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.