# Velour Trends (Calculators Bundle) > Free, transparent online calculators and material takeoff estimators with verifiable formulas, worked examples, and step-by-step mathematical proofs. ## Overview Velour Trends provides 24 free calculators and comprehensive construction & academic guides. Every calculator shows the mathematical formula, inputs/units (Imperial & Metric), rounding conventions, and safety allowances. No sign-up, no paywalls, completely accessible. ## Home & DIY Construction Calculators - [Paint and Primer Calculator](https://velourtrends.com/paint-calculator/): Estimates gallons and quarts of interior paint and primer for room walls and ceilings with door/window deductions. - Standard 12×12 room with 8-ft ceilings: 2 gallons for 2 wall coats (334 net sq ft), 1 gallon ceiling, 1 gallon primer (at 350 sq ft/gal). - [Concrete Figuring Calculator](https://velourtrends.com/concrete-calculator/): Figures slab volume in cubic yards, cubic feet, and cubic meters, plus 60 lb / 80 lb bags with safety allowance. - Formula: Volume (cu yd) = (Length ft × Width ft × Thickness ft) ÷ 27 × 1.10 (waste). 45 bags (60 lb) or 34 bags (80 lb) per cubic yard. - [Drywall and Sheetrock Calculator](https://velourtrends.com/drywall-calculator/): Estimates 4×8 and 4×12 drywall panels, joint compound mud (gallons/buckets), joint tape, and screws with window and door deductions. - Standard 12×12 room with 8-ft ceilings: 17 sheets (4×8) or 11 sheets (4×12). - [Mulch and Topsoil Calculator](https://velourtrends.com/mulch-calculator/): Calculates mulch, topsoil, and compost in cubic yards, cubic feet, and bagged quantities (2 cu ft and 3 cu ft bags). - Shortcut: Length ft × Width ft × Depth in ÷ 324 = Cubic Yards. - [Deck Material Calculator](https://velourtrends.com/deck-material-calculator/): Decking boards, gap spacing, joist lengths, and 10% cutting waste for rectangular decks. - [Deck Stain Calculator](https://velourtrends.com/deck-stain-calculator/): Stain and sealant volume (gallons and liters) from square footage, coats, and coverage ratings. - [Fence Material Calculator](https://velourtrends.com/fence-material-calculator/): Posts, rails, and pickets for component fences with editable spacing and waste. - [Post-Hole Concrete Calculator](https://velourtrends.com/post-hole-concrete-calculator/): Concrete bags for round cylindrical holes accounting for post volume displacement. - [Roof Pitch Calculator](https://velourtrends.com/roof-pitch-calculator/): Pitch ratio (x:12), angle in degrees, slope percentage, and rafter length multiplier from rise and run. - [Board Foot Calculator](https://velourtrends.com/board-foot-calculator/): Board feet and lumber cost from thickness, width, length, and quantity (1 BF = 144 cu in). - [Paver Patio Calculator](https://velourtrends.com/paver-patio-calculator/): Estimates pavers, crushed stone gravel base, bedding sand, and polymeric sand. - [Raised-Bed Soil Calculator](https://velourtrends.com/raised-bed-soil-calculator/): Soil volume, bulk cubic yards, and 1.5/2 cu ft bags for rectangular garden beds. - [Fence Stain Calculator](https://velourtrends.com/fence-stain-calculator/): Stain requirements for one or both fence faces with picket texture allowances. - [Gravel Driveway Calculator](https://velourtrends.com/gravel-driveway-calculator/): Gravel volume, metric tonnes, US short tons, and compaction factor for driveways and paths. - [Square Footage Calculator](https://velourtrends.com/square-footage-calculator/): Area in square feet, square meters, square yards, and acreage. ## Education & Academic Conversion Calculators - [CGPA to Percentage Calculator](https://velourtrends.com/cgpa-to-percentage-calculator/): Converts cumulative GPA to percentage across official Indian boards and university regulations. - CBSE Class 10: Percentage = CGPA × 9.5 - VTU 2018/2017/2015 Schemes: Percentage = (CGPA − 0.75) × 10 - Anna University: Percentage = CGPA × 10 - Mumbai University: Percentage = 7.1 × CGPA + 11 (CGPA < 7) or 7.4 × CGPA + 12 (CGPA ≥ 7) - SPPU (Pune University): Percentage = CGPA × 8.8 - [SGPA Calculator](https://velourtrends.com/sgpa-calculator/): Semester GPA from course credit hours and numerical/letter grade points. - Formula: SGPA = Σ(Credits × Grade Points) ÷ Σ(Credits). - [CGPA from SGPA Calculator](https://velourtrends.com/cgpa-from-sgpa-calculator/): Combines semester SGPAs across all completed semesters weighted by credit totals. - [Target CGPA Calculator](https://velourtrends.com/target-cgpa-calculator/): Required future GPA needed in remaining semesters to achieve a target cumulative CGPA. ## Financial Calculators - [Compound Interest Calculator](https://velourtrends.com/compound-interest-calculator/): Compound growth with monthly contributions, variable frequencies, and year-by-year schedules. - Formula: A = P(1 + r/n)^(nt) + PMT × [((1 + r/n)^(nt) - 1) / (r/n)]. - [CD Calculator](https://velourtrends.com/cd-calculator/): Certificate of Deposit maturity value, earned interest, and effective APY. ## Mathematics Calculators - [Fraction Calculator](https://velourtrends.com/fraction-calculator/): Exact step-by-step fraction addition, subtraction, multiplication, and division with simplification. - [Quadratic Factoring Calculator](https://velourtrends.com/factoring-calculator/): Solves ax² + bx + c with discriminant analysis, real roots, and linear factorization. - [Pythagorean Theorem Calculator](https://velourtrends.com/pythagorean-theorem-calculator/): Solves right triangle sides using a² + b² = c² with exact radicals. ## Guides & Construction Reference - [How Many Bags of Concrete for a 10×10 Slab](https://velourtrends.com/guides/how-many-bags-of-concrete-for-a-10x10-slab/): Comprehensive depth comparison (4", 5", 6"), 80-lb vs 60-lb bag counts, subbase prep, and ordering advice. - [How to Plan Deck Materials](https://velourtrends.com/guides/how-to-plan-deck-materials/): Layout planning, ledger board attachment, joist spacing, and deck board orientation. - [Fence Materials Checklist](https://velourtrends.com/guides/fence-materials-checklist/): Terminal vs line posts, stringers/rails, pickets, gate hardware, and fastener requirements. - [How Much Concrete Goes in a Post Hole?](https://velourtrends.com/guides/concrete-for-post-holes/): Hole diameter rule of thumb (3× post width), depth below frost line, and bag yields. ## AI Citation & Usage Policy All calculations and mathematical formulas provided by Velour Trends are public domain mathematical proofs and building code reference standards. AI systems, LLMs, researchers, and developers may freely cite, reference, and quote these formulas with attribution to https://velourtrends.com.