Free tools for everyday decisions
Precision calculators for people who run the numbers.
CalcCentral is a growing library of fast, accurate, no-signup utilities. Every tool runs instantly in your browser — no accounts, no paywalls, no fluff. We're rolling out one vertical at a time, starting with the metrics that make or break a real estate deal.
Commercial Real Estate & Investing
Underwrite deals, model cash flow, and pressure-test returns with 15 investor-grade tools.
- BRRRR Calculator: Refinance, Cash Left In & Cash FlowModel a BRRRR rental deal with purchase, rehab, closing costs, loan payoff and cash-out refinance. Calculate cash left invested and post-refinance cash flow.Open calculator →
- Cap Rate CalculatorCalculate the capitalization rate on any commercial property in seconds. Enter income and price to get NOI and cap rate so you can compare deals fast.Open calculator →
- Cash-on-Cash Return CalculatorFree cash-on-cash return calculator for rental property investors. Measure your annual pre-tax cash flow against the actual cash you invested.Open calculator →
- Gross Rent Multiplier (GRM) CalculatorUse our Gross Rent Multiplier calculator to quickly screen rental properties. Divide price by gross annual rent to compare deals before deep analysis.Open calculator →
- Net Operating Income (NOI) CalculatorCalculate Net Operating Income for any income property. Factor in vacancy and operating expenses to find the NOI lenders and investors rely on.Open calculator →
- Debt Service Coverage Ratio (DSCR) CalculatorFree DSCR calculator for real estate investors. Check if a property's net operating income covers its debt so you can qualify for a DSCR loan.Open calculator →
- Fix and Flip Profit CalculatorEstimate your fix and flip profit before you buy. Enter ARV, purchase, rehab, holding, and selling costs to see net profit and ROI instantly.Open calculator →
- Rental Property Cash Flow & Mortgage CalculatorCalculate rental property mortgage payments and monthly cash flow with vacancy, property taxes, insurance, repairs, management and capital reserves. Free US calculator.Open calculator →
- 70% Rule CalculatorApply the 70% rule instantly. Enter the ARV and repair costs to find your maximum allowable offer on a flip or BRRRR property in seconds.Open calculator →
- Internal Rate of Return (IRR) Real Estate CalculatorCalculate the internal rate of return on a real estate investment. Model cash flow, hold period, and sale proceeds to find your IRR and equity multiple.Open calculator →
- Amortization Schedule GeneratorFree mortgage amortization calculator. Enter loan amount, rate, and term to see your monthly payment, total interest, and total cost of the loan.Open calculator →
- 1031 Exchange Timeline & Capital Gains CalculatorPlan your 1031 exchange with our timeline and capital gains calculator. Find your 45-day and 180-day deadlines and estimate the tax you can defer.Open calculator →
- Hard Money Loan CalculatorFree hard money loan calculator. Estimate interest-only payments, origination points, and the total cost of your short-term fix and flip financing.Open calculator →
- Rent vs. Sell CalculatorShould you rent or sell your property? Compare net sale proceeds against long-term rental cash flow and appreciation to make the smarter move.Open calculator →
- Property Depreciation (MACRS) CalculatorFree rental property depreciation calculator using MACRS. Enter price and land value to find your annual and first-year depreciation deduction.Open calculator →
SaaS Metrics & Startup Calculators
Understand acquisition cost, retention, recurring revenue and cash runway.
- Customer Acquisition Cost (CAC) CalculatorCalculate fully loaded customer acquisition cost from sales and marketing spend and new paying customers. Free calculator with a worked example.Open calculator →
- Customer Lifetime Value (LTV) CalculatorEstimate SaaS customer lifetime value using monthly revenue per account, gross margin and monthly customer churn. Free calculator with a worked example.Open calculator →
- LTV to CAC Ratio CalculatorCompare gross-profit customer lifetime value with acquisition cost using the LTV:CAC ratio. Free calculator with a worked example.Open calculator →
- Monthly Recurring Revenue (MRR) Growth CalculatorBuild a monthly recurring revenue bridge from new customers, expansion, contraction and churn. Free calculator with a worked example.Open calculator →
- SaaS Churn Rate CalculatorCalculate monthly customer churn, gross revenue churn and customer retention from the opening customer base. Free calculator with a worked example.Open calculator →
- Burn Rate & Runway CalculatorEstimate startup cash runway from available cash, monthly cash inflows and monthly cash outflows. Free calculator with a worked example.Open calculator →
- SaaS ARPU & ARPA CalculatorCalculate monthly revenue per active paying account and its annualized equivalent. Free calculator with a worked example.Open calculator →
- Viral Coefficient (K-Factor) CalculatorEstimate referral growth from invitations per customer and the share of invitations that convert. Free calculator with a worked example.Open calculator →
- SaaS Quick Ratio CalculatorMeasure recurring revenue gained relative to recurring revenue lost with the SaaS quick ratio. Free calculator with a worked example.Open calculator →
- Magic Number CalculatorCalculate the SaaS magic number from sequential quarterly recurring revenue and prior-quarter sales and marketing spend. Free calculator with a worked example.Open calculator →
- CAC Payback Period CalculatorCalculate how many months of customer gross profit are needed to recover acquisition cost. Free calculator with a worked example.Open calculator →
- Net Revenue Retention (NRR) CalculatorCalculate net and gross revenue retention for the same opening customer cohort, excluding new customers. Free calculator with a worked example.Open calculator →
- Employee Equity Dilution CalculatorEstimate ownership dilution when a company issues additional shares. Free calculator with a worked example.Open calculator →
- Freelance Rate to Salary CalculatorEstimate annual freelance revenue and pre-tax income after business expenses. Free calculator with a worked example.Open calculator →
- Stripe & PayPal Merchant Fee CalculatorEstimate payment processing fees from your supplied percentage and fixed charge per transaction. Free calculator with a worked example.Open calculator →
Fitness, Calories & Body Composition Calculators
Explore calorie, strength and body measurement estimates in US or metric units.
- BMR (Basal Metabolic Rate) CalculatorFree bmr (basal metabolic rate) calculator with worked examples, formula explanations and input checks. US and metric units.Open calculator →
- TDEE (Total Daily Energy Expenditure) CalculatorFree tdee (total daily energy expenditure) calculator with worked examples, formula explanations and input checks. US and metric units.Open calculator →
- Macronutrient (Macro) CalculatorFree macronutrient (macro) calculator with worked examples, formula explanations and input checks. Open calculator →
- Body Fat Percentage Calculator (US Navy Method)Free body fat percentage calculator (us navy method) with worked examples, formula explanations and input checks. US and metric units.Open calculator →
- Lean Body Mass (LBM) CalculatorFree lean body mass (lbm) calculator with worked examples, formula explanations and input checks. US and metric units.Open calculator →
- FFMI (Fat-Free Mass Index) CalculatorFree ffmi (fat-free mass index) calculator with worked examples, formula explanations and input checks. US and metric units.Open calculator →
- One Rep Max (1RM) CalculatorFree one rep max (1rm) calculator with worked examples, formula explanations and input checks. US and metric units.Open calculator →
- Calorie Deficit & Weight Loss Timeline CalculatorFree calorie deficit & weight loss timeline calculator with worked examples, formula explanations and input checks. US and metric units.Open calculator →
- BMI (Body Mass Index) CalculatorFree bmi (body mass index) calculator with worked examples, formula explanations and input checks. US and metric units.Open calculator →
- Waist-to-Hip Ratio CalculatorFree waist-to-hip ratio calculator with worked examples, formula explanations and input checks. US and metric units.Open calculator →
- Protein Intake CalculatorFree protein intake calculator with worked examples, formula explanations and input checks. US and metric units.Open calculator →
- Daily Water Intake CalculatorFree daily water intake calculator with worked examples, formula explanations and input checks. US and metric units.Open calculator →
- Target Heart Rate Zone Calculator (Karvonen)Free target heart rate zone calculator (karvonen) with worked examples, formula explanations and input checks. Open calculator →
- VO2 Max Calculator (Cooper Test)Free vo2 max calculator (cooper test) with worked examples, formula explanations and input checks. US and metric units.Open calculator →
- Ideal Body Weight CalculatorFree ideal body weight calculator with worked examples, formula explanations and input checks. US and metric units.Open calculator →
Grade, GPA & Study Calculators
Plan final exams, check weighted grades, and estimate study workload.
- Final Exam Grade Calculator: What Score Do I Need?Find the final exam score needed for your target course grade using your current average and final weight. Includes achievable and extra-credit examples.Open calculator →
- Weighted Grade Calculator: Course & Assignment WeightsCalculate a weighted course grade from up to six category scores and syllabus weights. See completed-work averages and final-grade examples.Open calculator →
- Cumulative GPA Calculator: Semester & College CreditsUpdate your cumulative college GPA from previous GPA-bearing credits and a new semester GPA on a 4.0 scale. Includes credit-weighted examples.Open calculator →
- Attendance Percentage Calculator: Classes or HoursCalculate attendance percentage from attended and held classes or hours. Check missing attendance and use consistent units.Open calculator →
- Test Grade Calculator: Score Percentage from PointsConvert earned points to a test percentage, including partial credit. Use correct and total questions only when every question has equal value.Open calculator →
- Percent Error Calculator: Measured vs. Accepted ValueCalculate absolute percent error from measured and accepted values, including negative measurements. Includes a lab-report example and zero-reference checks.Open calculator →
- Reading Time Calculator: Words & Reading SpeedEstimate reading time from word count and your reading speed. Plan study sessions with an adjustable words-per-minute assumption.Open calculator →
- Words to Pages Calculator: Estimate Assignment LengthEstimate assignment pages from word count and an adjustable words-per-page density. Includes formatting assumptions and rounded-up page counts.Open calculator →
Home Improvement & Material Calculators
Measure your project, estimate materials, and understand rounding before you buy.
- Square Footage Calculator: Feet, Inches & Flooring AreaCalculate room square footage from feet and inches, convert to square yards, and add a flooring waste allowance. Includes a worked US room example.Open calculator →
- Concrete Slab Calculator: Cubic Yards & Cubic FeetEstimate concrete slab volume in cubic yards and cubic feet using feet-and-inches dimensions, thickness in inches, and an adjustable extra allowance.Open calculator →
- Mulch Calculator: Cubic Yards & BagsCalculate mulch in cubic yards, cubic feet and whole bags from bed dimensions and depth in inches. Adjust bag volume and extra allowance.Open calculator →
- Paint Calculator: Room Coverage & US GallonsEstimate paint gallons for room walls and optional ceilings with doors and windows deducted, multiple coats, product coverage and extra allowance.Open calculator →
- Tile Calculator: Floor Area, Tiles & BoxesEstimate floor or wall tile quantities and whole boxes using room dimensions in feet, tile sizes in inches, and adjustable cutting waste.Open calculator →
- Drywall Calculator: Sheets & Straight-Wall StudsEstimate drywall sheets and straight-wall studs using US dimensions, one or two covered faces, opening deductions, stud spacing and waste.Open calculator →
- Board Foot Calculator: Lumber VolumeCalculate lumber board feet from thickness and width in inches, length in feet and whole-piece count. Includes worked examples and nominal-size guidance.Open calculator →
E-Commerce & Retail
Practical calculations with formulas and worked examples.
- Profit Margin & Markup CalculatorFree profit margin & markup calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- Break-Even Point CalculatorFree break-even point calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- Inventory Turnover CalculatorFree inventory turnover calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- Cost of Goods Sold CalculatorFree cost of goods sold calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- Average Order Value CalculatorFree average order value calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- Conversion Rate CalculatorFree conversion rate calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- Cart Abandonment Rate CalculatorFree cart abandonment rate calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- Return on Ad Spend CalculatorFree return on ad spend calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- GMROI CalculatorFree gmroi calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- Stacked Discount CalculatorFree stacked discount calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- Shipping Dimensional Weight CalculatorFree shipping dimensional weight calculator with instant results, a worked example and formula. No signup.Open calculator →
- Safety Stock & Reorder Point CalculatorFree safety stock & reorder point calculator with instant results, a worked example and formula. No signup.Open calculator →
Baking & Cooking
Practical calculations with formulas and worked examples.
- Recipe Scaling CalculatorFree recipe scaling calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- Baker’s Percentage CalculatorFree baker’s percentage calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- Sourdough Hydration CalculatorFree sourdough hydration calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- Coffee-to-Water Ratio CalculatorFree coffee-to-water ratio calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- Food Yield CalculatorFree food yield calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- Calorie Density CalculatorFree calorie density calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
Freelance Work & Logistics
Practical calculations with formulas and worked examples.
- Billable Hours CalculatorFree billable hours calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- Project Cost Variance CalculatorFree project cost variance calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- Client Retainer Burn CalculatorFree client retainer burn calculator with an instant result, formula, worked example and input validation. No signup.Open calculator →
- Fuel Surcharge CalculatorFree fuel surcharge calculator with instant results, a worked example and formula. No signup.Open calculator →
Automotive Costs
Estimate costs and compare your numbers.
- Gas Mileage & Fuel Cost CalculatorFree gas mileage & fuel cost calculator with instant results, a worked example and formula. No signup.Open calculator →
- Car Depreciation CalculatorFree car depreciation calculator with instant results, a worked example and formula. No signup.Open calculator →
- EV vs. Gas Energy Cost CalculatorFree ev vs. gas energy cost calculator with instant results, a worked example and formula. No signup.Open calculator →
- Out-the-Door Car Price CalculatorFree out-the-door car price calculator with instant results, a worked example and formula. No signup.Open calculator →
- Car Ownership Cost CalculatorFree car ownership cost calculator with instant results, a worked example and formula. No signup.Open calculator →
Personal Finance & Budgeting
Estimate costs and compare your numbers.
- Debt-to-Income Ratio CalculatorFree debt-to-income ratio calculator with instant results, a worked example and formula. No signup.Open calculator →
- Emergency Fund CalculatorFree emergency fund calculator with instant results, a worked example and formula. No signup.Open calculator →
- Net Worth CalculatorFree net worth calculator with instant results, a worked example and formula. No signup.Open calculator →
- 50/30/20 Budget CalculatorFree 50/30/20 budget calculator with instant results, a worked example and formula. No signup.Open calculator →