Learn how to use Time & Date Calculator

This page walks through every main feature of the Android app: which tab to open, what each button and control does, and how history, records, and Premium options behave. Minor labels may change slightly between app versions—if something looks different on your phone, use the on-screen text as the final word.

For the iPhone / iPad edition (different tab layout and extra tools), see Learn — Time & Date Calc - Aviation (iOS).

On this page

Home screen & bottom navigation

  1. From your device, open the app Time & Date Calculator.
  2. At the bottom of the screen you will see four destinations. Tap one to switch the whole “home” area:
    • Time Calculators — opens a scrollable list of three tools in this order: Smart Time Calculator, Aviation Forecast, and Fuel Calculator.
    • Date Tools — opens a list of Date Calculator, Date Difference, Age Calculator, and Workdays Calculator.
    • Utilities — opens standard Calculator (arithmetic), Time Zone Converter, Countdown Timer, and Expense Splitter.
    • Settings — opens preferences, Premium entry, feedback, licenses, and related options.
  3. Inside a tab, each tool is a row with a title, short subtitle, and a chevron (arrow) on the right. Tap anywhere on that row to open the tool.
  4. To go back from a tool to the list, use the Back gesture or the system Back button. You stay inside the same bottom tab until you switch tabs.
  5. At the top, the title bar shows the name of the current screen (for example “Aviation Forecast” or “Date Calculator”). On many tools you will also see icons on the right—history, overflow (⋮), or actions specific to that screen. Those are explained under each feature below.

Time Calculators tab — what the list shows

After you tap Time Calculators on the bottom bar, you should see three entries in this order (same as in the app):

  1. Smart Time Calculator — subtitle describes add, subtract, multiply & divide time.
  2. Aviation Forecast — subtitle describes forecasting component life & dates.
  3. Fuel Calculator — subtitle describes trip fuel, reserves, and average burn.

Tap the row you need; the sections below follow that list: Smart Time, then Aviation Forecast, then Fuel Calculator. The arithmetic Calculator is under Utilities (see below).

Smart Time Calculator

Open the screen

  1. Tap Time Calculators → Smart Time Calculator (first row in the list).

Top toolbar icons (left to right)

Below the title bar, a row of icon buttons typically includes:

  • Delete (clear) — clears the current calculation / display so you can start fresh.
  • Create Record — opens a flow to save the current work into a Record (grouped entry) when you use that feature.
  • History — opens Smart Time Calculator history (past expressions and results). From history you may open an item or use Edit where Premium allows reloading into the calculator.
  • Backspace — removes the last input step, like a traditional calculator.

Overflow menu (⋮) — layout (Premium)

  1. Tap ⋮ (three vertical dots) in the top bar.
  2. You will see layout options. Basic layout focuses on addition and subtraction of time. Full layout adds multiplication and division for time.
  3. If you are on the free tier, switching to Full layout may show an Unlock Premium dialog; Premium users can toggle the switch directly.

Keypad — digits and operations

  • Tap digits 0–9 to build time values as prompted by the display.
  • In Basic layout, use the minus and plus icons for subtraction and addition operations.
  • In Full layout (Premium), additional operator buttons appear for multiplication and division.
  • Tap = (equals) to complete the calculation. A valid result is typically saved into history automatically when the app is configured to do so.

Records screen (optional)

If you use Create Record, follow the sheet or dialog: enter the details requested, then confirm. You can open Records from navigation where the app provides it (often alongside History) to browse saved record groups.

Aviation Forecast — Time mode & Date mode

Open the screen

  1. Tap Time Calculators → Aviation Forecast (second row in the list).

Switch between Time and Date

  1. Near the top of the screen you will see a segmented control with two choices: Time and Date.
  2. Tap Time for hour-based (AF/ENG style) forecasting.
  3. Tap Date for calendar-based due dates and life remaining.

Time mode — fields, keypad, and Calculate

  1. Time-sensitive fields open a custom time keypad (bottom sheet or overlay) when tapped—use it instead of the phone’s normal keyboard.
  2. Fill in the values labeled on your device (for example current AF/ENG hours, life expired, installed-at hours, inspection/servicing due at AF/ENG hours—wording follows your build).
  3. If shown, enter optional Component name and Tag so history entries are easy to recognize later.
  4. Tap the main action button Calculate (or equivalent primary button) to run the forecast.
  5. Read the result block on screen (e.g. current component hours, life remaining, due-at-hour figures—exact labels match the app).
  6. To see past runs: tap the History icon in the top app bar (if present) to open Time Forecast history. From there you can open an entry or use edit/export actions your version provides.

Date mode — base date, interval, and Calculate

  1. Choose Manufacture date or Installed date using the on-screen selector (radio or chips—tap the option that matches your scenario).
  2. Set the base date using the date control (tap the field or calendar icon to open the date picker; confirm with OK where applicable).
  3. Enter the inspection/servicing interval as a number (decimals allowed) and pick the unit: Years, Months, Weeks, or Days.
  4. Add optional component name and tag if the form shows them.
  5. Tap Calculate to see the due date and life remaining (years, months, days as shown).
  6. Use the app bar History entry for Date forecast history when you need previous calculations. Time and Date histories are kept separately.

Fuel Calculator

Planning aid only—follow your operator, regulator, and approved flight-planning requirements.

Open the screen

  1. Tap Time Calculators → Fuel Calculator (third row in the list).

Choose Pilot or Engineer / ground mode

  1. Use the segmented control (or tabs) at the top to switch Pilot (trip planning from flow and time) and Engineer (average burn from total fuel and time)—labels match your build.

Pilot mode — typical flow

  1. Select a flow unit (litres per hour, US gallons per hour, etc.) so cruise flow and fuel quantities stay consistent.
  2. Enter cruise fuel flow and trip time using the custom time or numeric keypads when a field opens a bottom sheet.
  3. Set contingency from presets (such as 0%, 3%, 5%, 10%, 15%) or switch to a custom percentage.
  4. Pick a final reserve rule: day VFR, night VFR, IFR, or a custom minute value.
  5. For alternate, choose whether you enter extra fuel as a volume or as time at cruise flow.
  6. Add taxi and extra fuel if your checklist includes them.
  7. Optionally type flight number and route for your records.
  8. Tap Calculate. Read trip fuel, contingency, reserve, alternate, and total; review any on-screen disclaimer.
  9. Open History from the app bar when you need prior runs.

Engineer / ground mode

  1. Enter total fuel in the selected quantity unit.
  2. Enter flight or block time.
  3. Add optional aircraft text if the field is shown.
  4. Tap Calculate to read average burn rate in your flow unit.

Date Tools tab

Open Date Tools on the bottom bar, then choose one of the four rows below.

Date Calculator

  1. Tap Date Calculator.
  2. Under Select Date, tap the Date field or the calendar icon on the right. A Date picker opens; choose a date and confirm with OK if shown.
  3. Under Time Units, tap Years, Months, Weeks, or Days. A numeric keypad bottom sheet appears: enter digits, use backspace or reset as offered, then use Next to move to the next field until you dismiss the sheet.
  4. Tap the trash / clear icon in the Time Units card header to Clear All unit fields at once.
  5. Use the segmented control Add / Subtract to choose whether to move the start date forward or backward in time.
  6. The Result card shows the new date in large text. It updates when your inputs are valid.
  7. Tap Save on the Result card to store a named snapshot; a dialog asks for a Name—enter it and confirm Save (subject to free/Premium limits).
  8. Open history from the top bar when the history icon is shown to review past date calculations.

Date Difference

  1. Tap Date Difference.
  2. Start Date — tap the date field or calendar icon to pick the start.
  3. End Date — same for the end (the app may adjust if start and end would be identical).
  4. If your build shows Include time, use the Switch to include time-of-day; then use the time fields and clock icons for Start and End.
  5. The difference updates as you change inputs (no separate “Calculate” on many builds).
  6. Use Save or history actions when visible to keep or recall results.

Age Calculator

  1. Tap Age Calculator.
  2. You start on a Dashboard that lists saved people or birthdays (if you have created any).
  3. Use the in-screen control (often a + button or “add” action) to open Create: enter a name and birth date via the date picker, then save.
  4. Tap a person to open Detail view: see age in years, months, and days relative to a reference date, and any milestone or extra panels your version provides.
  5. Use Back to return to the dashboard; the top title may change between “Age Calculator” and context-specific titles.
  6. History from the app bar opens Age Calculator history when that route is available from the current context.

Workdays Calculator

  1. Tap Workdays Calculator.
  2. Start Date — tap the field or calendar icon; optional presets may appear in a dropdown to jump to common dates.
  3. End Date — same.
  4. Configure exclude weekends and any excluded weekdays or holidays your screen shows (switches, lists, or add-holiday buttons—follow on-screen labels).
  5. Scroll to the result section; the count of workdays updates when inputs are valid.
  6. Use Save or history if shown to store or revisit results.

Utilities tab

Open Utilities on the bottom bar. You should see four tools in this order: Calculator (arithmetic), Time Zone Converter, Countdown Timer, and Expense Splitter.

Calculator (standard arithmetic)

  1. Tap Utilities → Calculator (first row in the list).
  2. Toolbar matches Smart Time patterns: clear, Create Record, History, Backspace.
  3. Use %, parentheses, and standard operators on the keypad; the expression and result lines update as you build the calculation.
  4. This screen is for plain numbers only—use Smart Time Calculator for hour/minute math.

Time Zone Converter

  1. Tap Utilities → Time Zone Converter.
  2. From Time Zone — tap the trailing calendar/zone icon to open the source zone picker; select a region.
  3. Tap the centered Swap icon button to exchange “from” and “to” zones instantly.
  4. To Time Zone — use the trailing icon to pick the target zone.
  5. Under Date & Time, toggle Use Current Time:
    • On — the app uses “now” (date and time fields dim or lock).
    • Off — tap Date and Time fields (and their icons) to set a specific moment to convert.
  6. The Converted Time card shows the target date, time, and zone name/offset.
  7. Tap Save on that card to store the conversion; a dialog may ask for a name—confirm Save or Cancel.
  8. Open history from the top bar to browse past conversions.

Countdown Timer

  1. Tap Utilities → Countdown Timer.
  2. At the top, the quick create card has: a name field, Date (calendar icon), Time (clock icon), and a full-width Create button. Fill them and tap Create to add a timer to the list.
  3. Below, under Active, each timer appears as a card with the name, target date/time, and remaining time (or Paused / Completed).
  4. Use the card’s actions to pause/resume (toggle) or delete (moves to history as deleted, depending on version).
  5. When a timer finishes, you may get a notification (grant notification permission if asked). A celebration overlay can appear—dismiss it to continue.
  6. Tap the History icon in the app bar (when shown) to open Countdown / timer history.
  7. To edit an existing timer, tap the card or edit action your UI provides—some builds navigate to an Update Timer screen with fields and save actions.

Expense Splitter

  1. Tap Utilities → Expense Splitter to open your trips list.
  2. Add a new trip: name it and set optional start/end dates when the form offers them.
  3. Open a trip to reach the workspace. Add people who share costs (first name plus optional last name become the display name).
  4. For each receipt or bill, tap to add an expense: enter amount, choose Paid by from the people list, and add a note or category if shown.
  5. Check the running total and line count against your actual spending.
  6. Tap Calculate to see each person’s equal share, per-person balances, and a simplified settlement list (minimal “A pays B” transfers).
  7. Fix mistakes by editing people or expenses, then run Calculate again.
  8. Use History when the app stores past settlements so you can reopen a closed trip’s summary.

Settings, Premium, feedback & licenses

  1. Tap Settings on the bottom bar.
  2. Use the search bar at the top to filter settings by keyword.
  3. If you are not Premium, a Premium status card may appear at the top—tap it to go to Go Premium.
  4. Scroll through grouped sections (cards). What each control does and where it applies:

Theme (light / dark / system)

Sets how the whole app looks: backgrounds, cards, text, and icons. Light is bright for daytime; Dark reduces glare at night. System follows Android’s display setting, so the app switches when you toggle dark mode in device settings. It does not change math or dates—only appearance.

Haptic feedback & sound effects

Haptic feedback adds short vibrations when you tap buttons, switches, or confirm pickers (where the app supports it). It only works if your phone has a vibration motor and system vibration isn’t disabled. It makes actions feel “confirmed” without changing results.

Sound effects are optional short UI sounds (for example calculator key taps or similar). They are separate from notification sounds for countdowns or alarms—those depend on Android notification channels and your device volume. Turning sounds off here does not silence system alerts.

Decimal places

Controls how many digits appear after the decimal point in numeric results where the app formats fractions or precise values—typically in time math, Calculator, and related summaries. It does not change the underlying calculation; it changes rounding and display (and any text you copy or export that uses the same formatter).

Example: With 2 decimals you might see 1.25 hours; with 4 you might see 1.2500. If you need more precision for mental checks, raise it; if you prefer cleaner numbers, lower it.

Date format

Controls how calendar dates are written across the app: field labels, lists, history, records, and many export/share lines. Formats usually follow a regional pattern (order of day, month, year and separators like /, ., or -).

Where it shows up: date pickers, Smart Time and date tools, workdays, age, time-zone converter date rows, countdown target dates, and anywhere the app prints a full date.

Example: The same day might appear as 02/15/2026 (month first) or 15/02/2026 (day first), depending on your choice—pick the style that matches how you read dates locally to avoid misreading inputs.

Time format

Chooses 12-hour (with AM/PM) or 24-hour for times shown in the UI and in many pickers.

Where it shows up: Smart Time inputs and results, Calculator time-related displays, time-zone converter, countdown timer targets and remaining time where formatted as clock time, aviation or other tools that show local times, and history lines that include a time of day.

Example: 1:30 PM vs 13:30 for the same instant. Use 24-hour if you work across time zones or aviation-style schedules; use 12-hour if that’s what you’re used to day to day.

First day of week

Sets which weekday starts the week row in calendar grids and week-oriented pickers—commonly Sunday (US-style) or Monday (ISO / many business calendars).

Where it affects: any full-month or week-strip calendar when choosing dates; highlighting “this week”; tools that think in weeks (for example skipping weekends in workdays uses Saturday/Sunday, but which column is “first” in the grid follows this setting).

Example: If Monday is first, the left column is Monday; if Sunday is first, Sunday is the first column—same dates, different layout, so your muscle memory for “tap the right column” stays consistent with your paper planner.

Default opening screen

Chooses which tab or starting route opens when you launch the app from the launcher (cold start). It saves repeated navigation if you always begin in one area—e.g. Time Calculators for Smart Time, Date Tools for differences, or Utilities for time zones. It does not change behavior inside a tool; only the first screen you land on.

Privacy & ads consent

Where shown, these entries link to privacy choices or advertising consent flows required in your region (for example personalized vs non-personalized ads). Adjusting them can change how ads are chosen on the free tier; they do not remove the fact that free mode may show ads unless you use Premium. They do not alter calculation features.

Restore purchases (Premium)

Asks Google Play to re-apply entitlements you already bought (subscription or lifetime) on this Google account—use after reinstall, on a new phone, or if Premium status didn’t appear. It does not charge again if a valid purchase exists; it only syncs what Play already records.

Send Feedback

Opens your email app with a pre-filled message to KavNik, or an in-app form, depending on build and device. Use it for bugs, confusing UI, or feature ideas. It does not change settings; it starts a support conversation.

Open Source Licenses

Opens a licenses screen listing third-party libraries used in the app. Tap an entry to read the full copyright and license notice for that component. This is legal/attribution information only—it does not toggle features.

  1. Tap Go Premium (from the card or from a section) to see Monthly and Lifetime plans, prices, and Unlock Premium. Use Restore Purchase at the bottom if you already bought on this Google account.

History, Records & export (Premium)

  • History — opened from the clock/history icon in the top bar on supported screens. Shows a list of past runs; tap an item to view details; use Edit or reload actions where the app offers them.
  • Records — created via Create Record on Smart Time and Calculator; browse from the records destination when available.
  • Export — on Premium, history screens may offer share or export to CSV, PDF, or text. After sharing, the app may show how many exports remain for the month—read that notice on your device.

Messages, validation & navigation tips

  • Toast messages — short pop-ups at the bottom explain validation errors (“enter a valid date”, missing fields, etc.). Read and correct the highlighted field.
  • Upgrade dialogs — appear when a feature needs Premium; you can dismiss or tap through to Go Premium.
  • Interstitial ads (free tier) may appear when moving between some features; Premium removes them.
  • Bottom tabs remember separate back stacks: backing out of a tool returns to that tab’s list, not to another tab.
  • Exact alarms & notifications — for countdowns, grant permissions when Android asks so alerts fire on time.

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