Rebar centreline bend schedule and cut length calculator

Measure straight lengths to the bend tangencies

A centreline cut length is the sum of its straight and curved portions. The straight input must stop at the tangent points where curvature begins. Entering an overall outside dimension as though it were a tangent length would count some material twice.

For each row, enter a sum of straight tangent lengths and the list of bend angles. All bends on that row share the entered inside radius. Use another row when another radius or diameter is needed.

The theoretical rebar weight calculator starts from an entered bar length. This bending schedule first calculates the centreline arcs from actual bend angles and inside radius, then applies theoretical mass to the resulting cut length.

Inside radius is not the centreline radius

The bar’s centreline lies half a bar diameter outside the inside surface of the bend. Its arc radius is therefore inside radius plus half the diameter. Multiplying by the bend angle in radians gives the centreline arc length.

Degrees are converted by multiplying by pi over 180. Two ninety-degree bends have the same total angle as one half-turn for the same centreline radius, but their physical placement and straight segments can be very different.

Theoretical mass comes after the cut geometry

Once per-bar length is established, the tool multiplies by the mark count and the equivalent circular area at the entered density. This is a geometric mass estimate rather than a supplier certificate.

Required hooks, laps and tail lengths must be supplied in the appropriate straight or curved components. The calculator does not generate a code-compliant bar shape, determine minimum bend radius or apply bending deductions from outside-dimension schedules.

Work through the example

Ten 12 mm bars with 2,000 mm straight tangent length and two 90-degree bends at a 30 mm inside radius need about 2.1131 m each. The bends use a 36 mm centreline radius, not the inside radius.

Use the worked table to trace where each input enters. Then change one assumption and calculate again, leaving the others fixed. A comparison is easier to interpret when the change has one identifiable cause rather than a different set of measurements, dates and rates all at once.

What this model does not establish

Centreline geometry only. Straight lengths must be tangent-to-tangent; hooks, laps and tails require explicit entries. No structural design, code minimum radius, outside-dimension bend deduction, stock optimization or certified manufacturing mass.

Keep the input assumptions with any exported result. Illustrative values do not become observations merely because the output is precise. For a real purchase, financial reconciliation or technical decision, check the underlying records and applicable requirements before treating this scenario as a final answer.