APR ↔ APY Converter

Nominal APR and effective APY answer different mathematical questions in this calculator. The nominal rate is divided across the selected number of equal compounding periods. The effective yield describes the equivalent change over one year when interest remains invested. For example, 12% nominal with monthly compounding becomes 12.682503% effective; reversing the direction recovers 12% nominal for that same frequency. This does not make either rate better or more honest. It makes their conventions comparable. A regulated loan APR can incorporate mandatory charges and a particular payment schedule, so entering that disclosed number as a nominal rate does not reconstruct the loan. Deposit disclosures can also use account-specific terms, calendar-day rules and assumptions outside this simplified model. Use the linked CFPB sources to understand those separate disclosure concepts. In the converter, keep the direction and frequency visible when recording an answer, and compare both quotes under matching assumptions. A percentage-point difference between two rates is distinct from the relative percentage change in those rates. The exact-value display helps avoid confusing a rounded match with mathematical equality.

The rate conversion does not require a balance or investment horizon. Those optional inputs establish a dollar basis when you want to inspect money earned or lost. Upfront fees reduce the amount initially invested, while the entered annual fee is charged at each completed year-end. A percentage annual fee uses the original principal rather than the changing balance. A partial year therefore has no additional prorated annual charge in this model. With no return, aUSD 100 balance and aUSD 10 fee at the first year-end finish at USD 90: the loss remains visible instead of becoming a zero-return result. Annualizing a fee-adjusted balance needs a positive horizon and starting principal; zero-horizon values do not represent an earned annual yield. Tax reduces a positive annualized net yield after fees before compounding, rather than taxing only ending gains; losses receive no tax benefit. It does not model deductions, timing of actual tax payments or account eligibility. Inflation uses the entered constant assumption in the Fisher ratio. Keep gross, net, after-tax and real figures distinct because they describe different adjustments, not interchangeable product disclosures.

A fair dollar comparison holds the starting balance and horizon constant while changing the stated rate convention or disclosed assumptions. Simple nominal interest is a reference line, not a second compounding product. Effective compounded interest assumes retained interest earns the same fixed rate. Net interest reflects the model fees and any specifically labeled adjustment. Without an optional balance, the converter can still show equivalent rates but cannot quantify a personal dollar difference. A zero horizon has no elapsed interest; fees or negative returns can make a later modeled result lower than the starting principal. The scenario and comparison views are illustrations, and benchmark labels do not establish a live market offer, a historical feed or a forecast. Enter actual quoted terms yourself and retain the quote date outside the calculation when evaluating an offer. Additional monthly deposits in the separate projector change the funding assumption, so do not compare that ending balance with a lump sum as though the invested cash were identical. Inspect the table and explanatory text alongside the chart before interpreting a difference. Different liquidity, risk or withdrawal terms remain outside this arithmetic comparison.

The displayed rate is rounded for reading, while exact values and exported data retain the calculated precision available in the model. A visible difference of 0.100 percentage points is 10 basis points; it is not automatically a 0.100% relative change in an investment outcome. Near zero, the conversion uses stable logarithmic and exponential functions, but numerical precision cannot make an unsupported financial assumption accurate. Check that a negative rate remains inside the mathematical domain for the selected frequency, and that a fee has a balance and horizon to which it can apply. Missing or malformed required values should leave dependent results unavailable rather than present a previous calculation as current. Sharing requires an explicit review of the information included in the link; a clean public link need not carry your balance or other inputs. Remembering inputs is a separate local choice and does not validate those values. The editorial dates identify the retained content record, not the date of a market quote. No bank, regulator or third party has certified your personalized result. Use the model as one transparent calculation alongside the actual offer terms and professional advice when appropriate.