Scientific Calculator
Trig (degrees), log, square root, π, e supported
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Scientific calculator
Handles trigonometry, logarithms, and powers for science and engineering.
Supports degree-based trig (sin, cos, tan), log, square root, π, and e.
- Enter an angle in degrees to get sin, cos, and tan.E.g. sin(30°) = 0.5, cos(30°) = √3/2, tan(30°) = 1/√3.
- Compute common log (base 10) and natural log (ln).E.g. log₁₀(100) = 2, ln(e) = 1.
- Trigonometric functions
- Sine, cosine, and tangent relate an angle of a right triangle to ratios of two sides. They are widely used in geometry, physics, and signal processing.
- Logarithm
- The logarithm is the inverse of exponentiation. log_a(b) is the exponent to which a must be raised to get b. Base 10 is common log; base e is natural log (ln).
When a scientific calculator gives an odd answer
Unexpected results almost always trace back to one of three things: the angle mode, which logarithm you are using, or the order of operations.
Degrees versus radians
sin(30) means different things in different modes. In degrees it is 0.5; in radians it is about −0.988.
This calculator works in degrees. Textbooks and most programming languages default to radians, so if your answer disagrees with another source, check the mode first. To convert degrees to radians, multiply by π/180.
log and ln have different bases
log normally means base 10 and ln means base e (about 2.71828). log(100) = 2 but ln(100) ≈ 4.605.
Conventions vary by field: some mathematics writing uses log to mean the natural logarithm, and in computer science it often means base 2. If a value does not match a reference, suspect the base before suspecting the calculator.
Order of operations
Calculations run in this order: brackets, then exponents, then multiplication and division, then addition and subtraction. So 2 + 3 × 4 is 14, not 20.
Negative numbers with exponents catch people out. −3² means −(3²) = −9, while (−3)² = 9. If you want to square a negative number, the brackets are not optional.
Why decimals do not land exactly
0.1 + 0.2 can display as 0.30000000000000004. Computers store decimals in binary, and 0.1 has no exact binary representation.
The error appears far below the fifteenth decimal place, so it rarely matters in practice. For money or anything that must reconcile exactly, decide on a rounding step at the end of the calculation.
Undefined results
Dividing by zero, taking the logarithm of a negative number, and taking the square root of a negative number are all undefined over the real numbers and return an error.
tan(90°) is the same case: the tangent grows without bound at 90 degrees, so there is no value. Some calculators show a very large number instead, which reflects an internal approximation rather than a real result.
Frequently asked questions
- Why isn't sin(30) giving me 0.5?
- The angle mode is probably set to radians. In degrees sin(30°) = 0.5; in radians sin(30 rad) ≈ −0.988.
- Should I use log or ln?
- log for base 10, ln for base e. Quantities built on powers of ten — pH, decibels, the Richter scale — use log; growth, decay and most calculus use ln.
- Why does −3 squared give −9?
- Exponents bind tighter than the minus sign, so −3² is −(3×3) = −9. Write (−3)² if you want 9.
- Why isn't 0.1 + 0.2 exactly 0.3?
- It is a structural property of binary floating point and happens on every calculator and computer. The discrepancy sits below the fifteenth decimal place.
- Why does tan(90) return an error?
- That is correct behaviour. The tangent is undefined at 90 degrees because it diverges to infinity. The same applies at 270 degrees.