement you have not taken yet. Take it once, use your own figure, and stop arguing with the stamp.
Units and rounding
In imperial, results are rounded to the nearest sixteenth of an inch because that is what a tape reads, with the decimal shown small beside them so you can see which way it went. In metric — the Imperial/Metric switch at the top of every page — they are rounded to the whole millimetre. Rounding happens once, at the end — never part way through — so the error in any mark is at most half a sixteenth or half a millimetre from the exact figure, and that is smaller than the line your pencil draws.
Where a shop rule of thumb is shown beside an exact multiplier, the two are genuinely different numbers and the gap grows with the rise. The multiplier page puts a figure on how far apart they get.
The worst a mistake here should cost you is a stick of pipe. The site does not size conductors, size services, or produce anything structural on purpose, so that a wrong figure never becomes a wrong that matters. Use it as the tape measure it is, and check your work.