The Museum of HP Calculators

HP-18C Features

Features in optional ROMs are listed as Option.
Features in HP mag card or tape Application Pacs are listed as +.
Other software is not included.
Display and Keyboard HP-18C
Display type LCD
Display format 4 Line
FIXed number format Yes
SCIentific number format -
ENGineering number format -
STanDard / ALL number format Yes
Alpha messages and prompts Yes
Softkeys labeled by mag. card or overlay -
Softkeys labeled by display menus Yes
Softkeys with neither labeling system -
Status annunciators Yes
Redefinable keyboard -
Logic HP-18C
Logic system Algebraic
Stack levels 4
Last x Yes*
Undo -
Precedence -*
Parentheses Yes
Storage Addition (STO +) Yes
Storage Arithmetic (STO +, −, ×, ÷) Yes
Storage Exponentiation (STO ^) Yes
Recall Arithmetic -
Named variables -
Multiple data types -
Directories -
Math HP-18C
+, −, ×, ÷ Yes 
1/x Yes
x2 Yes
LOG x Yes
10x Yes
LN x Yes
ex Yes
yx Yes
π Yes
% Yes
% change Yes
INTeger truncation and ABSolute value Yes
Trigonometric functions (SIN, COS etc.) -
Hyperbolic trig. (SINH, COSH etc.) -
# of trig. modes (degrees, radians, grads) -
Advanced Math HP-18C
Solver / root finder Yes
Numeric integration -
Complex numbers -
Matrix operations -
Matrix writer -
Equation writer -
Symbolic operations -
Fractions -
Plotting and graphics (display) -
Plotting and graphics (printer / plotter) -
Statistical HP-18C
Mean, standard deviation (# of variables) 1
Σ of n, x, x2 -
Σ of n, x, x2, y -
Σ of n, x, x2, y, xy -
Σ of n, x, x2, y, y2, xy -
Σ of lists Yes
Random number generator -
Linear regression, estimate  Yes
Curve fitting Yes
Correlation coefficient Yes
Normal distribution -
Factorial Yes
Gamma -
Combinations and permutations -
Scientific and Time HP-18C
Polar / rectangular conversions -
Base conversions (2, 8, 10, 16) -
Arithmetic in bases 2, 8 and 16 -
Bit operations (AND, OR, XOR, ...) -
Selectable word size (1-64 bits) -
Selectable complement mode (1's, 2's, unsigned) -
Decimal hrs / hrs.min.sec. conversions -
Hrs.min.sec arithmetic -
Time of day clock Yes
Timer -
Dynamic calculations (timer × rate) -
Alarms Yes
Unit Conversions HP-18C
Centimeters / inches -
Millimeters / inches -
Meters / feet -
Kilograms / pounds (mass) -
Newtons / pounds (force) -
British thermal units / joules -
Liters / gallons -
° Celsius / ° Fahrenheit -
Other -
User-defined units -
Time Value of Money HP-18C
Number of payments (n) Yes
Interest rate (i) Yes
Present Value (PV) Yes
Payment (PMT) Yes
Future Value (FV) Yes
Cash Flow Analysis HP-18C
Net present value (NPV) Yes
Internal rate of return (IRR) Yes
Amortization HP-18C
Accumulated Interest (ACC INT) Yes
Balance (BAL) Yes
Depreciation HP-18C
Straight line (SL) -
Sum of the years digits (SOYD) -
Declining balance (DB) -
Bonds and calendar functions HP-18C
Bond price -
Bond yield -
Date arithmetic / calendar functions Yes
Memory and Programming HP-18C
Programming language(s) -*
RAM / Max # of variables or addressable registers 1200 bytes /
4 registers
Max # of program steps -
RAM / Max vars or regs with full optional RAM -
Max # of prog steps with full optional RAM -
Merged program steps  -
Manual register / program memory allocation  -
Automatic register / program memory allocation -
Overlapped register and program memory -
Continuous memory Yes
Flags -
Conditional tests -
Subroutine levels -
Indexed looping (increment by +/- 1, end at 0) -
Indexed looping (choice of increment and end) -
Multiple index / loop registers -
Line number addressing -
Branching by relative line number -
Global program label addressing -
Local program label addressing -
Indirect / computed addressing and control -
Multiple indirection registers -
Pause -
Alpha messages and prompts in programs -
Alpha program listings -
Alpha string manipulation -
Program step insert / delete -
I/O and Expansion Features HP-18C
ROM modules -
RAM modules or expansion option -
General expansion slots / connector -
Magnetic card reader/writer -
Tape drive -
Disk drive -
Upgradeable firmware -
Optical wand -
Serial port -
Infrared input -
Infrared output Yes
Printer Option
Networking -
Other -
General HP-18C
Sounds Yes
Self test Yes
Hard case (in addition to soft case) -
Additional Features -
Batteries 3 N cells
Length (inches) 6.2"
Width 3.75"
Height 0.7"
Weight (oz or lbs) 8oz
Year of introduction 1986
Features in optional ROMs are listed as Option.
Features in HP mag card or tape Application Pacs are listed as +.
Other software is not included.

Unlim means limited only by available memory.
HP-18C notes:
  • The calculator didn't have precedence but the solver did.
  • The Solver allowed conditional expressions which effectively provided limited programmability.
  • LAST retrieved value from history stack.
  • Press and hold ON and press the fourth menu key from the left. The calculator will beep and display a series of vertical bars. You can now press any key to step through a series of tests (each with a different display - one blank.) Once the calculator displays KEYBOARD TEST, you must press each key on the alpha (left) keyboard starting from the upper left and proceeding from left to right and then down. You will hear a beep on each keystroke. After the alpha keyboard, do the same with the main (right) keyboard. When you are finished, you will see: OK-18C-E. The message FAIL will be displayed if there is a problem or if you press keys in the wrong order. By pressing and holding ON and pressing the fifth menu key, you can put the calculator into a continuous self-test (minus the keyboard test.) To exit the continuous test press and hold ON and press the third menu key.

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