Copper Rolling Offset Calculator

The tool is set to 3/4 inch copper with 45 degree fittings. Change the size in the take-off box.

True offset (set): –
Travel: –
Run: –
Cut length: –

Not to scale. Dots are the pipe center lines at each fitting. Travel is the long diagonal through the box.

Formulas: true offset = √(rise² + roll²), travel = true offset ÷ sin(angle), run = true offset ÷ tan(angle). Right-triangle geometry, explained here. Formulas and take-off sources last checked October 20, 2026.

Copper take-off per 45 degree fitting

Take-off here is dimension C, the center of the fitting to the bottom of the cup. The tool subtracts it twice.

Copper, solder take-off per 45 degree fitting by pipe size
Pipe size	Take-off (in)	Decimal
1/2"	9/32	0.281
3/4"	11/32	0.344
1"	3/8	0.375
1 1/4"	17/32	0.531
1 1/2"	19/32	0.594
2"	25/32	0.781
2 1/2"	29/32	0.906
3"	1 1/8	1.125
4"	1 9/16	1.563

Source

NIBCO 606 wrought copper 45° elbow, dimension C (catalog page 11, revision 5/9/2013)

The 1 inch value is 3/8, as NIBCO prints it. It sits low between the 3/4 and 1-1/4 inch values, so measure that fitting before you rely on it. Other makers differ by a small amount.

Worked example

Rise 12 inches, roll 9 inches, 3/4 inch copper. Travel is 21 3/16". Take-off is 11/32 inch per fitting. Cut length = 21.21 - 2 x 0.344 = 20.53 inches, about 20 1/2".

Tips for copper

Cut the tube square and measure from the bottom of the cup, not the end of the fitting.
Dry fit and mark the tube depth in each cup before you solder.
The table is for 45 degree fittings only. For other angles, type your own take-off.

Questions

What is the take-off of a 3/4 inch copper 45 degree elbow?

11/32 inch (0.344), from NIBCO 606.

Does the cut length include the cup depth?

The tube bottoms out in the cup. Center to cup bottom is the take-off, so the cut length is the tube length between the two cup bottoms.

Calculators for specific jobs

Each page opens the calculator with the right settings and adds the charts for that job.