Just calculators. That’s it
124 free calculators for mortgages, retirement, taxes, health, vehicles, building materials, cooking, business, networking and salary. No sign-up, no paywall, no lead form — and every answer comes with the full working, so you can see exactly how the number was reached.
- Free, no sign-up
- Full working shown
- Published formulas
- 124
- Calculators
- 12
- Categories
- $0
- Cost, forever
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- Sign-ups required
Most calculators hand you a number.These show you the arithmetic.
A figure you cannot check is not much use when the decision is expensive. Every calculator here returns the full breakdown alongside the answer, names the formula it used, and lets you change the assumptions to see what actually moves the result.
The whole calculation, not just the answer
Every result is broken down line by line — which inputs went in, what each component contributes, and how the total was reached. You can see where a number comes from instead of taking it on faith.
Built on published formulas
Standard amortization, current IRS brackets, Mifflin-St Jeor, the US Navy body-fat method, USDA cooking temperatures, RFC-defined addressing rules. Sources are named so you can check them.
Assumptions you can change
Rates, terms, tax years and growth assumptions are all editable. Nothing important is hard-coded behind the scenes, so you can test how sensitive an answer is to the numbers you are least sure about.
Nothing gated, nothing upsold
No sign-up, no newsletter wall, no result withheld until you hand over an email address, and no premium tier. All 124 calculators are complete and free.
Ads keep the site free. They are served in fixed slots and are never given your calculator inputs.
Why CalcToolVault exists
Most of the expensive decisions people make are decided by arithmetic they never see. A lender quotes a monthly payment without showing the interest total. A job offer arrives as a gross salary with no indication of what lands in the bank. A supplier quotes concrete by the yard when the job was measured in feet.
These calculators close that gap. Each one takes the inputs you already know, applies the standard formula, and returns not just the answer but the working — every line item, the sensitivity to the assumptions, and a plain explanation of what the number actually means for the decision in front of you.
Nothing here is behind a login or a lead form. Pick the calculator you need, put your numbers in, and get the answer along with the working — no account, no trial, and no email address required to see the result.
Answers you can act on
Each result ends with what the number actually means for the decision in front of you — whether a payment is affordable, how much a rate change costs, where the break-even sits. Not just a figure to copy down.
Share a link, not a screenshot
The Copy link button encodes your inputs into the URL, so you can send a working calculator to a partner, agent, or contractor and they will see exactly the scenario you set up.
Fast on whatever you are holding
The calculators run in the browser and update as you type, so they stay responsive on a phone in a showroom or on site — no page reloads, no waiting on a server.
Calculators by category
Eight areas, 124 tools. Pick a category to see everything it covers, or jump straight to a calculator below.
Home & Real Estate
Price a mortgage, compare renting against buying, and underwrite a rental before you sign anything.
9 calculatorsRetirement & Benefits
Project your 401(k), model a Roth conversion, and find the number that lets you stop working.
9 calculatorsInvesting & Savings
Compound growth, savings goals, emergency funds, and what inflation quietly does to your money.
8 calculatorsDebt & Credit
Pay off cards and loans faster, compare snowball against avalanche, and see the real cost of borrowing.
7 calculatorsTax Calculators
Estimate federal, state, capital gains, and self-employment tax before the bill shows up.
34 calculatorsHealth & Fitness
Calories, macros, body composition, and training targets built on published formulas.
8 calculatorsAuto & Transportation
Loan payments, lease-versus-buy math, fuel and EV charging costs, depreciation, and towing limits.
7 calculatorsConstruction & Home Improvement
Order the right amount of concrete, gravel, mulch, paint, decking, and flooring the first time.
8 calculatorsCooking & Kitchen
Scale recipes, convert cups to grams, hit the right oven temperature, and pull meat off the heat at a safe internal temp.
9 calculatorsTech & IT
Subnetting, CIDR, IPv6, throughput, MTU, storage sizing, and cloud VM cost estimates.
10 calculatorsSalary & Career
Convert salary to hourly, price overtime and PTO, and work out how long your runway really is.
7 calculatorsBusiness & Freelance
Set a rate that pays you properly, price for real margin, and find the volume where the business starts making money.
8 calculatorsMost-used calculators
The tools people reach for first — the ones behind the biggest numbers in a typical year.
Mortgage Calculator
Estimate your full monthly payment including taxes, insurance, PMI, and HOA — plus total interest and an amortization schedule.
Real EstateCompound Interest Calculator
See what regular contributions plus compound growth turn into over time — and how much of the total is growth rather than deposits.
InvestingTake-Home Pay Calculator
Estimate net pay per paycheck after federal tax, FICA, state tax, retirement contributions, and benefit deductions.
SalaryBMI Calculator
Calculate body mass index, see your category, and find the weight range that would put you in the healthy band.
Health401(k) Calculator
Project your 401(k) balance at retirement including employer match, contribution increases, and fees.
RetirementSubnet Calculator
Calculate network address, broadcast, usable host range, wildcard mask, and host count from any IPv4 address and CIDR prefix.
Tech & ITCar Loan Calculator
Calculate your monthly car payment, total interest, and how trade-in, tax, and fees change the loan.
AutoDebt Payoff Calculator
Compare the avalanche and snowball methods across all your debts, and see exactly what an extra payment buys you.
DebtFederal Income Tax Calculator
Estimate your 2025 federal income tax, effective rate, marginal bracket, and refund or balance due.
TaxFIRE Calculator
Find your financial independence number and the year you can retire early, based on savings rate and spending.
RetirementFreelance Hourly Rate Calculator
Work backwards from the income you want to the hourly rate you have to charge, once unbillable time, expenses, and self-employment tax are taken out.
BusinessRecipe Scaler
Scale any recipe up or down and get the new amounts in measurements you can actually use, not awkward decimals.
CookingMissing a calculator? Found a wrong number?
This site gets better because people point out what is broken. Corrections are fixed before anything new gets built, and the most-requested calculators are the ones that get made.
- A result that does not match what you expected — include your inputs and I can usually find it fast
- A calculator you keep rebuilding in a spreadsheet
- Tax brackets, contribution limits, or wage bases that have gone stale
- An input or assumption you wish you could change
Every calculator, one page
The full index is searchable and grouped by category. Bookmark the ones you use and share a link with your exact inputs already filled in.
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