PipeMath
LiveRolling offsets, grade & cuts
On the App Store as “Pipe Offset Calculator”
Free rolling offset calculator
How do you calculate a rolling offset?
To calculate a rolling offset, square the set (vertical rise) and the roll (horizontal shift), add them, and take the square root: true offset = √(set² + roll²). Then divide the true offset by the sine of the fitting angle to get the travel, and by the tangent to get the run. With 45° fittings, travel is the true offset × 1.4142.
Fitting angle
True offset
17″
17.00″ · 1′ 5″
Travel
24-1/16″
24.04″ · 2′ 1/16″
Run
17″
17.00″ · 1′ 5″
Cut length — subtract fitting takeouts
Travel is center-to-center; the fittings cover part of it. Cut length = travel − the takeout of each fitting.
Results round to the nearest 1/16″ — the same engine as the app.
Take it to the jobsite
The full app adds simple offsets, drainage grade, cut lengths with fitting-takeout reference, labeled diagrams drawn to your angle, and a 1/16″ keypad built for gloved hands — fully offline, inputs saved between opens.
Free web tool
How do you calculate a pipe offset (travel and run)?
A simple pipe offset is a right triangle: the offset is how far the line steps over, the run is how far it advances, and the travel is the diagonal length of pipe you cut between the two fittings — so travel = offset ÷ sin(angle) and run = offset ÷ tan(angle), where the angle is the fitting angle (22.5°, 30°, 45°, 60°, or 90°). A 10-inch offset through 45° fittings gives a travel of 10 ÷ sin 45° ≈ 14.14″ — about 14-1/8″ — with a 10″ run, because the 45° triangle is symmetric. A 12-inch offset through 30° fittings gives 12 ÷ sin 30° = 24″ of travel (2′ 0″) and 12 ÷ tan 30° ≈ 20-13/16″ of run, and a straight 90° turn makes the travel equal the offset with zero run. Read the travel to the nearest 1/16″, mark it center-to-center, and remember these are theoretical lengths — subtract each fitting's takeout before you cut.
Fitting angle
Travel · diagonal pipe length
14-1/8″
14.14″ · 1′ 2-1/8″
Run · advance along the line
10″
10.00″
travel = offset ÷ sin(angle) · run = offset ÷ tan(angle) · rounded to the nearest 1/16″ · the same engine as the app.
Take it with you
The full Pipe Offset Calculator app adds rolling offsets, drainage grade, and cut lengths with a fitting-takeout reference, plus labeled diagrams drawn to your angle and a 1/16″ keypad built for gloved hands — fully offline, with inputs saved between opens.
What it is
A jobsite calculator for plumbers and pipefitters covering the four calculations they run every day: rolling offsets, simple offsets, drainage grade, and cut lengths. Big type you can read across a trench and a fraction keypad built for gloved hands, not a spreadsheet. Works offline.
Why we built it
The trade's everyday offset math usually happens on paper or in calculators built for decimals, not tape measures. Pipefitters needed one tool that speaks feet-inches-sixteenths, draws the fitting so you know which number is which, and stays readable in a crawlspace. That exact, trade-specific tool was missing.
Want one like this?
PipeMath is one of 92. We can build yours.
Every app on the shelf started as one honest problem, scoped small and built native, end to end. That’s exactly how we approach client work — designed, built and shipped, without the bloat.
