FlashCalc: Price & Decisions

Contains adsIn-app purchases
10+
Downloads
Content rating
Everyone
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About this app

FlashCalc: Price & Decisions is a fast, practical discount calculator, percent calculator, rule of three (ratio) calculator (now also inverse proportion), and random picker—built for real-life moments at the store, online, or with friends.

What you can do—instantly

• Check if a discount is truly worth it (new price + savings).

• Apply a markup and see the final price right away.

• Calculate % of a value or what percent a part is of a total.

• Compare different pack sizes with rule of three (direct proportion).

• Solve time/work scenarios with inverse proportion (faster/more → less time).

• Make fair choices with a random decision maker (pick items or shuffle order).


Smart percent calculator

Choose the mode you need and enter values in simple steps (Step 1 → Step 2 → Result):

Discount: original price + % off → new price + “you save”.

Markup: base price + % increase → final price.

Percent of: how much is X% of a value.

What percent: what % does a part represent from the total.


Rule of three (direct & inverse)

No formulas to remember—just type what you know and get the result immediately.


Direct proportion (more quantity → more price / more output):

• Example: 2 kg costs 60 → how much for 3 kg?

• Great for: different package sizes, bulk vs small packs, price-per-amount comparisons.


Inverse proportion (more speed/workers → less time):

• Example: 2 workers finish in 6 hours → how long for 3 workers?

• Example: Drive 100 km at 50 km/h vs 80 km/h → how does time change?

• Great for: “more resources = less time” situations.


Decide & order (random picker)

If you have ADHD (or simply a busy mind), this tool can genuinely make everyday choices easier:

Stops overthinking: add options and let FlashCalc decide in seconds.

Reduces decision fatigue: instant random picks help you move forward instead of getting stuck.

Fair outcomes, no debates: pick one or multiple winners, or shuffle a full order with clear positions (1st, 2nd, 3rd…).

• Great for shopping choices (brands/sizes/flavors), task lists, and turn order in games.

Note: This is a practical decision helper, not a medical or diagnostic tool.



Designed for speed & focus

• Large, readable controls and clear step titles.

• Optional larger controls and reduced animations for calmer use.

• Minimal distractions—built for quick use in real situations.


Personalizable defaults

• Choose the default start tool: Percent / Rule of three / Decision.

• Set your preferred percent mode and decision mode, so the app opens exactly where you need it.


Privacy-first

• No account, no registration.

• Calculations stay on your device.

• Ads may be shown to support development, while keeping the core experience clear and transparent.

FlashCalc is built for the moment you need a clear answer—right now.
Updated on
Jan 27, 2026

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
No data shared with third parties
Learn more about how developers declare sharing
No data collected
Learn more about how developers declare collection

What’s new

- Redesigned Settings
- New Options

App support

About the developer
Viktor Plhák
vikypl@gmail.com
Lázeňská 584 763 14 Zlín Czechia