00:00:00

← Return

Calduo

Calduo lets you save a useful result as a card beside the calculator, so you can refer to it while working out the next estimate. Tax and percent controls can be switched on or off when you need them.

Just type

  1. Open the CALC tab and type your expression straight from the keyboard
  2. Press Enter or = to confirm
  3. The answer swells for a moment to tell you it's final

What you can use:

  • Digits and a decimal point
  • + - * / (* and / become × and ÷ automatically)
  • Brackets ( ) and { }
  • Backspace — delete one character
  • ← → — move the cursor
  • Escape — clear everything

Long expressions wrap onto the next line by themselves.

There's a keypad too

  • The TenKey button below the card opens a keypad
  • Everything works with the mouse alone
  • Whether it's open or closed is remembered. Keep it shut if you never use it; keep it open if you do

How it calculates

  • Standard order of operations (× and ÷ before + and −; for example 2+3×4 = 14)
  • Two kinds of brackets, ( ) and { }. Match each kind with itself and nest them however you like (e.g. {(120+80)×3}÷2)
  • Negative numbers work as written (e.g. -5+3, 2×(-3))
  • The answer updates as you type; while an expression is incomplete, the last valid answer stays on screen
  • Dividing by zero, or confirming an incomplete expression, shows a small Error where the answer goes (it disappears with your next keystroke)

Precision

  • Answers are shown to 12 significant digits; anything beyond that is trimmed with "..."
  • Trailing zeros are dropped (2.500 → 2.5)
  • The value you copy is rounded to 12 significant digits, with no thousands separators
  • Floating-point quirks such as 0.1 + 0.2 are corrected internally, so you get 0.3

TAX+ / TAX− / % — compare, don't recalculate

Three modifiers you can switch on and off as often as you like.

  • TAX+ — adds tax. At a rate of 10, that's answer × 1.1
  • TAX− — works backwards from a tax-included figure to the base price. At a rate of 10, that's answer ÷ 1.1 (not a subtraction)
  • % — takes n% of the answer. 50 halves it; 150 makes it 1.5×

How to use them:

  1. Click a pill: it fills in, and a field opens on its right
  2. Type a number — the answer updates as you type
  3. Click the pill again and the answer returns to normal (your number is kept)

Notes

  • The order of application is TAX → %
  • TAX+ and TAX− cannot both be on. % can be combined with either
  • Values can go up to 999.9, decimals included
  • Whatever is currently applied is shown in small text under the answer (e.g. TAX+10 · %5)
  • Your rates are remembered, but the pills always start switched off. A calculator is for more than tax

Keeping a calculation as a card

The generate button saves the current expression and answer to the right.

  • Each card records the expression, the answer, and the TAX/% that were applied
  • Use the pencil icon to give it a name — a client, a project, whatever helps
  • Use the copy icon to copy just the answer (rounded to 12 significant digits)
  • Click a card to load the expression back into the editor, along with its TAX/% state, and carry on. The selected card is shown with a thicker border
  • Use the trash icon to delete it