Where did my money go?
Get a clear monthly view of income and spending so the drivers stand out: fixed obligations, flexible categories, and what’s left at the end.
Smarter Money. Clearer Decisions.
FinFormulas is a set of finance calculators and plain-English guides for the money questions that show up in real life. Use it to see your cash flow, compare payments, estimate payoff dates, and run long-range projections with inputs you can follow.
For educational purposes only. FinFormulas provides general estimates and explanations, not financial, tax, legal, or investment advice.
Start With the Question You’re Actually Asking
Most confusion comes from mixing questions. A payment isn’t total cost. A monthly budget won’t fix pay timing. Choose the lane that matches your situation, then jump into the tools built for it.
Can I afford this payment?
See payment, interest, and total cost together so a “similar” monthly number doesn’t hide a very different deal.
When will I be debt-free?
View the payoff path month by month and see how extra payments change the finish date, without guessing where the money went.
Am I on track long-term?
Test time, contributions, and growth rates side by side so scenarios stay comparable without shifting assumptions between runs.
Want the full overview? Start with The Ultimate Guide to Financial Calculators.
Popular Tools
- Budget Calculator
- Mortgage Calculator
- Loan Calculator
- Savings Calculator
- Debt Snowball Calculator
- Net Worth Calculator
- Investment Calculator
- Retirement Calculator
Want everything in one place? Browse all calculators.
Real-World Scenarios (What These Tools Clarify)
These examples are simplified to show what the calculators answer and why results change. The numbers are placeholders so the structure is easier to see.
Cash flow that looks fine on paper, then pinches mid-month. Example: You bring home $4,200/month and the totals look reasonable, yet you’re tight before payday. The usual cause is timing plus category drift: due dates bunch up, autopays land early, and flexible spending expands when there’s no cap. A cash flow view separates what’s fixed from what moves so the pressure points show up quickly. Start with the Budget Calculator, then use the Paycheck Calculator to line up pay timing with bill timing.
Two offers with the same monthly payment and different total cost. Imagine two loans that both land around $430/month, so they feel interchangeable. Small differences in rate and term change how much goes to interest early on and they change total interest over the full timeline. An amortization view makes the split visible and keeps comparisons grounded in totals, not just the monthly number. Compare options with the Loan Calculator (or the Mortgage Calculator for home loans).
Paying consistently while progress feels slow at first. You might see this when you make the payment every month and the balance barely moves for a while. That can be normal early in a payoff schedule because interest takes a larger share at the beginning, then shrinks as the balance comes down. A payoff timeline shows when the curve changes and what extra payments do to the finish date. Model scenarios with the Debt Snowball Calculator, and keep inputs consistent when comparing strategies.
For the bigger picture, start with The Ultimate Guide to Financial Calculators.
How to Read a Result Without Over-Trusting It
When a result feels off, the math is often fine. Most surprises come from timing assumptions or how a rate is quoted.
Timing drives outcomes. Beginning versus end-of-period contributions, billing cycles, and compounding intervals can move totals materially.
Rate labels matter. APR, APY, nominal, and effective rates are related, but they are used differently depending on the product.
Change one input at a time. Keep a baseline, adjust a single variable, then compare totals and timelines, not one rounded monthly number.
Assume real-world friction. Fees, taxes, insurance, points, penalties, and account rules are often outside simplified models unless explicitly included.
If you want the terms in plain language, start with Credit Card APR Explained or browse all guides.
Featured Guides
Short reads on the parts people usually miss—rate definitions, amortization behavior, and compounding timing.
The Ultimate Guide to Financial Calculators
A map of what common calculators cover, what they often exclude, and how to compare results using the same inputs.
How to Make a Budget
A realistic framework for turning income and expenses into a system you can actually run month to month.
Compound Interest Explained
How compounding behaves over time, which inputs drive the curve, and why projections can drift from reality.
Credit Card APR Explained
APR in practical terms, how interest accrues, and why minimum payments can stretch timelines.
Inflation Explained
What inflation measures, what it does not, and how it shows up in everyday prices and long-range planning.
How Taxes Affect Your Money
A high-level view of common tax concepts that influence take-home pay, withholding, and planning.
Browse the full library on Guides.
About the FinFormulas Team
FinFormulas is maintained as an independent educational project. Each calculator answers a specific question, and each guide explains how inputs are treated and what the output represents.
Tools are checked for consistency across definitions (APR vs APY), timing, and rate handling. When an output changes, the goal is for the cause to be clear, along with what the calculator does not cover.
Learn more about the project on the About page.
Standards
No logins. No forms. The calculators run in your browser. The aim is clarity: run comparisons, then understand what the output represents and what it leaves out.
Educational, not prescriptive. Content focuses on mechanics and comparison, not what someone should do.
Clear scope. If fees, taxes, insurance, or rules change the outcome, they are not quietly assumed.
Definitions that match the math. When timing or rate format affects results, the page explains it in plain terms.
Learn more on About and Disclaimer.