GATE Virtual Calculator: A Complete Guide and Online Practice

GATE virtual calculator practice

A practice copy of the GATE exam's on-screen calculator, with the same results, error messages and quirks. Keep it open while you solve numericals.

Scientific Calculator

M0

Quick help

Type the number first, then press a one-number function: 30 then sin gives 0.5.

For two numbers, press the operation between them and finish with =.

Press an operator before a bracket: 2 * ( 3 + 4 ). A number typed straight before ( is dropped.

+/- changes the sign of the number already on screen, so press it after typing the number.

C clears everything. ← deletes the last digit you typed. After Math Error or Infinity, only C works.

Choose Deg or Rad before any trigonometry. Deg is selected when the calculator opens.

Memory: MS stores the number on screen, M+ and M- add or subtract it, MR recalls it and MC clears it.

The full guide with examples is on this page.

Mouse or tap only. Keyboard typing does nothing here, just like in the exam.

Practice drill

Work out the question on the calculator, then check your answer.

First time? Start here

GATE does not allow physical calculators; you calculate on screen with the mouse. Check the current GATE information brochure for the exact rules.

The exam calculator is operated with the mouse only, and so is this copy. Every key sequence on this page has a Play button that presses the keys on the calculator for you, so you can watch exactly what happens.

The rule that trips people up: for a one-number function such as sin, log, x² or √, type the number first and then press the function.

gives 0.5

Pressing sin before typing 30 will not give you sin 30.

For an operation that needs two numbers, press its key between the numbers and finish with =.

gives 1024

Two habits save marks: press C before every new calculation, and check Deg or Rad before any trigonometry.

Reading the display

The lower line shows the number you are typing or the latest result. The upper line is a record of the calculation, written with the calculator's own names. A small M at the left of the lower line means memory holds a value.

Results that don't round cleanly are shown with every digit the computer holds:

gives 1.5707963267948966

What the upper line means

sindsinr

sin in Deg or in Rad. cos, tan and the inverses follow the same pattern: cosd, tanr, asind.

sinhdsinh-1d

sinh and sinh^-1. Hyperbolic keys get a d or r too, although Deg and Rad don't change them.

sqrcube

x² and x³

sqrtcuberoot

√ and ∛

reciproc

1/x

absfact

|x| and n!

powepowten

e^x and 10^x

logXbase2

log₂x

^yroot

x^y and ^y√x

logxBasey

log_yx

e+3e-19

Exp, with a positive or negative power

Error messages

Math Error

An impossible trig or factorial calculation, such as tan 90°, sin^-1 of a number above 1, or the factorial of a negative number.

gives Math Error

Infinity

Division by zero, the log of 0 (shown as -Infinity), or a result too large to hold, such as 171!.

gives Infinity

NaN

Short for "not a number": an invalid input such as the square root of a negative number.

gives NaN

After Math Error or Infinity every key except C stops working, so press C and start again. After NaN you can type a new number, but pressing C is still the safer habit.

Things that catch people out

These come straight from how the exam calculator works. Each one is easy to avoid once you have seen it happen.

Pressing +/- before the number

+/- changes the sign of the number already on screen, so press it after typing the number.

gives -15

gives 15

In the second sequence, +/- turned the 5 still on screen into -5, and typing 3 then replaced it.

No operator before a bracket

A number typed straight before ( is dropped. Always press an operator first.

gives 7

gives 14

Chained powers

Repeated x^y is worked out from left to right, so 2^3^2 means (2³)². Use brackets when you mean 2 to the power 3².

gives 64

gives 512

A power between ÷ and ×

Typed in one go, 2 ÷ 3^2 × 4 is worked out as 2 ÷ (3² × 4), which is not what you want. Put the power in brackets, or use x² for a square.

gives 0.05555555555555555

gives 0.8888888888888888

gives 0.8888888888888888

Whenever a calculation mixes powers or roots with × and ÷, brackets make the order certain.

Numbers longer than 9 characters

A typed number can have at most 9 characters, counting the decimal point and minus sign. Extra digits are ignored without any warning, so watch the lower line when you type long constants.

gives 123456789

Very small and very large results

Results smaller than 0.00000001 or larger than 100,000,000 are shown exactly as the computer stores them, so floating-point noise can appear in the last digits.

gives 1.6000000000000002e-19

Read it as 1.6 × 10^-19.

A messy upper line

After brackets and functions, the upper line sometimes shows leftovers such as (sqr(3.2)+sqrsqrt(41.6). It is only a record; the lower line holds the value that counts.

What every key does

Clearing and editing

Clears the whole calculation; memory is kept. It is the only key that works after Math Error or Infinity.

Deletes the last digit of the number you are typing.

gives 123

Changes the sign of the number on screen. Type the number first.

gives -25

Arithmetic and brackets

Add, subtract, multiply, divide. Multiplication and division are done before addition and subtraction.

gives 14

Group part of a calculation. Press an operator before ( and close every bracket you open.

gives 20

Remainder after division.

gives 2

a % b gives b percent of a.

gives 30

Powers and roots

Square or cube the number on screen.

gives 144

x to the power y. The first number is x, the second is y.

gives 1.79585632602213

Square root and cube root of the number on screen. ∛ works on negative numbers; √ of a negative number gives NaN.

gives -3

The y-th root of x. Type x, press this key, type y, press =.

gives 2

Reciprocal and absolute value of the number on screen.

gives 0.125

Logs and exponentials

Logarithm to base 10, base e and base 2.

gives 3

Logarithm of x to any base y. Type x, press this key, type the base, press =.

gives 4

e or 10 raised to the number on screen.

gives 100

Powers of ten: 2.5 Exp 3 means 2.5 × 10³. For a negative power, type the power and then press +/-.

gives 2500

Trigonometry

The angle unit for sin, cos, tan and their inverses. Deg is selected when the calculator opens. Choose the unit before you start, not halfway through.

Type the angle, then press the function. tan 90° gives Math Error.

gives 0.5

Inverse functions; the answer comes out in the selected unit. sin^-1 or cos^-1 of a number outside -1 to 1 gives Math Error.

gives 45

Hyperbolic functions

Hyperbolic functions and their inverses. Deg and Rad do not affect them.

gives 1.1752011936438014

Constants and factorial

Put the full value of π or e on screen, then use it like a typed number.

gives 6.283185307179586

Factorial of the number on screen. Decimals work too; negative numbers give Math Error and anything above 170 gives Infinity.

gives 120

gives 0.8862269254527586

Memory

Stores the number on screen, replacing whatever was in memory.

Adds the number on screen to memory, or subtracts it.

Brings the stored number back onto the screen.

Empties memory. The M on the display disappears.

Running total of 12.5 × 3 + 7.2 × 4: gives 66.3

Worked examples

These are the kinds of numbers that come up in GATE numericals. Press Play to watch, then try the same keys yourself.

Combinations: ¹⁰C₃ = 10! / (3! × 7!)

gives 120

The brackets keep 3! × 7! together as the denominator.

Magnitude: √(3.2² + 5.6²)

gives 6.44980619863884

Press = to get 41.6 first; √ then acts on that result.

Scientific notation: (6.022 × 10²³) × (1.6 × 10^-19)

gives 96352

Same keys, different unit

In Deg: gives 0.5

In Rad: gives -0.9880316240928618

A wrong angle unit gives a confident, wrong answer. Switch back to Deg when you are done.

Exponential decay: e^-0.25

gives 0.7788007830714049

Do's and don'ts

Do

• Press C before starting a new calculation.
• Set Deg or Rad before any trigonometry.
• Type the number first, then press +/- or a function.
• Press an operator before every bracket.
• Add brackets when powers or roots are mixed with × and ÷.
• Use memory (MS, M+, MR) for running totals instead of re-typing numbers.

Don't

• Change Deg or Rad in the middle of a calculation.
• Leave brackets unbalanced.
• Type numbers longer than 9 characters.
• Read your answer from the upper line; the lower line holds the value.

Several of these also appear in the official calculator's own Help panel.

Limits listed by the official calculator

The Help panel built into the official calculator lists these limitations:

• Keyboard input is disabled; use the mouse.
• Factorial results are precise up to 14 digits.
• Logarithmic and hyperbolic results are precise up to 5 digits, so don't rely on digits beyond that.
• mod on decimal numbers with about 15 digits is not precise; it works best on smaller numbers.
• The supported range is roughly 10^-323 to 10³⁰⁸.

About this practice calculator

This is an independent practice copy, not the official software, and it is not affiliated with GATE, IISc or the IITs.

Its calculation logic follows the official calculator's script. It was tested key for key against public copies of that script, including the results, rounding, error messages and quirks described above. The exam version could still change, so try the official mock test on the GATE website before exam day.