Personal Finance formulas

Enter Monthly income ($) for the 50/30/20 Budget Calculator; retain the units printed in each label. The calculator reports Needs (50%), Wants (30%), and Savings (20%): Classic 50% needs, 30% wants, 20% savings guideline. Use the figure as a planning estimate rather than a guarantee of future costs.

Same fixed-payment formula as a standard installment loan; each row splits interest and principal.

Apply the standard amortizing payment formula.

Raise (1 + r/m) for every compounding period.

Enter Monthly expenses ($) and Months of coverage for the Emergency Fund Calculator; retain the units printed in each label. The calculator reports Target fund ($): Emergency fund target is monthly expenses times months of coverage. Use the figure as a planning estimate rather than a guarantee of future costs.

Compute total paid from fixed payments, then subtract principal.

Multiply principal, rate, and years.

Compound principal and add the future value of deposits.

Payment uses the standard annuity formula with period rate i and N periods.

Use the amortizing payment formula with monthly compounding by default.

Enter Current salary ($) and Raise (%) for the Raise Impact Calculator; enter percentage fields as percentage points and retain the units printed in each label. The calculator reports New salary, Annual increase, and Monthly increase: Pre-tax arithmetic impact of a percentage raise. Use the figure as a planning estimate rather than a guarantee of future costs.

Enter Monthly rent, Monthly mortgage, Tax/insurance monthly, Annual maintenance, Years, Home price, and Loan balance after N years for the Rent vs Buy Calculator; retain the units printed in each label. The calculator reports Total rent paid, Ownership cash cost, and Rent − own cost: Compares total rent cash to ownership cash outflow net of rough equity. This simplified comparison omits appreciation, transaction costs, and tax effects.

Interest equals principal times rate times time.

Total is principal plus interest.

Enter Monthly cost each ($) and Number of subscriptions for the Subscription Cost Calculator; retain the units printed in each label. The calculator reports Annual cost ($): Yearly cost = monthly × 12 × number of subs (or total monthly). Use the figure as a planning estimate rather than a guarantee of future costs.