The tools
Pick your calculator
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Mortgage Calculator
Monthly payment, total interest, taxes, insurance, and a full year-by-year amortization schedule.
$320,000 → $1,855/mo
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Refinance Calculator
See your new payment, monthly savings, and break-even point instantly.
Save $312/mo
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House Affordability Calculator
Find your realistic home price range based on income, debts, and down payment.
$85K income → $345K home
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Personal Loan Calculator
Monthly payment, total interest, and full repayment schedule for any personal loan.
$10K → $332/mo
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Auto Loan Calculator
Monthly car payment with down payment, trade-in, and full interest breakdown.
$28K → $561/mo
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Debt Payoff Calculator
Snowball vs avalanche comparison for multiple debts — see your payoff date and total interest.
Debt free in 34 months
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Credit Card Payoff Calculator
See exactly how long it'll take to pay off your card and how much interest you'll pay.
$5K → 4yrs at $150/mo
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Printable Debt Payoff Tracker
Turn a balance into a one-page chart of boxes to print and color in as you pay it down.
$3,500 → 70 boxes of $50
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Printable Emergency Fund Tracker
A one-page savings log with a progress bar marking your first $1,000 and each month of expenses covered.
3 months of $3,000 → $9,000 goal
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Printable Debt Snowball Worksheet
List your debts and the extra you can pay, then print a one-page payoff plan in snowball or avalanche order.
4 debts + $200 extra → $225, $275, $360, $620
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Printable Monthly Budget Worksheet
Plan the month on one page: income, needs, wants and savings, with planned and actual columns and a 50/30/20 check.
$4,000 take-home → 55% / 25% / 20%
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Printable Expense Tracker
Log a month of spending on one page, with a running total, your own categories and a summary at the bottom.
24 lines · 8 categories · budget vs. spent
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Printable 52-Week Savings Challenge
Save a little more each week for a year. Pick classic, reverse or a steady amount and print a one-page chart to check off.
$1 more each week → $1,378 in a year
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Printable 100 Envelope Challenge
Fill 100 numbered envelopes at your own pace. Pick 100, 50 or 25 and print a one-page chart to cross off.
Envelopes 1 to 100 → $5,050 saved
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Compound Interest Calculator
See how money grows over time with compounding — includes yearly breakdown and contributions.
$10K → $76K in 20yrs
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Christmas Countdown
Days and paydays left until Christmas, and how much to set aside from each paycheck.
$800 ÷ 4 paydays = $200
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New Year Countdown
Live countdown to New Year's, plus how much to save each payday to hit next year's goal.
$2,600 goal = $100 a paycheck
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Calorie Calculator
Daily calorie needs based on your age, height, weight, sex, and activity level.
TDEE ≈ 2,340 kcal
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BMI Calculator
Body mass index in metric or imperial, with healthy range context and ideal weight.
BMI 23.6 — Normal
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Body Fat Calculator
U.S. Navy method body fat percentage — just a tape measure, no calipers needed.
17.5% — Fitness
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Age Calculator
Exact age in years, months, and days — for any birth date and any reference date.
36 years, 2 months
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Chronological Age Calculator
A child’s exact age in years;months;days for test scoring, plus corrected age for preemies.
7;6;15
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Dog Age Calculator
Your dog’s age in human years by size — small, medium or large breed.
7-year-old Lab → 50
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Puppy Weight Calculator
How big will your puppy get? Estimated adult weight and a month-by-month growth chart.
15 lb at 4 months → 34 lb
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Net Worth Calculator
Add your assets and liabilities to get a complete picture of your financial health.
Assets − Debt = $284K
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Paycheck Calculator
Estimate your real take-home pay after federal tax, Social Security, and Medicare.
$2,500/biweekly → $1,983 net
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Tax Bracket Calculator
See your marginal and effective 2026 federal tax rate, broken down bracket by bracket.
$75K income → 15.0% effective
In-depth guides
Learn the real numbers
Credit Cards
What is a Good Credit Card Rate?
APR benchmarks by credit score tier and card type — and when your rate actually matters.
Read guide →
Home Buying
Closing Costs Explained
What you'll actually pay beyond the down payment, what's included, and how to lower it.
Read guide →
Credit Scores
Credit Score Minimums by Loan Type
Minimum scores for FHA, conventional, VA, and USDA loans, and how each tier affects your rate.
Read guide →
Our Story
How I Paid Off $3,500 of Christmas Credit Card Debt
A grid of 70 boxes on the fridge and the band gigs that paid it off, $50 at a time.
Read story →
Our Story
We Cut Eating Out to Twice a Month
About $1,700 to $2,200 a year saved, how we did it, and a quick calculator for your own numbers.
Read story →
Our Story
Christmas for 4 Kids on $300, With No Debt
A $300 cap, the 4-gift rule and $25 a week saved ahead. What we bought and how January felt.
Read story →
Why TidyCalcs
Built for real answers
Instant results
No loading screens. Everything updates the moment you type.
Real formulas
Standard lender, WHO, and scientific equations — not rough estimates.
Privacy-first
Everything runs in your browser. Your numbers never leave your device.
Zero friction
No accounts, no sign-ups, no pop-ups. Just open and calculate.
The math behind the answers
Every calculator uses standard published formulas — the same ones used by lenders, doctors, and financial institutions.
Mortgage
Standard fixed-rate amortization formula used by lenders worldwide
Calories
Mifflin-St Jeor equation — the most accurate BMR formula for most adults
Currency
Mid-market rates from global financial data providers, updated daily