Frequently Asked Questions

CalcsVault is a free online platform with 65+ calculators for finance, trading, health, math, education and Islamic tools. Every calculator runs instantly in your browser — no login, no installation, no data leaves your device.

Yes. All calculators are 100% free, with no hidden costs, sign-up requirements, or paid tiers.

No account is required. Just open any calculator and start using it instantly.

No. All calculations happen locally inside your browser. Your inputs are never sent to or stored on any server.

Yes. The entire site is fully responsive and optimised for phones, tablets and desktops.

EMI = P × r × (1 + r)^n / ((1 + r)^n − 1), where P is the principal, r is the monthly interest rate, and n is the number of monthly instalments.

Simple interest is calculated only on the original principal. Compound interest is calculated on the principal plus any interest already earned, so it grows much faster over time.

The mortgage calculator uses the standard amortisation formula and is accurate for fixed-rate loans. Real-world payments may vary slightly due to taxes, insurance and lender fees.

Yes. The Tax calculator supports adding or removing GST, VAT or any sales tax for any rate and any currency.

Lot Size = (Account Balance × Risk %) / (Stop Loss in pips × Pip Value). The Forex Lot Size calculator does this automatically for any currency pair.

A pip is the smallest standard price move in a currency pair. Pip value is the monetary value of that move and depends on the pair, lot size and account currency.

Risk-to-reward = (Target − Entry) / (Entry − Stop Loss). A ratio of 1:2 means you stand to gain twice what you risk on each trade.

Yes. The Crypto P&L calculator computes profit or loss from your buy and sell prices, quantity and trading fees.

BMI = weight (kg) / height (m)². For imperial units, BMI = 703 × weight (lb) / height (in)². A BMI between 18.5 and 24.9 is considered normal.

BMR (Basal Metabolic Rate) is the calories your body burns at rest. TDEE (Total Daily Energy Expenditure) is BMR multiplied by an activity factor — your real daily calorie need.

A common guideline is roughly 30–35 ml per kg of body weight, adjusted for activity level and climate. The Water Intake calculator gives a personalised target.

Yes. The Unit Converter covers length, weight, temperature, volume and speed, including common pairs like km↔miles, kg↔lb and °C↔°F.

GPA = Σ(grade points × credits) / Σ(credits). Add each course with its grade and credit hours and the GPA calculator returns your weighted average.

Use the Grade calculator. It maps your percentage to standard letter grades (A, B, C, etc.) and can include weighted assessments.

Prayer times are computed from your geographical coordinates using the public Aladhan API with the ISNA calculation method. Allow location access to see times for your city.

If location access is denied, the calculator falls back to manual city entry. Click 'Use my location' and approve the browser prompt to get times for your actual location.

It calculates the great-circle bearing from your coordinates to the Kaaba in Mecca, then uses your phone's orientation sensor to show a live compass needle pointing toward it.

Zakat is 2.5% of total eligible wealth (cash, gold, silver, business assets, investments) held above the Nisab threshold for one full Islamic lunar year.

Nisab is the minimum amount of wealth a Muslim must have before Zakat is due. It is benchmarked against the value of 87.48 g of gold or 612.36 g of silver.

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No. Your coordinates are only used in-browser to compute prayer times and the Qibla bearing. They are not stored or transmitted to CalcsVault servers.