⚡ Data Integrity Principles at Gonona BD
- Statutory Reference First: Every computation is built directly from official government gazettes, statutory regulatory orders, national standards (BSTI), or established mathematical algorithms.
- Dual Verification: Tax slabs, utility tariffs, and statutory fees are cross-checked against primary ministry circulars and official portal calculators (e.g. NBR, BERC, BSP, DIP, IRD, Bangladesh Bank, BTRC).
- 100% Client-Side Privacy: None of your personal income, marks, property size, files, photos, or calculations are ever sent to our servers or stored in cookies. Everything executes in your local browser.
- Zero Guesswork: We never estimate arbitrary fees. If a rule has regional or discretionary variables, our calculators ask for your specific input or state the official baseline plainly.
Complete Directory of Tools & Authority Sources
The table below provides the primary legal authority, statutory gazette, regulatory agency, or international computational standard behind each of our 32 tools.
| Tool Name | Primary Authority / Agency | Statutory Basis, Formula & Standard References |
|---|---|---|
| Salary & Income Tax | National Board of Revenue (NBR) | Income Tax Act 2023, Annual Finance Act schedules, Section 153 motor vehicle rules, and Sixth Schedule investment tax rebate calculation. |
| Electricity Bill | Bangladesh Energy Regulatory Commission (BERC) | Retail Electricity Tariff Orders for DESCO, DPDC, NESCO, WZPDCL, BREB (Palli Bidyut); includes lifeline rates (0–50 units), slab tiers, demand charges, and statutory 5% VAT. |
| Sanchayapatra Profit | Internal Resources Division (IRD) & Bangladesh Bank | National Savings Directorate (NSD) multi-slab rate schedules for Family Savings (পরিবার সঞ্চয়পত্র), Pensioner, 3-Month, and 5-Year Bangladesh Sanchayapatra with 5%/10% AIT deductions (Sec 102). |
| Gold Price & Unit | BAJUS & BSTI | Daily bullion rate updates from the Bangladesh Jewellers Association (BAJUS), BSTI hallmark standards (22K 916, 21K 875, 18K 750), and statutory conversion: 1 Vori = 11.664g = 16 Ana = 96 Roti = 960 Points. |
| University CGPA (4.00) | University Grants Commission (UGC) | UGC Unified Grading Policy for all public and private universities in Bangladesh: credit-weighted semester SGPA and cumulative CGPA formulas: [∑(Credits × GP) ÷ Total Credits]. |
| E-Passport & NID Fee | DIP & EC NID Wing | Official Ministry of Home Affairs E-Passport fee schedule across 48/64 pages, 5/10 years, and urgency tiers (Regular, Express, Super Express) with mandatory 15% statutory NBR VAT and Election Commission reissue fees. |
| BRTA Vehicle & License | BRTA & BSP Portal | Road Transport Act 2018, Road Transport Rules 2022 gazette tariff, digital smart card DRC, RFID retro-reflective plate, Road Safety Trustee Fund, 15% VAT, and NBR Income Tax Act 2023 (Section 153) Advance Income Tax (AIT). |
| VAT Calculator | National Board of Revenue (NBR) | Value Added Tax and Supplementary Duty Act 2012; forward and reverse calculations for standard 15% and truncated rates (5%, 7.5%, 10%). |
| Land Measurement | Ministry of Land Bangladesh | Statutory cadastral conversion tables: 1 Shotok/Decimal = 435.6 sq ft (40.468 sq m); 1 Katha = 1.65 Shotok (720 sq ft); 20 Katha = 1 Bigha (33 Shotok / 14,400 sq ft); 100 Shotok = 1 Acre. |
| EMI & Loan Calculator | Bangladesh Bank | Standard reducing-balance amortization formula: EMI = [P × r × (1+r)ⁿ] ÷ [(1+r)ⁿ − 1], compliant with commercial bank interest rate guidelines (SMART / market spreads). |
| Age Calculator (Boyosh) | BPSC & Gregorian Calendar Standard | Proleptic Gregorian calendar leap-year algorithms ensuring exact day, month, and year differences matching Bangladesh Public Service Commission (BCS), government recruitment, and school admission deadlines. |
| FDR Calculator | Bangladesh Bank & Scheduled Banks | Compound interest formula: A = P(1 + r/n)ⁿᵗ, reflecting monthly, quarterly, and semi-annual bank compounding with statutory 10% (with TIN) or 15% (without TIN) source tax deductions. |
| DPS Calculator | Bangladesh Bank | Recurring deposit annuity maturity formula: FV = P × [((1+r/12)¹²ᵗ − 1) ÷ (r/12)] × (1+r/12), with source tax estimation on accumulated interest. |
| HSC & SSC GPA | Bangladesh Education Boards | Official Ministry of Education 5.00 GPA grading benchmarks and 4th-subject bonus rule: Bonus = max(0, GP − 2.00). Handles two-paper 200-mark aggregation for HSC and Golden GPA 5 criteria. |
| BMI Calculator | World Health Organization (WHO) | WHO global BMI standards alongside official WHO Asian-population cut-off thresholds (Normal: 18.5–22.9, Overweight: 23.0–27.4, Obese: ≥27.5 kg/m²). |
| Percentage Calculator | Standard Applied Mathematics | Mathematical formulas for percentage of amount, percentage increase/decrease, relative variance, and percentage distribution. |
| Zakat Calculator | Islamic Foundation Bangladesh & Fiqh Consensus | Hanafi Islamic jurisprudence guidelines on Nisab thresholds (Gold: 7.5 Vori / 87.48g; Silver: 52.5 Tola / 612.36g) evaluated with daily live BAJUS quotes and 2.5% annual rate on net zakatable assets after 1 lunar year (Hawl). |
| Prayer Times (নামাজের সময়) | Aladhan API & Islamic Foundation BD | Astronomical solar calculations (Egyptian General Authority of Survey / Muslim World League) adjusted for Bangladesh geographical coordinates and seasonal Hanafi Asr shadows. |
| Hijri ↔ Gregorian Converter | Umm al-Qura Calendar & National Moon Sighting Committee | Astronomical lunar calendar epoch conversion algorithms synchronized with Islamic Foundation Bangladesh seasonal moon sighting declarations. |
| Bijoy ↔ Unicode Converter | Unicode Consortium & Ananda Computers | Complete two-way mapping between legacy SutonnyMJ/Bijoy ANSI character tables and Unicode Standard Bengali code chart (U+0980–U+09FF). |
| Phonetic Bangla Typing | Avro Phonetic Layout Specification | Rule-based phonetic parsing algorithm converting Latin English keystrokes into correct Bengali conjuncts (যুক্তবর্ণ), vowel signs (কার), and hasant markers. |
| English ↔ Bangla Translator | Bangla Academy Lexicography & Public NLP Models | Lexical alignment and statistical neural machine translation trained on standardized English-Bengali bilingual parallel corpora. |
| Amount to Bangla Words | Bangladesh Bank Cheque Writing Guidelines | Indian-subcontinent numerical grouping (এক, দশ, শত, হাজার, লক্ষ/লাখ, কোটি) formatted according to formal legal cheque and banking invoice standards in Bangladesh. |
| Word & Character Counter | Unicode UAX #29 (Text Segmentation) | Accurate Bengali and Latin grapheme cluster parsing, multi-word whitespace boundary detection, and character counting without splitting composite conjuncts. |
| QR Code Generator | ISO/IEC 18004 Standard | Two-dimensional matrix barcode generation with selectable Reed-Solomon error correction levels (L, M, Q, H) for URLs, WiFi credentials, vCards, and plain text. |
| Currency & Remittance | Bangladesh Bank (FEPD) & BAFEDA | Daily benchmark foreign exchange mid-rates, Crawling Peg exchange rate corridor, statutory 2.5% expatriate wage earner remittance cash incentive, interbank spreads, and Wage Earners Development Bond guidelines. |
| Teletalk Photo & Signature Resizer | Teletalk Bangladesh Ltd & BPSC | Statutory digital recruitment specifications (Photograph: exactly 300×300 px, JPG, ≤100 KB; Signature: exactly 300×80 px, JPG, ≤60 KB) with client-side HTML5 Canvas resampling and zero server uploads. |
| Bangla Calendar & Panjika (পঞ্জিকা) | Bangla Academy (বাংলা একাডেমি) | Official 2019 Bangla Calendar Reform standard: first 6 months (Boishakh to Ashwin) consist of 31 days each, and the last 6 months (Kartik to Chaitra) consist of 30 days each (Falgun has 31 days in Gregorian leap years). |
| Public Holidays (সরকারি ছুটি) | Ministry of Public Administration & Cabinet Division | Official annual statutory holiday notifications approved by the Cabinet Division / Advisory Council, categorizing General Holidays (সাধারণ ছুটি), Executive Order Holidays (নির্বাহী আদেশে ছুটি), and Optional Holidays (ঐচ্ছিক ছুটি). |
| CFT & Construction Volume (সিএফটি ক্যালকুলেটর) | Public Works Department (PWD) | PWD Schedule of Rates for sand/stone truck body volume, sawn timber formula (L×W×T÷144), and international Quarter Girth (Doyle) formula for round log timber. |
| Weight & Agricultural Units (ওজন রূপান্তর) | BSTI & Directorate General of Food | Statutory metric procurement standard (1 Mon = 40 kg), traditional standard (1 Paka Mon = 37.324 kg / 40 Ser), and BAJUS precious metal standard (1 Vori = 11.664 g). |
| Internet Speed & Data (ইন্টারনেট স্পিড) | BTRC & IEEE / IEC Standards | BTRC minimum fixed broadband directive (20 Mbps baseline), standard bit-to-byte conversion (1 Byte = 8 bits), 10% TCP/IP network protocol overhead, and IEC binary storage (1 GiB = 1024 MiB). |
Detailed Methodology by Subject Domain
1. Taxation, Energy & Public Tariffs
Statutory calculators like our Salary Tax, VAT, and Electricity Bill calculators are reviewed whenever national gazettes are released:
- National Budget & Finance Acts: Tax slabs and investment tax rebate rules are updated on July 1st each year following parliamentary approval of the annual Finance Bill.
- BERC Tariff Orders: Retail electricity rates for DESCO, DPDC, NESCO, WZPDCL, and BREB are adjusted based on BERC public hearing gazettes, capturing all slab steps, demand charges, and meter rent.
- BRTA & Motor Vehicles: Motorcycle registration, driving license fees, and car Advance Income Tax (AIT under Section 153) are aligned with Road Transport Rules 2022 and NBR circulars.
2. Banking, Savings & Commercial Finance
Financial calculators (Currency & Remittance, Sanchayapatra, Loan EMI, FDR, DPS) adhere to commercial banking standards and Bangladesh Bank directives:
- Compounding Periods: We apply exact monthly or quarterly compounding as utilized by scheduled commercial banks.
- Source Tax (AIT): Calculations factor in mandatory deductions at source (5%, 10%, or 15%) according to investor TIN status and investment tier limits.
- Amortization: Loan EMI computations utilize standard reducing-balance math rather than misleading flat interest approximations.
- Foreign Exchange & Remittance: Benchmark foreign currency mid-rates under Bangladesh Bank's Crawling Peg system, calculating the statutory 2.5% government remittance incentive on formal banking inflows. See our Currency & Remittance Calculator.
3. Physical Commodities & Land Cadastral Surveys
- Gold & Jewelry: Bullion rates follow BAJUS announcements for 22K (Cadmium), 21K, 18K, and Traditional gold. Weight unit conversions reflect the BSTI metric standard (1 Vori = 11.664 Grams).
- Land Survey Standards: We utilize official Ministry of Land conversion ratios across regional and cadastral units (Shotok, Katha, Bigha, Acre, Square Feet, and Square Meters).
4. Academic Grading Systems
- Secondary & Higher Secondary (SSC/HSC): All 9 general education boards, Madrasah, and technical boards grade on a 5.00 GPA scale. Our HSC & SSC GPA Calculator applies the official 4th-subject bonus formula (Bonus = GP − 2.00) and detects Golden GPA 5 criteria.
- Higher Education (UGC CGPA): University calculations follow the University Grants Commission's unified 4.00 grading scale, calculating credit-weighted semester SGPA and cumulative degree CGPA.
5. Islamic Jurisprudence
Calculators for Zakat, Prayer Times, and Hijri Dates are coordinated with recognized consensus guidelines:
- Nisab Thresholds: Evaluated using the classical Hanafi consensus standards of 7.5 Vori of gold or 52.5 Tola of silver, evaluated against daily BAJUS market prices.
- Prayer Schedules: Calculations are adapted to local Bangladesh geographical coordinates and Islamic Foundation Bangladesh seasonal adjustments.
6. Digital Utilities & Bengali Language Processing
- Legacy Font Conversion: The Bijoy ↔ Unicode Converter maps character encodings directly between SutonnyMJ ANSI and the Unicode 15.0 standard Bengali code range.
- Cheque Writing: The Amount to Words tool adheres to Bangladesh Bank financial transaction conventions and Sub-continental numerical naming (হাজার, লাখ, কোটি).
- Job Circular Photo & Signature Specs: Client-side image processing on the Teletalk Photo Resizer strictly matches the 300×300 pixel (<100 KB) and 300×80 pixel (<60 KB) criteria mandated across government job application portals.
7. Official Bengali Solar Calendar & Statutory Holidays
- Bangla Academy Solar Standard: Our Bangla Calendar implements the reformed calendar adopted by the Government of Bangladesh in 2019, accurately synchronizing historical national events (such as 21 February, 26 March, and 16 December) with fixed Bengali dates.
- Cabinet Division Holiday Gazettes: The Public Holidays Guide is synchronized with the Ministry of Public Administration gazettes, clearly segregating General Holidays, Executive Order holidays, and moon-sighting dependent Islamic festivals.
8. Construction, Agricultural Weights & Digital Standards
- PWD Civil Engineering Volumetric Standards: Our CFT Calculator implements the Public Works Department (PWD) schedule specifications for sand, stone aggregate, truck body volume, sawn timber (L×W×T÷144), and round timber logs using the Doyle Quarter Girth method.
- BSTI Agricultural Metric Standard: The Weight Converter applies the official 40 kg metric maund gazetted by BSTI and the Ministry of Food, alongside the traditional 37.324 kg standard (40 Ser × 80 Tolas) and BAJUS bullion conversions.
- BTRC Broadband Minimum Directives: The Internet Speed & Data Converter strictly incorporates the BTRC 20 Mbps fixed broadband definition and realistic 10% TCP/IP network protocol overhead models.
Our 4-Step Verification Protocol
- Primary Gazette Acquisition: We source original PDF gazettes directly from government ministry repositories (nbr.gov.bd, berc.org.bd, brta.gov.bd, dip.gov.bd, minland.gov.bd).
- Formula Dual-Testing: Every algorithm is tested against real-life utility bills, official bank loan statements, and government challans to guarantee zero discrepancies.
- Periodic Gazette Audits: Our engineering team routinely audits rate cards against new regulatory circulars.
- Rapid Bug Resolution: If an authority changes an interest rate or fee schedule, our codebase is updated within 24 hours of notification.
What Gonona BD Does Not Do
- We do not invent placeholder figures: If an exact fee depends on localized district variables, the calculator prompts the user to input the local quote rather than guessing.
- We do not collect or store user data: Every calculation runs 100% locally in your web browser. No financial data, exam results, or identity details are ever transmitted or saved.
- We are not a substitute for statutory authorities: Gonona BD is an independent computational utility. For legal disputes or binding official payments, the statutory gazettes of the respective government ministries prevail.
Reporting an Outdated Figure or Discrepancy
If you notice a recent government circular, gazette revision, or tariff update that has not yet been reflected on Gonona BD, please report it through our Contact & Feedback Page with a link or citation to the official authority notice. We review and deploy corrections promptly.