Loan Payment
Monthly payment, total interest, and total cost for a fixed-rate loan.
Enter loan details to see your payment.
Amortization Schedule
Payment-by-payment breakdown showing how much goes to principal vs. interest each month.
Enter details to generate the schedule.
Mortgage Payment (Full PITI)
Principal + Interest + Taxes + Insurance, plus optional PMI and HOA.
Enter details to see your full monthly cost.
Compound Interest
Watch a starting amount (plus optional regular contributions) grow over time.
Enter values to project growth.
Savings Goal
How much to save each month to hit a target by a certain date.
Enter your goal to find the monthly amount.
Tip & Bill Splitter
For when the receipt comes and someone hands the math to you.
Enter a bill to split it.
Body Mass Index
A rough indicator using weight and height. Not a substitute for medical advice.
Enter your weight and height.
Calorie Needs (BMR & TDEE)
Estimates resting metabolism (BMR) and daily calorie needs (TDEE) using the Mifflin–St Jeor equation.
Enter your details to estimate calorie needs.
Body Fat % (U.S. Navy Method)
Estimates body fat percentage from circumference measurements.
Enter measurements to estimate body fat.
Heart Rate Zones
Five training zones based on your max heart rate (220 − age) and resting heart rate.
Enter age and resting HR to see your zones.
Daily Water Intake
Rough daily target based on body weight and activity. A starting point — listen to your body.
Enter your weight to see a target.
Countdown to a Date
A live countdown to any moment that matters — a birthday, a trip, a deadline, a wedding.
Pick a date to begin.
Pregnancy Due Date
Estimates due date based on the first day of your last period (Naegele's rule, ~280 days).
Enter your LMP to see your estimated due date.
Exact Age
Years, months, and days between a birth date and today (or any date).
Enter a birth date to see age breakdown.
Days Between Dates
How many days, weeks, and years separate two dates — including business-days only.
Pick two dates to see the gap.
Time Card
Hours worked between a start and end time, minus a break.
Enter your shift to see hours and pay.
Unit Converter
Length, weight, temperature, volume, area, and speed — all in one place.
Enter a value to convert.
Percentage Calculator
Three common percentage questions, all on one page.
Pick a mode and enter two numbers.
Ratio Scaler
Scale a recipe or ratio: A:B = C:?
Enter A, B, and C to find the scaled value.
Fuel Cost / MPG
Estimate the cost of a trip, or your vehicle's fuel economy.
Enter distance, MPG, and fuel price.
Auto Loan
Monthly car payment with down payment, trade-in, and sales tax.
Enter loan details to see your payment.
Debt Payoff
How long it'll take to pay off a balance, and how much interest you'll pay along the way.
Enter your debt details to see the timeline.
Retirement Number (4% Rule)
How big a nest egg you need, and what to save monthly to reach it.
Enter your details to see your retirement plan.
Take-Home Pay (US)
Estimate of net pay after federal tax + FICA. State tax varies; enter as flat % if applicable.
Enter your salary to see take-home pay.
Sales Tax & Discount
Final price after a discount and tax — and how much you saved.
Enter a price to see the final.
Macro Splitter
Daily protein, carbs, and fat in grams from a calorie target.
Enter calories and goal to see your macros.
Running Pace
Calculate pace and speed from a distance and time.
Enter distance and time to see your pace.
Square Footage
Area of a rectangular room or space, with metric conversions and perimeter.
Enter dimensions to see the area.
Paint Coverage
Gallons of paint needed to cover a room's walls (in feet).
Enter dimensions to see paint needed.
Tile / Flooring
Number of tiles needed to cover a floor or wall, with waste allowance.
Enter dimensions to see tiles needed.
Concrete Volume
Cubic yards of concrete for a slab, plus how many bags to buy.
Enter dimensions to see concrete volume.
Lease vs. Buy
Compare the total out-of-pocket cost of leasing versus financing the same vehicle.
Enter both options to compare.
Investment ROI
Return on investment as a total %, plus annualized return (CAGR) over time.
Enter the figures to see your return.
NPV / IRR
Net Present Value and Internal Rate of Return for a stream of cash flows.
Enter cash flows to see NPV and IRR.
Workout Calorie Burn
Estimated calories burned for various activities, based on MET values.
Pick an activity to estimate calories burned.
Ovulation Tracker
Estimates fertile window and next period based on cycle history. For family planning awareness only — not contraception.
Enter your cycle info to see estimates.
Sleep Cycle Calculator
Best wake or bedtime times based on 90-minute sleep cycles. Waking between cycles feels easier.
Enter a time to see ideal sleep windows.
Mulch / Gravel / Topsoil
Cubic yards needed to cover a bed at a given depth, plus number of bags.
Enter dimensions to see how much you need.
Roof Pitch
Convert between rise-over-run, degrees, and percent slope. Plus rafter length.
Enter rise and run to convert pitch.
Stair Calculator
Number of steps, rise, and tread depth from total height and run.
Enter height to see step layout.
Oven Temperature Conversion
Fahrenheit, Celsius, and gas mark — plus the descriptive name (e.g., "moderate").
Enter a value to convert.
Recipe Scaler
Scale ingredient quantities up or down. Enter original and desired servings.
Enter your recipe and serving sizes.
Ohm's Law
Calculate voltage, current, resistance, or power. Fill in any two — leave the others blank.
Enter any two values; the others will be calculated.
Wire Gauge (AWG) Lookup
Recommended copper wire size for a given amperage and run length, with voltage drop estimate.
Enter amperage and distance for a recommendation.
Scientific Calculator
Standard, trig, log, exponents, and parentheses — with M+, M−, MR, MC memory.
Memory: 0 · Mode: DEG
GPA Calculator
Weighted GPA on a 4.0 scale. Leave unused rows blank.
Enter your courses to see your GPA.