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CALC 1 User Guide for HP 10bII+ Users

CALC 1 has a HP 10bii reproduction. This page is a guide to the features of CALC 1 from a 10bii users perspective.

  1. All of the financial calculations (TVM, Bonds, Cash Flows, Depreciation, Amortization) has separate calculators so the important keys are on the top row.
  2. There are form calculators that have easier input (date pickers, ...) and full tables of results for the amortization and depreciation calculations.
  3. There are separate statistics calculators so the important keys are at the top and more function.
  4. CALC 1 has Key Preview for TVM , STO/RCL and Formula Calculators.
  5. Undo is available to recover from mistakes.
  6. A List Manager to review and edit the values for statistics and cash flows.
  7. Currency and UOM conversions.
  8. Many Formula Calculators with solving (enter any two values to calculate the third value) and graphing.
  9. A History List to quickly recall past calculations.
  10. Customization without programming.

At the bottom of the page are tables of detailed features.

TVM Calculations

The default "Financial: TVM I/YR" Focused Calculator is similar to the HP 10bii. The Auto STO "AS" annunciator will turn on when you have entered a number to let you know that then number will be stored when you tap the N, I/YR, PV, FV keys. Otherwise the value will be calculated. If there is any question, hold the key down and the hint will tell you if you are storing or calculating.

This calculator has P/YR and C/YR (compounding periods). The C/YR is set to the P/YR value when you store it and is not cleared when you tap "clr f".

Arithmetic Calculations

CALC 1 supports chain (CHN), algebraic (ALG) and Reverse Polish Notation (RPN) calculation methods. See Calculation Methods Used by CALC 1 for an overview of each system.

CALC 1 default chain mode is similar to the chain mode on the HP 10bii except CALC 1 will display the first number and the operator instead of the "PEND" annunciator.

Clearing the Calculator

When enter a new number, the "del" key will erase the last digit entered. The "del" key will clear an entered number.

Clearing Messages

Tap the "del" key to clear error messages.

Clearing Memory

Each Focused Calculator will have keys for clearing that you see when you tap the "shift" key". They typically are:

"clr x" to clear the x register (the bottom number in the display.

"clr s" tap clear the stack.

"clr m" to clear the user memory variables, a-z.


Instead of a single line, 7 segment display, CALC 1 has a flexible display that takes advantage of the high resolution iOS retina display. The CALC 1 display area can display 1 to 4 lines of values, key hints, and error messages (not error codes that you need to look up in the manual). The top line of the display shows the name of the current calculator. There are also two mode settings that will be displayed when they are not in the default mode. For the trig degree mode the default is radians so you will only see the mode indicator set when the trig mode is degrees. The time value of money end mode is the default and when in begin mode, the BEGIN status is displayed.

CALC 1 will display a hint when you press and hold a key. So CALC 1 does not need all of the hard wired annunciators that a hardware calculator needs.

Shift Key

CALC 1 has one shift key. The STO and RCL keys also give the keys alternate functionality and are usually reserved for storing and recalling values as opposed to computing them. Pressing shift a second time will cancel the shift mode. Cancel STO or RCL by tapping a key without a label.

Note that you can press and hold a key to display a hint for that key. Dragging your finger off of the key will prevent the key function from being executed. If you mistakenly tap a key, CALC 1 has undo support.

Statistics Key

CALC 1 has separate statistics Focused Calculators instead of a statistics shift key since it performs many more statistical calculations.


Use the = or ENTER key between numbers to put a number in the stack for two number operations like Δ%.


The CALC 1 SWAP key is used to swap the x and y registers in the stack. Since CALC 1 can display two or more values, the SWAP key is not needed to view the results of functions that return two values.

CALC 1 also has a ROLL key to roll the automatic stack to use previous results in a chain calculation.

Math Functions

CALC 1 has many math functions for each Focused Calculator. See the help page for the calculator. Two number functions are similar for CALC 1 except you can use ENTER key instead of the INPUT key.

Display Format of Numbers

CALC 1 display options can be set in the Options view. You have the 3 number styles (None, Decimal and Scientific), the number of digits and rows to display. CALC 1 also has an option to use significant digits.

The number of digits can also be adjusted using the iOS pinch gesture. The number of rows can be changed by swiping up and down on the display.

On many calculators there is a "DEC x" to set the number of decimal places. You key in the number of decimal places then tap the "DEC x" key.

See the CALC 1 User Guide for links to videos on gestures.

There is no need for a setting for interchanging periods and commas. This setting is handled automatically and is determined by the region setting on your device.

Rounding Numbers

CALC 1 has RND keys on many of the calculators to round to the number of digits displayed. Some financial calculators also have the RND(2) key to round to 2 places regardless of the number of decimal places displayed. If the RND key is not on a Focused Calculator that you use, you can copy and paste the key to that calculator.

Business Percentages

See the page on CALC 1 Percentage Calculation Keys for calculating percentages.

CALC 1 also has the following Formula Calculators for percentage calculations:

Margin and Markup Calculations

CALC 1 has the following Formula Calculators for margin and markup calculations:

Number Storage and Arithmetic

CALC 1 uses the "ra" register arithmetic for both repetitive adding, subtracting, multiplying and dividing.

The Math: General calculator has the "+ tax" key for repetitive percentage calculations (sales tax, tips, ...)

The Math: General calculator has RM. M+, M- CM and M% (percent of M) keys to store, recall and sum numbers using the

CALC 1 uses a-z variables for user memory instead of numbered registers.

Financial Solutions

CALC 1 has the following calculators for the financial solutions found on the HP 10bII:


HP 10bII CALC 1 Comments
Time Value of Money

Financial Time Value of Money I/YR Calculator

Time Value of Money Form Calculator

Compounding periods can also be set for cases where the payments and compounding periods differ.

Financial Amortization Calculator

Amortization Form Calculator.

The Financial Amortization Calculator allows to to set the starting and ending period and has a key to advance to the next periods. There is also no need to reset the "N" or "PV" values if you want to go out of order. The calculations for each set of periods are save in the CALC 1 History.

Markup and Margin Markup as Percent of Cost
Markup as Percent of Price
Interest Conversion Effective Interest Rate Formula Calculator  
Cash Flows Financial Cash Flows Calculator In addition to IRR and NPR, CALC 1 calculates MIRR. Up to 1,000 cash flows that can be easily edited and re-ordered using the List Manager.
Statistics Statistics: 1 List Calculator
Statistics: 2 List Calculator
List based statistics for 1 & 2 lists. Up to 1,000 cash flows that can be easily edited using the List Manager. List based statistics can calculate median, min, max that cannot be calculated with calculators that aggregate their statistics.

CALC 1 has the following calculators for the financial solutions not found on the HP 10bII (some are on the HP10bii+)

  CALC 1 Comments

Financial Bonds Calculator

Bonds Form Calculator

CALC 1 has 5 different date basis and 3 frequencies.

Financial Depreciation Calculator

Depreciation Form Calculator.

SL, SOYD, DB and DBX with starting month calculations.
Curve Fitting Curve Fitting: LIN Calculator
Curve Fitting: Ln Calculator
Curve Fitting: EXP Calculator
Curve Fitting: PWR Calculator
Separate calculators for each type of curve fitting. (Linear curve fitting is included with the HP 10bII)
Interest Conversion Effective Interest Rate Formula Calculator  
Profit Margin Profit Margin Formula Calculator  
Breakeven Breakeven Formula Calculator  

Dates Form Calculator

DAYS Function Formula Calculator

DAYS360 Function Formula Calculator

The TVM and Bond Calculators have date keys for quick date calculations.
Currency Conversions Currency Conversions Form Calculator This performs conversions from any Focused or Formula calculator by tapping the CALC 1 logo.
Conversions Conversions Form Calculator This performs conversions from any Focused or Formula calculator by tapping the CALC 1 logo.
Customization Customization
  1. Copy and paste keys to customize a calculator. Rearrange keys on a calculator or copy them from another calculator.
  2. Create new keys to have your own 1-key solution using the Key Editor. Also modify existing keys or view the formulas.
  3. Create your own formula calculator that focuses on a single formula.