Personal-finance literacy reference
Eight money-math concepts, a four-mode calculator, a six-step decision walk, and eight editorial notes. Drag the slider on the right — that's the same APR formula you'll see inside the app.
8 concepts
Each card is one money-math idea — a definition, a formula sigil, and a worked illustration. Inside the app you tap one and read it.
Interest that earns interest. The same rate compounded more often grows a balance faster.
A = P(1 + r/n)^(n·t)
APR is the stated yearly rate; APY folds compounding in. APY is always ≥ APR.
APY = (1 + APR/n)^n − 1
A FICO-style score is a weighted blend of payment history, utilization, length, mix, and new accounts.
Pay 35 / Use 30 / Age 15 / Mix 10 / New 10
The share of pre-tax monthly income that goes to required debt payments. Lower is healthier.
DTI = monthly_debt / gross_income
Three to six months of essential expenses, held in a liquid savings vehicle.
Fund = essentials × months
Real return is the nominal rate adjusted for inflation. A 6% nominal at 4% inflation ≈ 1.92% real.
real = (1+nom)/(1+inf) − 1
Marginal is the rate on the next dollar; effective is the average across all dollars earned.
effective = tax / income
How a flat fee plus a daily rate combine into one comparable effective rate.
(fee/P) × (365/days) × 100
Four tabs
The app keeps every action in one of four places — no marketing pages, no hidden settings buried in flows.
The 8 concept cards above, with category chips, alphabetical / by-depth sort, and a "Try in Math Bench" button on every card.
REFERENCE_BROWSERFour real calculator modes — APR, APY, Payoff months, Utilization — with live formulas and readiness bands. Each input changes a visible result.
ESTIMATORA six-step decision walk: focus area → horizon → tried-the-bench-yet → weak concept → confidence → final move. End on a banded recommendation.
DECISION_TREEEight short editorial articles. Each ends with a one-tap apply chip that opens the matching Math Bench mode or revisits a concept.
GUIDE_ARTICLELocal-only
The app does not ask for an account, a permission, or a payment. Every number you see is computed on your phone from inputs you typed yourself.
Educational reference. Advance Guide teaches money math; it does not provide financial advice, lending, brokerage, or any service connected to an actual financial product. Numbers shown are computed locally from the inputs you provide and do not represent any product offer.
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