The Museum of HP Calculators


HP-38C 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-38C
Display type LED
Display format 1 Line
FIXed number format Yes
SCIentific number format Yes
ENGineering number format -
STanDard / ALL number format -
Alpha messages and prompts -
Softkeys labeled by mag. card or overlay -
Softkeys labeled by display menus -
Softkeys with neither labeling system -
Status annunciators -
Redefinable keyboard -
Logic HP-38C
Logic system RPN
Stack levels 4
Last x Yes
Undo -
Precedence -
Parentheses -
Storage Addition (STO +) Yes
Storage Arithmetic (STO +, −, ×, ÷) Yes
Storage Exponentiation (STO ^) -
Recall Arithmetic -
Named variables -
Multiple data types -
Directories -
Math HP-38C
+, −, ×, ÷ Yes 
1/x Yes
Yes
x2 -
LOG x -
10x -
LN x Yes
ex Yes
yx Yes
π -
% 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-38C
Solver / root finder -
Numeric integration -
Complex numbers -
Matrix operations -
Matrix writer -
Equation writer -
Symbolic operations -
Fractions -
Plotting and graphics (display) -
Plotting and graphics (printer / plotter) -
Statistical HP-38C
Mean, standard deviation (# of variables) 2
Σ of n, x, x2 Yes
Σ of n, x, x2, y Yes
Σ of n, x, x2, y, xy Yes
Σ of n, x, x2, y, y2, xy Yes
Σ of lists -
Random number generator -
Linear regression, estimate  Yes
Curve fitting -
Correlation coefficient Yes
Normal distribution -
Factorial Yes
Gamma -
Combinations and permutations -
Scientific and Time HP-38C
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 -
Timer -
Dynamic calculations (timer × rate) -
Alarms -
Unit Conversions HP-38C
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-38C
Number of payments (n) Yes
Interest rate (i) Yes
Present Value (PV) Yes
Payment (PMT) Yes
Future Value (FV) Yes
Cash Flow Analysis HP-38C
Net present value (NPV) Yes
Internal rate of return (IRR) Yes
Amortization HP-38C
Accumulated Interest (ACC INT) Yes
Balance (BAL) Yes
Depreciation HP-38C
Straight line (SL) -
Sum of the years digits (SOYD) -
Declining balance (DB) -
Bonds and calendar functions HP-38C
Bond price -
Bond yield -
Date arithmetic / calendar functions Yes
Memory and Programming HP-38C
Programming language(s) RPN
RAM / Max # of variables or addressable registers 20
Max # of program steps 99
RAM / Max vars or regs with full optional RAM -
Max # of prog steps with full optional RAM -
Merged program steps  Yes
Manual register / program memory allocation  -
Automatic register / program memory allocation Yes
Overlapped register and program memory -
Continuous memory Yes
Flags -
Conditional tests 2
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 Yes
Alpha messages and prompts in programs -
Alpha program listings -
Alpha string manipulation -
Program step insert / delete -
I/O and Expansion Features HP-38C
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 -
Printer -
Networking -
Other -
General HP-38C
Sounds -
Self test Yes
Hard case (in addition to soft case) -
Additional Features -
Batteries Rechargeable
Length (inches) 5.6"
Width 2.8"
Height 1.2"
Weight (oz or lbs) 6-8 oz*
Year of introduction 1979
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-38C notes:
  • Late versions were about 1.5 oz lighter than earlier versions.
  • Self test by pressing STO and then ENTER. At the end of the test, the entire display lights to indicate success.

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