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Golden Rectangle Calculator

From the long side, short side, diagonal, area or perimeter, derive the whole golden rectangle — and see it drawn with its golden-spiral subdivision.

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Rectangle diagonal calculatorCompute the diagonal, area and perimeter of a rectangle.Rectangle calculatorEvery property of a rectangle from any two you know. Pick what you have — length & width, area & a side, perimeter & a side, or diagonal & a side — and it returns the length, width, area, perimeter and diagonal, using A = l·w, P = 2(l+w) and d = √(l²+w²).Golden Ratio CalculatorSplit a length in the golden ratio φ = (1+√5)/2: give the total, the larger or the smaller segment and get the other two, drawn to scale.3D Distance CalculatorCompute the distance between two points in space, with an isometric view, the Δx / Δy / Δz components and the midpoint.Angle Bisector Calculator (triangle)Enter the three sides or the three vertices and get the length of each internal angle bisector, the incenter, the inradius, and the exact point where every bisector cuts the opposite side. The angle bisector theorem is the heart of it: the bisector splits the opposite side in the ratio of the two adjacent sides. The triangle inequality is checked before anything is computed, and the triangle is drawn with its three bisectors.Circumscribed Circle CalculatorCircumradius R = abc/4K, circumcentre and circumcircle of a triangle, from three sides or three vertices, with the figure drawn.Distance Formula CalculatorFind the distance between two points on an interactive coordinate plane, with the Pythagorean working, the midpoint, the slope and the direction angle.Frustum CalculatorVolume, lateral and total surface area, and slant height of a conical frustum.

Golden Rectangle Calculator works straight from this page — free, instant, nothing to install. Its place is under Geometry; Rectangle diagonal calculator and Rectangle calculator answer the questions closest to this one.

How to use it

  1. Open the tool — no signup or install needed.
  2. Enter your input or adjust the available options.
  3. Get your result instantly, then copy or download it.

Frequently asked questions

What is Golden Rectangle Calculator?

From the long side, short side, diagonal, area or perimeter, derive the whole golden rectangle — and see it drawn with its golden-spiral subdivision.

When would I actually use this?

Homework and site work alike: how much paint a wall takes, how much water a tank holds, whether a corner is square — and, on the coordinate side, the slope between two points, the distance across a plan, the midpoint of a span.

What is the most common mistake?

Mixing units inside one shape. Entering a length in centimetres and a width in metres gives an area wrong by a factor of a hundred, and the result looks perfectly plausible.

How is Golden Rectangle Calculator different from Rectangle diagonal calculator?

They sit next to each other but answer different questions: Rectangle diagonal calculator is the one to open when you need it to compute the diagonal, area and perimeter of a rectangle. Pick whichever matches what you're starting from — both are free.

Is there a tool for the next step?

Rectangle calculator is the closest one after this: Every property of a rectangle from any two you know. Pick what you have — length & width, area & a side, perimeter & a side, or diagonal & a side — and it returns the length, width, area, perimeter and diagonal, using A = l·w, P = 2(l+w) and d = √(l²+w²).

What else is worth having open alongside it?

Golden Ratio Calculator and 3D Distance Calculator — they come up in the same task often enough to be worth a second tab.

Where do the figures come from?

The formulas are the classical ones and the results are exact to the precision shown — geometry does not change with the year or the country, so nothing here needs updating.

Further reading

All guides →
How-toHow to Find the Distance Between Two PointsUse the distance formula d = √((x₂−x₁)² + (y₂−y₁)²) to measure the straight-line distance between two points on a plane, with a worked example and the midpoint too.How-toHow to Calculate the Slope of a Line: Rise Over RunFind the slope of a line from two points with m = (y₂ − y₁) / (x₂ − x₁), and read what a positive, negative, zero, or undefined slope tells you.ExplainerWhat Is a Z-Score? Standard Deviations Above the MeanA z-score is z = (x − μ) / σ — how many standard deviations a value sits from the mean. Learn how to compute it, read the standard normal curve, and turn it into a percentile.How-toHow to Use the Quadratic Formula: Solving ax² + bx + c = 0Solve any quadratic equation with x = (−b ± √(b² − 4ac)) / 2a, and read the discriminant to know how many real solutions to expect.ExplainerSignificant Figures Explained: Counting, Rounding, and Why They MatterLearn what counts as a significant figure, the rules for leading, trailing, and captive zeros, and how sig figs keep your calculated answers honest.ExplainerDegrees to Radians: The Conversion ExplainedConvert between degrees and radians with radians = degrees × π/180 (and back with × 180/π), understand why 180° = π, and learn the common angles by heart.
Golden Rectangle Calculator — OneKitly