Numbers & operators.
Type like you think. The result line previews the answer as you build the expression — equals only commits it. Operator mistakes overwrite themselves: press + then × and the × replaces it.
12×(3+4) = 84
01
The instrument.
No account, no install, no telemetry — the whole instrument is this page. The big line previews live as you type; equals simply commits what you already see. Click anything on the tape to reload it.
M
0
0
SWS-SC/01·30+ FUNCTIONS·DEG & RAD·4-KEY MEMORY·0 TRACKING
02
How to use it.
Ninety seconds to full fluency. The notation is standard — if you can write the expression, the calculator can evaluate it.
Trig, in degrees or radians.
DEG is the default — the mode most geometry and everyday trig lives in. Switch to RAD for calculus and physics. The toggle sits top-left of the pad, and the preview updates instantly when you flip it.
DEG: sin(30) = 0.5 · RAD: sin(π÷6) = 0.5
The 2ND key.
Tap 2ND to flip the pad to its second layer: sin becomes sin⁻¹, ln becomes eˣ, log becomes 10ˣ, x² becomes x³, √ becomes ∛ and xʸ becomes x⁻¹. Tap again to flip back — active keys glow amber.
2ND → sin⁻¹(0.5) = 30
Powers, roots, E-notation.
xʸ raises to any exponent, x! computes factorials up to 170!, and EXP writes scientific notation the way a physicist reads it. The ± key flips signs, including inside exponents.
6.022E23 · 5! = 120 · 2^10 = 1024
π, e, Ans & memory.
Constants are one tap away. Ans recalls the last committed result so you can chain calculations. M+, M−, MR and MC are a real four-key memory register — the M badge lights up when something is stored.
2π = 6.28318530718
Keyboard-first.
The whole pad is mapped to your physical keys — digits, operators, ^, parentheses, Enter, Backspace and Esc, plus p for π, e for e and a for Ans. The full map sits just below these steps.
ENTER = equals · BACKSPACE = ⌫ · ESC = C
studywithstem:keyboard
12 BINDINGS
0–9 · .digits & decimal
+ − * /operators
xmultiply
^power
( )parentheses
Enter · =equals
Backspacedelete last
Esc · Deleteclear all
pπ
eeuler's e
alast answer
! · %factorial · percent
ALL LOCAL · NOTHING LOGGED
03
Frequently asked.
The questions that keep coming back about this tool — answered once, in full.
Q1 Is this scientific calculator really free?
Yes — completely. No accounts, no limits, no locked functions. Every key works from the first tap. The calculator is part of StudyWithSTEM's free tools collection, supported by our posters and memberships — never by your data.
Q2 Does my input ever leave my device?
No. Every computation runs locally in your browser's JavaScript engine. Nothing you type is recorded, transmitted or stored — and once the page has loaded, it keeps computing even when you go offline.
Q3 What's the difference between DEG and RAD?
They're two units for angles. Degrees split a circle into 360 parts; radians measure angles with π — a full circle is 2π radians. Use DEG for geometry, navigation and everyday trigonometry; use RAD for calculus and physics, where formulas like sin(x) ≈ x only hold in radians. Same keystrokes, different angle: sin(30) is 0.5 in DEG mode, while 30 radians is a completely different angle (result ≈ −0.988).
Q4 How do I compute inverse trig functions like arcsin?
Tap the 2ND key — the pad flips to its second layer: sin becomes sin⁻¹, cos becomes cos⁻¹ and tan becomes tan⁻¹. The same layer also unlocks eˣ, 10ˣ, x³, ∛ and x⁻¹. Tap 2ND again to flip back. Example: 2ND → sin⁻¹(0.5) → 30 in DEG mode.
Q5 How does the percentage key work?
The % key is a postfix operator that converts a percentage to its decimal form: 50% becomes 0.5, so 200×50% equals 100. To add 20% to a value, multiply by 1.2 — or use parentheses: 200 + (20%×200) = 240. It's the honest, unambiguous reading of the symbol.
Q6 Why does 0.1 + 0.2 display as 0.3?
Because we clean up after binary floating point. Computers store decimals in base 2, and 0.1 + 0.2 is actually 0.30000000000000004 at the hardware level. The display rounds to 12 significant digits, while the underlying math stays full IEEE-754 double precision — the same standard handheld calculators only approximate.
Q7 What's the largest factorial it can compute?
170! ≈ 7.257×10³⁰⁶ — the biggest factorial that fits in a double-precision float. Anything larger overflows to ∞. Factorials only accept non-negative whole numbers, and 0! = 1, as it should be.