Open the network tab
Type your salary in, watch nothing leave. There is no endpoint, no analytics beacon and no third-party script to fire one. That is a fact you can verify in ten seconds, which is more than a privacy policy offers.
The Instruments
Private personal finance calculators Ten Instruments. Nothing Leaves The Page.
The Instruments are ten personal finance calculators that run entirely in your browser. Nothing you type is uploaded, stored or tracked — no account, no cookies, no analytics. Each one opens on a worked example, shows its formula and assumptions, and is checked against an independent second implementation before it ships.
Runs in your browserNothing uploaded or storedLast reviewed
Where To Start
Start From The Question You Have.
I
Plan: Budget Calculators
INSTRUMENT 01
Allocate
Zero-Based Budget Calculator
Enter what actually lands in your account, then hand every unit of it a job — rent, groceries, the trip in March, the card you are digging out of. The plan is finished when To Assign reads zero, not when you feel like stopping.
Open the allocatorTo assignWorked example
$0.00
Take-home$5,000
Envelopes funded10 of 10
INSTRUMENT 02
Split
50/30/20 Budget Calculator
Split take-home pay into needs, wants and savings, then enter what you really spend. It shows which bucket breaks the shape and by how much, and it refuses to rescale ratios that do not total 100.
Check the splitNeeds takeWorked example
57.5%
Target at 50%$2,000
Largest gap+$300 needs
INSTRUMENT 03
Price your hours
True Hourly Wage Calculator
Your stated wage ignores the commute, the unpaid overtime and the costs that exist only because you work. Subtract them, and then price everything you buy in hours instead of currency.
Find the real rateStated → actualWorked example
−26%
Stated$20.77/h
Actually$15.35/h
II
Protect: Subscriptions, Emergency Fund and Sinking Funds
INSTRUMENT 04
Stop the leaks
Subscription Bleed Audit
Add every recurring charge. It normalises the billing cycles, ranks each service by what it costs you per actual use, flags the ones you never open, and prices the whole habit over a decade.
Run the auditAnnual bleedWorked example
$1,164
Paid over ten years$13,975
Ten years, invested$19,601
INSTRUMENT 05
Build a floor
Emergency Fund Calculator
Savings divided by the month you cannot avoid. It is the single most useful number in personal finance and almost nobody knows theirs. Two fields, and you will.
Find your runwayRunwayWorked example
2.0
Target reached33%
Still to save$8,700
INSTRUMENT 06
Fund the future
Savings Goal Calculator
Name each known future cost with its target and its date. It gives one monthly figure that funds them all, with optional interest, and flags any goal that is already covered or already due.
Plan the goalsEvery monthWorked example
$433.33
Goals funded3
Furthest away18 months
III
Borrow: Loan and Debt Calculators
INSTRUMENT 07
Price the loan
Loan Amortization & EMI Calculator
Amount, rate and term in; the monthly payment, the total interest and a year-by-year schedule out, computed in whole cents. Add an extra payment and see the months and interest it saves.
Price the loanMonthly paymentWorked example
$396.02
Total interest$3,761.48
An extra $100 a month saves$893.74
INSTRUMENT 08
Clear the debt
Debt Payoff Calculator
Highest rate first, or smallest balance first? Enter your debts and see both played out side by side — months to clear, total interest, and exactly what the choice costs.
Compare the methodsAvalanche savesWorked example
$92
Time to debt-free2y 6m
Interest avoided$92.42
IV
Grow: Rule of 72 and Net Worth
INSTRUMENT 09
Watch it double
Rule of 72 Calculator
Divide 72 by the rate and you have the doubling time. It sets the shortcut beside the exact answer for money, card debt and inflation, and says which rule is closest at your rate.
Start the clockDoubles inWorked example
9.01
Rule of 72 says9.00 years
At8% a year
INSTRUMENT 10
Measure the position
Net Worth Calculator
Two ledgers, one figure. True net worth, the liquid net worth that is harsher and more honest, the debt-to-asset ratio, and a trajectory that says where the pattern leads in five, ten and twenty years.
Measure the positionTrue net worthWorked example
$42,650
Assets − liabilities$68,300 − $25,650
Debt-to-asset37.6%
Why They Cost Nothing
A Calculator That Phones Home
Is Not A Calculator.
Most finance tools on the web are lead-generation with arithmetic attached. Yours is the data; the maths is the bait. We took the opposite position, and these ten instruments are the proof rather than the promise.
The maths is checked
Every instrument is verified against a second, independently written implementation before it ships. Debt Payoff agrees to the cent across a 30-month simulation. Arithmetic about someone's money is not a place for approximately.
Nothing to maintain
No tax tables, no CPI feed, no jurisdiction logic to rot. Each one answers a question that was true in 1990 and will be true in 2050, which is why they can stay up without becoming a liability.
Questions
The Instruments, Answered Plainly.
Are these calculators really private?
Yes, by architecture rather than by promise. Every calculation runs in your own browser; the pages set no cookies, store none of your figures, load no analytics or advertising script, and make no network request carrying your data. The only thing this site ever stores is your light or dark theme choice. You can confirm all of it in your browser's developer tools.
Do the instruments work offline?
Once a page has loaded, yes. All the arithmetic happens on your device, so you can disconnect and keep calculating. Loading a page for the first time needs a connection, like any website, and nothing is saved when you close the tab — which is exactly the point.
Which calculator should I start with?
If you are not sure where your money goes, start with the 50/30/20 calculator: three numbers show whether your spending has a healthy shape. If you already know, the zero-based budget calculator turns income into a plan. If you pay interest, start with debt payoff. If you want a single figure for where you stand, use net worth.
Why are there no accounts or saved results?
Because anything saved on a server is a copy of your finances that someone else holds. These instruments are built so there is nothing to save and nobody to trust. To keep a result, use Copy summary or print the page. To track your numbers over time, MyneWallet keeps them on your own phone.
How are the calculations verified?
Each instrument is checked against a second implementation written independently from the specification. The two must agree to the cent across a published set of test cases, including edge cases such as zero values and very large numbers. The formulas, rounding rules and test cases for every instrument are listed on the methodology page.
Are the results financial advice?
No. The instruments do arithmetic on the numbers and assumptions you enter, and they explain their formulas so you can judge the results yourself. They are educational tools. For decisions about investments, tax or borrowing that depend on your full circumstances, speak to a qualified adviser.
The Same Argument, Every Day
A Calculator Answers Once.
A Ledger Keeps Answering.
These instruments settle a question in thirty seconds. MyneWallet is what happens when you want the same answer on a Tuesday in March without typing anything in — the same architecture, the same refusal to phone home, running against a ledger that lives on your phone.
Android. Free to use; one-time unlock for the full engine. No subscription, ever.
The instrumentsMyneWallet
Answers a questionBoth
Remembers the answerOnly the app
Tracks it over timeOnly the app
Sees your dataNeither. Ever.