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Free Triangle Template Generator

Create equilateral, isosceles and right triangles, or set a base and two angles for a custom triangle. Add a centroid or perpendicular height guide.

Lengths: 1–1000 mm (0.0394–39.37 in). Switching units preserves the physical size.

More options
Labels are omitted on small shapes. Dimensions are measured at line centers.

Print at Actual size / 100%. Turn off Fit to page. Check that the scale line measures 50 mm (1.97 in).

Print preview

The preview is scaled to fit. PDF keeps the actual dimensions.

Choose how to define your triangle

Use a side length for an equilateral triangle, or base and perpendicular height for an isosceles or right triangle. Custom triangles use a horizontal base and the bottom-left and bottom-right interior angles. The apex angle is 180° minus those two angles. Each base angle must be 0.1–179.9°, and their sum must be below 180°.

Acute, right and obtuse triangles

60° and 60° gives an equilateral triangle. 45° and 45° gives an isosceles triangle with a right angle at the apex. 110° and 30° gives an obtuse triangle. Use Mirror to swap the two base angles.

Frequently asked questions

Is height the sloping side?

No. Height is perpendicular to the base. An equilateral triangle has height equal to side length × √3 / 2.

What do the guides show?

The centroid is the intersection of the medians, one third of the height above the base. The height guide drops perpendicularly from the apex and extends the base if needed. B and H in PDF labels mean base and height; length labels use centimeters.

Print at actual size

  1. Select a shape and enter the dimensions in inches, cm or mm.
  2. Choose one shape, fill the sheet or enter a quantity. Choose paper and orientation in More options.
  3. Download PDF or open Print. Select the matching paper and Actual size / 100%, with headers, footers, Fit to page and borderless enlargement off.
  4. Measure the 50 mm scale line and the shape before cutting.

US Letter, US Legal, A4 and A3 are supported. Large shapes are tiled with a 5 mm overlap, up to 200 pages. ROW and COL identify tile positions; COPY identifies the shape. Trim the light borders and align the overlap marks. Quantity can be set from 1 to 500, subject to the page limit.

Lengths are measured at line centers. No seam allowance is added. Input and PDF generation stay in your browser, with no account or upload required. Free for personal and commercial use.