Runway Calculator: calculate runway for your business. Formula, benchmarks, and practical tips included.
A = P × (1 + r/n)^(n×t) where P = principal, r = annual rate (decimal), n = compounding periods per year, t = years.
With regular contributions: FV = P × (1 + r/n)^(nt) + PMT × [(1 + r/n)^(nt) − 1] ÷ (r/n) where PMT = payment per period.
Worked example: $5,000 in a Roth IRA at 8% compounded monthly for 30 years. A = $5,000 × (1 + 0.08/12)^(360) = $5,000 × 10.935 = $54,676. Add $500/month: total = $54,676 + $745,180 = $799,856. Total contributed: $5,000 + ($500 × 360) = $185,000. Growth from compounding: $614,856 — more than 3× the total contributed.