Compound Mint Money Calculator

Use first when a user asks a money math question in plain words, such as "how much will $500 a month grow in 20 years?", "when can I retire if I spend $40,000 a year?", "how long to pay off $5,000 on my credit card at 24% paying $200 a month?", "how much do I need to save each month to have $50,000 in 5 years?", "how long to double my money at 8%?" or "am I getting my full 401(k) match?". Reads the amounts, rates, ages and years from the question, picks the matching Compound Mint calculator (compound interest, Rule of 72, FIRE number, Coast FIRE, 401(k) match, debt payoff, savings goal), runs it and returns the answer with what it understood, the explanation, the assumptions, source_page to cite and related_reading. When a needed number is missing it returns status need_more_info with the exact question to ask the user.

Use when a user asks how much money will grow, e.g. "how much will $500 a month grow in 20 years?", "what will $10,000 be worth in 10 years at 7%?" or "how much interest will I earn?". Future value of a starting amount plus optional monthly contributions at a yearly rate, with total contributed and total interest. Compounding is monthly by default (annually, quarterly, semiannually or daily on request). Returns a plain-English explanation, the assumptions and the matching Compound Mint calculator page. Example: $10,000 at 7% for 10 years compounded annually = $19,671.51.

Use when a user asks how long it takes to double money ("how long to double my money at 8%?") or what return doubles it in a number of years. How long money takes to double at a yearly rate (send annual_rate), or the rate needed to double in a number of years (send years). Gives the Rule of 72 estimate and the exact figure. Example: at 8% money doubles in about 9 years.

Use when a user asks about Coast FIRE, e.g. "what is my Coast FIRE number at 30?" or "can I stop saving for retirement and let it grow?". FIRE number (yearly spending / withdrawal rate) and Coast FIRE number: what you need invested now so growth alone reaches your FIRE number by retirement age. Add current savings and a monthly contribution to see the gap and the age you reach Coast FIRE. Uses a real (after inflation) return, 7% by default; same math as the Compound Mint Coast FIRE calculator.

Use when a user asks when they can retire or how much they need to retire, e.g. "when can I retire if I invest $1,500 a month?", "what is my FIRE number if I spend $40,000 a year?" or "how many years until I can stop working?". Returns the FIRE number (yearly spending / withdrawal rate, 25 times spending at 4%) and, from current savings and a monthly contribution, the months and years to reach it and the age if current_age is given. Uses a real (after inflation) return, 7% by default; same math as the Compound Mint FIRE number calculator.

Use when a user asks how much to spend on the holidays or on Christmas gifts, e.g. "how much should I budget for Christmas?", "can I afford $50 gifts for 8 people?" or "how much do I need to save each week for the holidays?". Adds gifts (people x budget per person), travel, food and decor; returns the total, its share of monthly take-home pay, weeks of saving needed, cash by the holidays and a spend limit (spend this, not more), plus the per-person gift budget that fits. Same math as the compoundmint.com holiday budget calculator. Educational only, not financial advice.

Use when a user asks how to split a Christmas or holiday gift budget between people, how much to spend on each person, or what it costs to put gifts on a credit card, e.g. "split $800 for gifts between 5 people", "I have $600: Mom 30%, Dad 30%, my sister 40%", "is $150 for mom and $100 for dad within my $300 budget?" or "how much interest if I put $800 of gifts on a 22% card for 6 months?". Budget comes from total_budget, or monthly_income x percent_of_income, or already_saved + monthly_savings x months_until_shopping. Splits it evenly, by percent or by a set amount per person; returns each person's amount, the total, what is left or over budget and, with card_apr, the monthly payment and interest. Same math as the compoundmint.com Christmas gift budget calculator. For a whole holiday plan with travel, food and decor use calculate_holiday_budget. Educational only, not financial advice.

Use when a user asks about a 401(k) employer match, e.g. "am I getting my full 401(k) match?", "how much is my employer match worth?" or "what percent should I put in to get the full match?". Your yearly 401(k) contribution, the employer match, the percent needed for the full match and any match left unclaimed, using 2026 IRS limits ($24,500 employee, catch-up at 50 and over and at 60 to 63, $72,000 overall, $360,000 pay cap). Supports a two tier formula such as 100% up to 3% then 50% of the next 2%. Optional years and annual_return project the balance.

Use when a user asks how long it takes to pay off a credit card or loan, what payment clears it by a date, or avalanche vs snowball, e.g. "how long to pay off $5,000 at 24% paying $200 a month?" or "what payment pays off my credit card in 2 years?". One debt: months to pay off and total interest at a monthly payment, or the payment needed to be debt free in target_months. Several debts: send debts (each with name, balance, apr, min_payment) and extra_payment to compare the avalanche and snowball methods.

Use when a user asks how much to save each month for a goal, e.g. "how much do I need to save each month to have $50,000 in 5 years?" or "how much a month to reach $1 million in 30 years?". Monthly amount to save to reach a target in a number of years at a yearly rate, counting money already saved. Example: $1,000,000 in 30 years at 8% needs about $671 a month.

Use when a user asks about a mortgage or house payment, e.g. "what is the monthly payment on a $400,000 house with 20% down at 6.5%?", "how much interest will I pay on a $300,000 mortgage?" or "15 vs 30 year mortgage payment". Monthly principal and interest for a fixed rate loan, total interest, first payment split, balance after 5 years and the same loan on a 15 or 30 year term. Optional property tax, home insurance, HOA and PMI give the full monthly payment. Example: $320,000 at 6.5% for 30 years = $2,022.62 a month.

Use when a user asks what inflation does to money, e.g. "what will $100 be worth in 10 years with inflation?", "how much will a $50,000 salary need to be in 20 years?" or "how much purchasing power does cash lose at 3% inflation?". Future cost of something priced today and the purchasing power of today's money in the future (in today's dollars), plus how long prices take to double. Inflation defaults to 3% a year, an assumption, not a forecast. Example: $100 kept as cash for 10 years at 3% buys what $74.41 buys today.

Use when a user asks how much they will have when they retire, e.g. "how much will I have at 65 if I save $500 a month starting at 30?", "will $20,000 plus $300 a month be enough by 60?" or "project my retirement savings". Projects the balance at retirement from current savings and monthly contributions (optionally raised each year), shows it in today's dollars, the total put in, the growth, the balance every 5 years and an estimated yearly income at a withdrawal rate. Example: $500 a month from 30 to 65 at 7% grows to about $900,527.

Lists every calculator tool with its inputs, an example and its REST endpoint.

Takes no parameters.

Searches Compound Mint calculators and personal finance guides. Returns results with id, title and url; read one with fetch.

Returns the text of one Compound Mint page by id (from search) or by URL.