Evaluation order
- 1. Brackets and named functions
- 2. Factorials, percentages and powers
- 3. Multiplication and division
- 4. Addition and subtraction
Scientific Calculator
Calculate square roots, powers, percentages, logarithms, trigonometry and everyday arithmetic without leaving MedMaths.
General & scientific
Scientific calculator
Type an expression or use the keypad. Brackets and powers follow standard order of operations.
Enter a value and then select √, sin, log or another one-value function for an immediate result—or type the complete expression yourself. Keyboard: use * for multiply, / for divide, ^ for powers, Enter for equals and Esc to clear.
Try an example
A calculator checks arithmetic, not the meaning of the inputs
Confirm the formula, units, source values, angle mode and rounding rule before relying on a result. For medication work, use the relevant purpose-built calculator where available and follow local policy and independent-check requirements.
Clinical use and safety
When to use this calculator — and its limits
The arithmetic can be correct while the clinical decision is still wrong. These boundaries show what the calculator can and cannot establish.
When to use
- Use for everyday arithmetic involving addition, subtraction, multiplication, division, percentages and brackets.
- Use for scientific functions including square roots, powers, logarithms and trigonometry in DEG or RAD mode.
- Use as an arithmetic aid while working through a verified formula, such as the square-root step in the Mosteller BSA equation.
Key limitations
- The calculator uses IEEE 754 binary64 JavaScript Number arithmetic. It has roughly 15–17 significant decimal digits depending on magnitude, and exact integer arithmetic is only guaranteed through 9,007,199,254,740,991 (2^53 − 1).
- It evaluates real numbers only; complex numbers, symbolic algebra, matrices, graphing and unit-aware calculations are outside its scope.
- Percent means divide by 100. It does not infer a percentage increase or decrease from context.
- The result is shown with up to 14 significant digits; the required rounding point must come from the problem, standard or protocol.
What MedMaths does not decide
- Which formula, measurement system, clinical pathway, dose limit or conversion factor is appropriate.
- Whether an entered value, operator, unit or angle mode matches the original problem.
- Whether a medication calculation is clinically safe, complete or ready for administration.
Evidence and method checks
- Use the Calculator in Windows — Microsoft Support
- Windows Calculator source and behaviour — Microsoft
- Math — JavaScript reference — MDN Web Docs
- Number — JavaScript reference — MDN Web Docs
- ECMAScript Number Types — ECMA International / TC39
- Error Identification — WCAG 2.2 — W3C
- ARIA in HTML — W3C
Formula logic and known-value examples are checked as part of the MedMaths review process.
See how MedMaths checks calculator methods →BSA square-root example
How to enter the Mosteller BSA equation
The Mosteller equation is BSA = √((height in cm × weight in kg) ÷ 3600). For 170 cm and 70 kg, enter:
sqrt((170 × 70) ÷ 3600)
The unrounded result is approximately 1.818118…, displayed as 1.82 m² when rounded to two decimal places. A general calculator performs the arithmetic; the dedicated BSA tool also handles measurement inputs, formula choice and working.
Open the BSA calculatorScientific calculator functions
A quick guide to the keys, typed equivalents and example results.
Scientific calculator functions
A quick guide to the keys, typed equivalents and example results.
| Key | What it does | Example |
|---|---|---|
| √ or sqrt | Square root | sqrt(144) = 12 |
| x² and xʸ | Square or raise a value to any power | (3 + 2)^2 = 25 |
| sin, cos, tan | Trigonometric functions in the selected angle mode | sin(30) = 0.5 in DEG |
| sin⁻¹, cos⁻¹, tan⁻¹ | Inverse trigonometric functions | asin(0.5) = 30 in DEG |
| log and ln | Base-10 and natural logarithms | log(1000) = 3 |
| π and e | Mathematical constants | 2 × π = 6.283185… |
| % | Divide the preceding value by 100 | 200 × 10% = 20 |
| n! | Factorial for whole numbers from 0 to 170 | 5! = 120 |
| Ans | Reuse the most recent successful answer | Ans ÷ 2 |
Order of operations and brackets
The calculator follows a consistent precedence so a complete expression can be entered at once.
Order of operations and brackets
The calculator follows a consistent precedence so a complete expression can be entered at once.
Why brackets matter
Without brackets, 2 + 3 × 4 = 14. With brackets, (2 + 3) × 4 = 20. When entering a formula, use brackets to mirror the printed fraction, numerator, denominator or power.
Common entry mistakes
- • Leaving a bracket open or placing two operators together.
- • Using DEG mode for a value supplied in radians, or RAD mode for degrees.
- • Rounding an intermediate result before the formula is complete.
- • Entering a logarithm of zero or a negative number in real-number mode.
- • Copying a correct result into the wrong unit or treating a BSA value as a medication dose.
Questions and answers
Scientific calculator FAQ
Continue calculating
Continue with a purpose-built calculator
Use the scientific calculator for arithmetic, then switch to the focused tool when you need formula-specific inputs, units and working.
BSA Calculator
Calculate body surface area from metric or imperial height and weight using four published formulas.
Open calculatormg to mL Calculator
Convert a medicine dose in milligrams to mL using the supplied concentration.
Open calculatormg/kg to mL Dose Calculator
Calculate mg/kg per-dose or per-day orders using kg or lb, divided doses, and liquid concentration.
Open calculatorMedication Dilution Calculator
Solve C1V1=C2V2 for medication stock volume, final total volume, or concentration.
Open calculatorTechnical references
These references describe the browser number and mathematical functions used by the calculator. Formula choice and clinical application require the relevant subject-specific source.
- ECMAScript Language Specification — Number Type
The language specification for JavaScript Number values and IEEE 754 binary floating-point behaviour.
- MDN Web Docs — Number
Practical documentation for binary64 precision, Number.MIN_VALUE and the maximum safe integer boundary.
- MDN Web Docs — Math
Reference documentation for square root, powers, logarithms, trigonometric functions and mathematical constants.
- W3C — WCAG 2.2 Error Identification
Accessibility guidance supporting explicit identification of malformed or unsupported calculator input instead of silently changing it.
- W3C — ARIA in HTML
Semantic and accessible-name guidance used for the calculator's grouped controls and result feedback.
- MedMaths — Mosteller BSA formula and original publication
Subject-specific formula history, published source, worked calculation and limitations for the BSA square-root example.