Money
Tip Calculator
Calculate a tip, total bill, and per-person share while seeing the math behind the result.
Enter the bill, tip rate, tax, and group size to see what each person owes and how the total is built.
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Practical answers, without the busywork.
Simple calculators and explainers built to give you a clear starting point, with your inputs staying right in your browser.
Featured utility
Website Tester
Check whether a website responds from your browser and see what the browser can learn about the request. It runs in your browser and explains when a site hides details from browser-based checks.
Money
Compare prices, estimate payments, and understand everyday financial tradeoffs.
Money
Discount Calculator
Find the sale price and total savings, including optional stacked discounts and sales tax.
Useful for checking a sale price before checkout and understanding whether multiple discounts are applied one after another.
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Unit Price Comparison
Compare package prices by ounce, fluid ounce, metric quantity, or individual item.
Normalize different package sizes and units so you can compare the actual cost of what you are buying.
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Debt Payoff Calculator
Estimate a payoff date, total interest, and how much time an extra monthly payment could save.
Compare your current payment with an accelerated plan and see how additional money changes the payoff timeline.
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Savings Goal Calculator
Calculate a monthly savings target or estimate when regular contributions could reach a goal.
Work backward from a target amount and date, with optional interest included when your account earns a return.
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Simple and Compound Interest Calculator
Compare simple and compound interest, effective annual yield, and year-by-year balances.
See how principal, rate, time, and compounding frequency change the balance instead of relying on a single headline number.
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Sales Tax Calculator
Add sales tax, remove tax from a total, or find the effective rate with each formula explained.
Use it when a posted price excludes tax, when you need to separate tax from a receipt total, or when checking a quoted rate.
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Percentage Calculator
Solve common percentage questions, percentage change, and increases or decreases with the formulas shown.
Handle everyday comparisons such as discounts, markups, growth, reductions, and the percentage represented by one value of another.
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Loan Payment Calculator
Estimate fixed monthly principal and interest, total interest, and an amortization schedule.
Explore how loan amount, rate, term, and optional extra costs affect the payment and the total paid over time.
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Fuel Cost Calculator
Estimate fuel needed, trip cost, cost per mile, and each traveler’s share using your own route and vehicle values.
Adjust distance, fuel economy, fuel price, and passengers to create a transparent trip estimate for driving or moving.
Open calculatorMoving
Plan moving costs, compare quotes, and estimate packing supplies before moving day.
Moving
Moving Cost Estimator
Build an itemized moving budget with transportation, travel, setup costs, and a contingency cushion.
Combine known quotes with your own estimates for fuel, lodging, packing, storage, cleaning, and the costs that appear late in a move.
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Moving Quote Comparison
Compare up to three moving quotes side by side, including fees, services, coverage, and contingency-adjusted totals.
Put competing estimates into the same format so missing services, extra fees, and different coverage levels are easier to spot.
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Packing Supply Estimator
Estimate boxes and packing supplies by room, then add your own prices for a private packing-supply budget.
Choose rooms and packing intensity to create a starting shopping list without sending your inventory or prices to a server.
Open estimatorDates
Measure time between dates and answer calendar-based planning questions.
Dates
Age Calculator
Calculate age in calendar years, months, and days for today or another date.
Use a custom comparison date for planning, forms, milestones, or understanding how calendar-based age is counted.
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Date Difference Calculator
Measure the calendar time and weekdays between two dates with clear counting rules.
Compare elapsed days, weeks, months, and business-day counts while keeping the start and end date rules visible.
Open calculatorHome
Estimate materials, household costs, and recipe quantities with visible assumptions.
Home
Paint Coverage Calculator
Estimate paint for a room or wall with coats, openings, coverage, and waste included.
Account for doors, windows, multiple coats, and a practical waste allowance before buying paint.
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Concrete and Gravel Calculator
Estimate volume, concrete bags, or gravel weight for rectangular and circular projects.
Switch between U.S. and metric measurements, include waste, and use editable bag yield or gravel density assumptions.
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Electricity Cost Calculator
Estimate appliance energy use and cost by day, month, and year from watts, usage time, and your rate.
Compare appliances using your own electricity rate without pretending to model every utility’s taxes, fees, or tier rules.
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Recipe Scaling Calculator
Scale ingredient quantities up or down for a different number of servings while preserving the original ratio.
Enter the original serving count and the desired count to resize every ingredient consistently.
Open calculatorHealth
Explore educational estimates for calories, macros, and activity pace.
Health
TDEE Calculator
Estimate resting needs, daily maintenance calories, and practical goal ranges.
Review the formula inputs and activity assumption behind the estimate; it is a planning aid, not medical advice.
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Macro Calculator
Turn a calorie target and macro split into daily protein, carbohydrate, and fat grams.
Start with a calorie target and adjust the percentage split to see the corresponding daily gram targets.
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Pace Calculator
Calculate pace, speed, or finish time for walking, running, cycling, and other distance activities.
Solve for the missing value from any two of distance, time, pace, or speed and keep the units consistent.
Open calculatorElectronics
Work through voltage, current, resistance, batteries, and component values.
Electronics
Ohm's Law Calculator
Calculate voltage, current, resistance, and power while following the formulas.
Enter any two known electrical values to solve for the third and see the resulting power in a low-voltage educational context.
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Battery Runtime Calculator
Estimate battery runtime from voltage, capacity, usable energy, load, and conversion losses.
Adjust usable capacity and efficiency so the estimate reflects the difference between ideal battery energy and real-world load.
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Resistor Color Code Calculator
Decode 4-band, 5-band, and 6-band resistor values, tolerance, and temperature coefficient.
Select each color band to identify resistance, tolerance, and the temperature coefficient where a six-band code provides one.
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Voltage Divider Calculator
Calculate divider output, current, resistor power, and the effect of an optional load.
See how resistor values set the output and why a connected load can pull a divider away from its no-load voltage.
Open calculatorMeasurement
Convert common units and keep length, area, volume, mass, and temperature distinct.
Measurement
SAE and Metric Unit Converter
Convert common length, mass, volume, and temperature measurements between U.S. customary and metric units.
Choose a measurement type and units to see the conversion, the formula used, and a reminder about what the units describe.
Open converterUtilities
Use focused browser tools for practical checks that do not belong to one subject hub.
Utilities
Website Tester
Check whether a website responds from your browser and see what the browser can learn about the request.
Enter a URL to check browser reachability, response timing, and—when allowed—basic status information without sending the address to our server.
Test a website