Most money and website questions come down to a calculation or a check you can run in under a minute, provided you pick the right tool. TechBullion’s free financial calculators and website tools cover 50 of the questions American households, small-business owners, founders and site owners ask most often, from “how much will my mortgage cost?” to “why is my website slow?”
This guide is organised by the decision in front of you rather than alphabetically. Find your situation, read the one or two lines on what each tool answers, and open the one that fits. The examples use illustrative figures only; rates and prices change, so always enter the numbers you are actually quoted.
Buying a home or a car
The biggest purchases most people make are financed, which means the monthly payment hides the real cost. These tools separate the two.
Should I take a 15-year or 30-year mortgage? The 15 vs 30-year mortgage calculator shows the trade-off between monthly payment and lifetime interest. On a $300,000 loan at an illustrative 6.5%, the 30-year term costs $1,896 a month and about $382,600 in interest; the 15-year term costs $2,613 a month but only about $170,400 in interest.
What will my car really cost each month? The car loan calculator with down payment and trade-in subtracts what you bring to the deal before working out the payment. A $35,000 car with $5,000 down and an $8,000 trade-in leaves $22,000 to finance; over 60 months at an illustrative 7%, that is about $436 a month.
What will it cost after the discount and sales tax? Use the percentage calculator for discounts and sales tax to apply them in the right order. An $80 item at 25% off with 8% sales tax added at checkout costs $64.80.
How much is my dollar worth abroad? Before a trip or an overseas purchase, the US dollar currency converter shows the mid-market value, which lets you judge how much a bank or card provider is adding through its exchange-rate margin.
Borrowing and getting out of debt
Two loans with the same headline rate can cost very different amounts once fees and term length are included. These calculators expose the difference.
Which personal loan is cheaper overall? The personal loan cost calculator compares total repayment across offers. Borrowing $10,000 at an illustrative 11% costs about $1,786 in interest over three years and $3,045 over five, even though the five-year payment looks friendlier.
How is a monthly payment actually calculated? The monthly loan payment (EMI) calculator applies the standard amortisation formula, P × r ÷ (1 − (1 + r)−n). A $20,000 loan at 8% over 60 months works out at $405.53 a month.
What is the true annual cost once fees are included? The APR calculator with origination fees answers it. A $10,000 loan at 10% over three years with a $400 fee deducted up front has an APR of about 12.83%, because you receive only $9,600 but repay as if you borrowed the full amount.
What rate am I really paying? If a lender quotes only a payment, the loan interest rate calculator works backwards. Paying $400 a month for 60 months on $20,000 implies a rate of about 7.42%.
How long will my credit card take to clear? The credit card payoff calculator shows months and interest for a given payment. A $5,000 balance at an illustrative 22% APR takes 52 months and about $2,800 in interest at $150 a month.
How much do extra payments save? The extra debt payment calculator compares plans side by side. Raising that same card payment to $250 cuts the payoff to 26 months and the interest to about $1,286.
Saving and investing
Time and contribution size do most of the work in long-term saving. These tools make that visible, and the last few help you measure what you have already earned.
How does compound interest grow with regular deposits? The compound interest calculator with monthly contributions adds both effects together. A $10,000 start plus $200 a month at an illustrative 7% grows to about $144,600 in 20 years.
How much must I invest each month to hit a target? The monthly investment goal calculator solves for the contribution. Reaching $100,000 in 15 years at an assumed 7% return takes about $315 a month.
What could a fixed monthly amount become? The investment growth calculator projects it. Investing $500 a month for 20 years at an assumed 7% grows to about $260,500 from $120,000 of contributions.
How much interest will a high-yield savings account earn? The high-yield savings calculator shows it, with compounding. As a rough guide, $15,000 at an illustrative 4% APY earns about $600 in a year in an FDIC-insured account.
What will my savings be worth after inflation? The inflation calculator for savings converts future dollars into today’s buying power. At 3% a year, $50,000 in 20 years buys what about $27,700 buys now.
What was my real return on a stock? The total stock return calculator includes dividends and fees, not just price. Buying for $5,000, selling for $6,200, collecting $150 in dividends and paying $20 in fees is a 26.6% total return.
How much do I need invested to earn a set dividend income? The dividend income calculator answers it. Earning $1,000 a month ($12,000 a year) at an illustrative 4% yield requires about $300,000 invested.
Should I reinvest dividends or take the cash? The dividend reinvestment (DRIP) calculator compares both paths. With $50,000, a 3% yield and 5% annual price growth over 25 years, reinvesting ends near $354,500, against about $169,300 in shares plus $71,600 in cash taken out.
What is my average cost when buying monthly? The dollar-cost averaging calculator works it out. Investing $300 at share prices of $50, $40 and $60 gives an average cost of $48.65, below the simple average price of $50, because the fixed sum buys more shares when prices are low.
Did my crypto trade make money after fees? The crypto profit and loss calculator deducts fees on both sides. Buying 0.5 BTC at $40,000 and selling at $50,000 with 0.5% fees each way yields $4,775, not $5,000. US investors should also keep records for IRS capital gains reporting.
Running a small business
Pricing, margins and break-even are the numbers that decide whether a small business survives. Each tool below answers one operating question.
Will this equipment pay for itself? The ROI calculator for business equipment compares gain with cost. A $25,000 machine that saves $8,000 a year over five years returns 60%.
How much of each sale is profit? The net profit margin calculator shows what remains after every expense. $36,000 of net profit on $400,000 of revenue is a 9% margin.
How much do products earn before overheads? The gross profit margin calculator isolates product economics. A product selling for $50 that costs $20 to make has a 60% gross margin.
What price gives me the margin I want? The markup vs margin calculator prevents the classic pricing error. A 50% markup on a $20 cost gives a $30 price, but that is only a 33.3% margin.
How many units must I sell to break even? The break-even point calculator divides fixed costs by contribution per unit. With $6,000 of monthly fixed costs, a $40 price and a $16 variable cost, you need 250 sales a month.
How fast is revenue growing? The revenue growth rate calculator handles month-on-month, quarterly and annual comparisons. Moving from $80,000 to $92,000 in a quarter is 15% growth.
What is my business worth? The small business valuation calculator applies an earnings multiple. $150,000 of owner earnings at an illustrative 2.5× multiple suggests a value around $375,000; real multiples vary by industry, size and risk.
How do I bill a client properly? The free invoice generator for freelancers produces a professional invoice with numbering, payment terms and line items, which also keeps your records tidy at tax time.
Raising money and tracking SaaS metrics
Investors judge start-ups on a handful of ratios. Calculating them yourself, consistently, makes fundraising conversations shorter and more honest.
What will investors own after the round? The pre-money and post-money valuation calculator answers it. Raising $2 million at an $8 million pre-money valuation gives a $10 million post-money valuation and investors 20%.
How much will my stake shrink? The founder equity dilution calculator shows ownership after each round. A founder holding 50% falls to 40% when the company issues 20% to new investors.
How should co-founders split the company? The co-founder equity split calculator weights contributions such as capital, time commitment, role and intellectual property, giving you a reasoned starting point instead of a default 50/50.
How fast are we spending cash? The gross and net burn rate calculator separates total spending from spending after revenue. $120,000 of monthly costs against $45,000 of revenue is a $75,000 net burn.
How long will the money last? The cash runway calculator divides cash by net burn. $900,000 in the bank at a $75,000 net burn gives 12 months of runway.
What is our monthly recurring revenue? The MRR calculator for multiple plans totals subscriptions by tier. 120 customers at $29, 60 at $79 and 10 at $299 produce $11,210 MRR.
What is that as annual recurring revenue? The ARR calculator combines monthly and annual contracts. On its own, $11,210 MRR equals $134,520 ARR; one-off fees should be excluded.
What does each new customer cost to win? The customer acquisition cost calculator includes sales salaries as well as ad spend. $45,000 of sales and marketing spend that wins 50 customers is a $900 CAC.
How much is a customer worth? The customer lifetime value calculator divides margin-adjusted revenue by churn. $100 a month at an 80% gross margin and 2.5% monthly churn gives an LTV of $3,200.
Is acquisition spending sustainable? The LTV to CAC ratio calculator compares the two. A $3,200 LTV against a $900 CAC is about 3.6:1; many investors treat 3:1 as a healthy benchmark.
How many customers are we losing? The customer churn rate calculator measures losses against the starting customer count, excluding new sign-ups. Losing 14 of 400 starting customers in a month is 3.5% churn.
Which metrics should I watch before scaling? The all-in-one SaaS metrics calculator brings MRR, churn, CAC, LTV and payback period into one view, so you can see whether growth is efficient before spending more on it.
Keeping a website fast, secure and findable
For many businesses the website is the shopfront. These checks catch the problems that quietly cost visitors, trust and search rankings.
Why is my website slow? The website speed test reports load timings and points to heavy images, scripts and server delays. Compare results against Google’s Core Web Vitals “good” thresholds: LCP within 2.5 seconds, INP within 200 milliseconds and CLS of 0.1 or less.
Is my SSL certificate valid? The free SSL certificate checker confirms the issuer, expiry date, hostname match and certificate chain, so you can renew before visitors see a browser warning.
Are my redirects set up correctly? The 301 redirect chain checker traces every hop a URL takes. A chain such as http → https → www → new page should be collapsed into a single 301 to the final address.
Is my site missing basic protections? The security headers and mixed content checker looks for HSTS, Content-Security-Policy, X-Content-Type-Options and Referrer-Policy, and flags insecure HTTP resources on HTTPS pages.
Which links on my site are broken? The broken link checker finds 404s and failing external links so you can update or redirect them before they frustrate visitors.
Does this page have on-page SEO errors? The on-page SEO checker reviews titles, meta descriptions, headings, image alt text and canonical tags on a single URL.
How will my page look in Google? The SEO title and meta description preview tool shows whether your snippet will be truncated. Titles of roughly 50–60 characters usually display in full on desktop.
Which campaigns are sending traffic? The UTM link builder adds utm_source, utm_medium and utm_campaign (plus optional utm_term and utm_content) so analytics can attribute each visit correctly.
How do I put my website on printed material? The free QR code generator turns a URL into a scannable code for menus, packaging and flyers. Test it on several phones before printing.
Can AI search engines read my content? The AI search readiness checker reviews robots.txt rules for AI crawlers such as OpenAI’s GPTBot, along with whether your main content is available in the page’s HTML rather than only after JavaScript runs.
Getting a reliable answer from any calculator
A calculator is only as good as its inputs. Use the rate, fee and price you have actually been quoted, not a headline figure. Run at least two scenarios, such as a shorter and longer term or a cautious and optimistic return, because the gap between them is often more useful than either number. Treat projections of investment growth as illustrations, not promises. For website checks, retest after every fix and again after major site changes, since a passing result today says nothing about next quarter’s plugin update.
These tools provide general information rather than financial, tax or legal advice; for large or complex decisions, speak to a qualified professional. Bookmark the TechBullion tools hub and return whenever a new question comes up, from refinancing a loan to renewing a certificate.
