Geometry & Trigonometry calculators
Geometry answers questions about shape and size; trigonometry answers questions about angles and the lengths tied to them. Together they cover almost everything measured on a building site, a workshop bench, a survey traverse or a drawing board. These calculators handle plane figures, solid volumes, triangle solving from whatever combination of sides and angles you actually managed to measure, and the unit conversions that keep those numbers consistent.
18 calculators in this category
Most used geometry & trigonometry calculators
Choose the formula that matches what you can measure
Most geometry mistakes come from using a formula that needs a measurement you do not really have. A triangle's area from base and height requires a perpendicular height, which is awkward to establish on uneven ground; Heron's formula needs only the three edge lengths, which a tape gives you directly. A tank's capacity needs the internal radius, not the outside diameter of a thick-walled vessel. Pick the formula that fits your measurements rather than forcing the measurements to fit a remembered formula.
Triangle solving works the same way. Two angles and a side call for the law of sines; two sides and the angle between them call for the law of cosines; three sides call for the law of cosines rearranged. Only one of these configurations — two sides and a non-included angle — is genuinely ambiguous, and knowing which one it is saves a great deal of rework.
Scaling laws decide more than the formulas do
Length, area and volume scale with the first, second and third powers of size. Doubling a circle's radius quadruples its area; doubling a tank's dimensions multiplies its capacity eightfold while only quadrupling the material needed to build it. This single relationship explains why bulk storage is cheap per litre, why large animals overheat, why small droplets evaporate quickly, and why comparing two pizzas by diameter is misleading.
It also governs error. Because area depends on the square of a linear measurement, a 2% measuring error becomes a 4% area error; for volume it becomes about 6%. Measure the dimension that gets raised to the highest power most carefully, and prefer a measurement you can take reliably — a circumference with a tape beats a diameter guessed across a curved surface every time.
Angles: units, conventions and the mistake everyone makes
Angles arrive in degrees, radians, gradians, degrees-minutes-seconds, and as rise-over-run ratios or percentage grades. All describe the same thing, and mixing them silently produces answers that look reasonable and are badly wrong. The most frequent error in the whole category is feeding degrees to a trigonometric function that expects radians, in a spreadsheet or a piece of code, and never noticing.
Construction conventions add their own traps. A 6:12 roof pitch is a slope of 0.5 and an angle of 26.57°, not 6°. A 1:12 accessibility ramp is a 8.33% grade and a 4.76° angle. A 10% road grade is a slope of 0.10, not a 10° incline. Every calculator here states its unit explicitly and shows the conversion, precisely because these confusions are so costly.
Every geometry & trigonometry calculator
Geometry & Trigonometry calculator questions
Do the trigonometry calculators use degrees or radians?+
Where an angle is entered, the field states the unit, and results show the equivalent value in the other unit. Enter degrees where degrees are asked for; the conversion to radians happens internally.
How do I calculate the area of an irregular shape?+
Split it into triangles and rectangles, calculate each, and add them. For a plot measured only by its edges, the triangle area calculator's Heron mode handles each triangle from side lengths alone.
Why is a half-depth horizontal tank exactly half full but a quarter-depth one not a quarter full?+
Because a circle is widest at its middle. The sector area calculator computes the circular segment at any fill depth, which is why tank gauging needs a strapping table rather than a linear scale.
What units should I use?+
Any, as long as they are consistent throughout one calculation. Enter metres and you get square metres and cubic metres out. Never mix metres with feet in the same shape.