Methodology
How We Calculate
WalletCalcs uses common consumer finance formulas to create planning estimates. The site is meant to help people get oriented before they talk to a lender, payroll department, tax professional, or financial institution. This page explains how the calculations work, who maintains them, and where their limits are.
Loan and mortgage tools use standard amortization math based on principal, APR, and term. Housing planning tools combine payment estimates with down payment, tax, insurance, debt-to-income, or cash-on-hand assumptions so the result is more realistic than a bare loan formula.
Income tools convert between hourly, weekly, monthly, and annual pay using user-entered work hours and pay periods. Savings and retirement tools estimate growth using recurring contributions, compounding intervals, and time horizon assumptions. Debt tools estimate payoff pace based on recurring payments, interest drag, and extra payment choices.
Where real-world rules vary by employer, lender, state, insurer, tax setup, or account terms, the tools are meant to support rough planning rather than official determinations. Inputs should be adjusted to match your own documents whenever possible.
Who maintains this site
WalletCalcs is built and maintained by Dylan Smith, a single editorial author. Every calculator is checked against worked examples before publication, and every guide is reviewed for clarity, assumptions, and alignment with the calculator it supports. This is deliberate. Personal finance content needs accountability, and WalletCalcs would rather be small, transparent, and correctable than large and anonymous.
Each calculator page includes the author byline and a "last updated" date so you can see when the math was last reviewed. The full author profile is linked from every calculator and from this page.
Accuracy commitment
Every calculator on this site is tested against worked examples before publication. For loan and mortgage tools, that means running the formula against published amortization tables from federal sources. For tax-related tools, that means checking results against IRS publications and state tax tables. For investment tools, that means matching outputs against compound interest tables and well-established retirement planning frameworks like the 4% rule.
That said, the rates, brackets, and limits these tools use can change with new tax laws, Federal Reserve decisions, and provider policies. We update the math when major changes happen, but we cannot guarantee every input default is current to the day. The inputs you enter are always the source of truth — adjust them to reflect your specific situation, current rates from your lender, or current tax brackets for your filing status.
What the calculators do not do
These tools do not replace legal, tax, underwriting, or investment advice. They do not know your full credit profile, benefits elections, lender overlays, or local tax specifics unless you enter assumptions that approximate them.
Specifically, WalletCalcs will never:
- Recommend specific financial products, lenders, insurance providers, or investment vehicles.
- Tell you whether to take out a loan, refinance, switch jobs, or change your investment allocation.
- Sell or share the values you type into a calculator. Inputs are processed in your browser and not transmitted to a server.
- Pretend to know your tax situation, employer benefits, or lender terms beyond what you tell it.
- Replace the advice of a fiduciary financial planner, CPA, attorney, or licensed lender.
WalletCalcs should be used to narrow options, compare scenarios, and prepare better questions, not as the final authority on what you can borrow, owe, earn, or withdraw.
A plain-English example
Here is the kind of check we care about: if a mortgage calculator says a payment is $2,400, the next question is not just whether the formula ran. The next question is whether the page helps you remember the pieces people forget, like property tax, homeowners insurance, HOA dues, closing cash, and the fact that a lender's approval amount may still feel too tight in real life.
That is the standard we use across the site. The calculator should give a clean number. The surrounding copy should help you understand what that number can and cannot tell you. When a page feels too thin, too vague, or too confident, it gets rewritten.
Corrections and feedback
If you find a calculator that returns numbers that don't match what you'd expect, or if a rate or bracket on the site looks outdated, we want to know. Reach out via the contact page with the calculator name, the inputs you used, and what you expected to see. Corrections to math errors are made as quickly as possible, usually within a few days, and the page's "last updated" date is bumped to reflect the change.
The site is not perfect. It is, however, intended to be honest about what it does and doesn't do, and to be corrected when wrong. That commitment is the entire editorial standard.
How to use the site well
- Start with one calculator that fits your immediate question.
- Read the guide content on the calculator page to understand what the result means and what it leaves out.
- Double-check important assumptions against your own loan documents, pay stubs, statements, or account terms.
- Use multiple tools together when the decision crosses categories, such as housing, debt, and savings at the same time.
- Treat results as a starting point for conversations with professionals — not a substitute for them.