Use this construction calculation for preliminary quantity, geometry, material, load, or coverage planning when dimensions and units have been measured consistently.

First-to-last center span (m)

Required number input.

Bar count

Required integer input.

Find equal center-to-center spacing for bars whose first and last centers span a known distance. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Center spacing (m)

The resulting center spacing returned as a number.

• A quantity estimate or simplified engineering formula is not a building-code check, stamped design, manufacturer approval, or site inspection. Material properties, tolerances, waste, moisture, workmanship, loads, local conditions, and code requirements can change the result.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Verify dimensions on site, use current product data and local code requirements, include an explicit waste or safety allowance where appropriate, and obtain qualified structural, electrical, plumbing, or geotechnical review when required.

• Rebar Stirrup Spacing

  Equal center spacing when a selected number of stirrups spans from first to last center over a specified cage length.

• Rebar Chair Spacing

  Count support chairs along one rebar line including both ends, with no gap exceeding the chosen maximum spacing.

• Rebar Stirrup Count

  Minimum stirrup count including both ends when no center-to-center interval may exceed a user-specified maximum.