Step up your numbers.
Decide with the math.
78983 is a free toolkit of money, business and AI calculators — built to show you exactly how growth, interest and costs work, so your next decision is a confident one.
Quick check: what does 300/month become?
At a steady 7% a year, compounding monthly.
Most-used calculators
Live results as you type, charts, schedules, CSV export and a shareable link — on every tool.
Compound Interest Calculator
See how deposits and returns snowball over time.
investingMortgage Calculator
Full monthly cost with taxes, insurance and amortization.
mortgageLoan & EMI Calculator
Monthly installment, total interest and payoff schedule.
loansRetirement Calculator
Project your nest egg and sustainable income.
retirementAI API Cost Estimator
Monthly LLM spend from tokens, traffic and caching.
aiStartup Runway Calculator
Months of runway, burn and break-even with growth.
businessEvery number has a story.
Type any number — a price, a birthday, a house number, a domain — and see its prime factors, binary and hex forms, Roman numeral, divisors and the cultural associations of its digits. For example, 78983 is the product of two primes (19 × 4157) and its digital root is 8.
Explore a number19 × 4157 · digit sum 35 · digital root 8 · binary 10011010010000111
Learn the concepts in minutes
Hand-picked lessons from respected educators, paired with the calculator that puts each idea to work.
Turn your numbers into a plan.
Calculators show the math. People make the decisions. Tell us what you're working on and we'll review it and connect you with a vetted professional or resource that fits — mortgage brokers, fee-only planners, tax pros, debt counselors and AI-automation specialists.
- Independent: we never sell your data to list brokers
- One reply, not a flood of calls
- Works for individuals, freelancers and small businesses
Get your free review
Prefer more detail? Use the full 3-step form.
Monthly contests
Share your best money tip, calculator idea or success story. Winners receive prizes and are featured on the site.
See current challenge →Join the team
We hire freelance writers, developers, video creators and community ambassadors who love making numbers simple.
Open roles →Keep it free
Voluntary support funds new tools, hosting, prizes and talent. Every contributor is credited (if you wish).
Support 78983 →Frequently asked questions
Is 78983 really free?
Yes. All calculators are free with no sign-up. The site is supported by advertising, voluntary support and sponsorships.
Do you store what I type into calculators?
No. Calculations run entirely in your browser. Nothing you enter into a calculator is sent to us.
Is this financial advice?
No. Our tools and guides are educational. For decisions specific to you, use our free review to connect with a qualified professional.
What does the name 78983 mean?
Read it as 7-8-9, then 83: three steps climbing, then a finish. The digits also add up to 35, whose digital root is 8 — a numeral associated with prosperity in Chinese culture. We think it's a fitting name for tools that help numbers grow.
How can my company sponsor or advertise?
See our Advertise & Partner page or use the link in the bar at the top of every page.