United States · Roofing

Gutter Calculator

Estimate gutter sections and downspouts from roof-edge length and chosen spacing. Enter project measurements and product assumptions that match your job and local supplier information.

US customary unitsRuns in your browserFormula & assumptions ↓

Your inputs

Your results

Enter your values and calculate to see the result.

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How this Gutter Calculator works

The calculator uses total gutter run, gutter section length, downspout spacing, extra gutter allowance. Inputs remain editable so the estimate can reflect the actual project instead of a fixed national price or product assumption.

Formula and assumptions

The result is calculated from the measurements and rates entered above using standard geometry and unit conversions. Where a density, coverage, spacing or waste factor is requested, use the specification for the material you plan to buy.

How to get a better estimate

Measure the finished project area carefully, separate irregular sections when useful, and include realistic waste for cuts, breakage, compaction or field adjustments. For structural or code-sensitive work, this quantity estimate does not replace approved plans, span tables, engineering or local building-code requirements.

Browse all US home & construction calculators for more material, framing, roofing, concrete and landscaping tools.

How to use this calculator

  1. Set Total gutter run (default 180).
  2. Set Gutter section length (default 10).
  3. Set Downspout spacing (default 40).
  4. Set Extra gutter allowance (default 5).
  5. Select Calculate to update the result. Reset restores the starting values.

Planning estimate only. Product dimensions, site conditions, local codes, installation methods and manufacturer coverage can change final quantities. Confirm final orders with your supplier or contractor.

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