Free forever · Open 24/7
The Calculator Store for Everyday Decisions
Walk in, find what you need, get your answer. Free online calculators and utility tools for finance, health, home, and daily life — organized like a well-stocked hardware store.
Window Display
Compound Interest Calculator
“The one tool every regular asks for — see how your savings actually grow over the years.”
Try it → DebtDebt Snowball vs Avalanche Calculator
“Two ways to tackle debt — this shows you which one saves more for your situation.”
Try it → RetirementFIRE (Financial Independence, Retire Early) Calculator
“How many years until you never have to work again? Plug in the numbers and find out.”
Try it → LifeCost of Living Comparison Calculator
“Thinking about relocating? See what your paycheck actually buys in another city.”
Try it →From the Workshop
How to Calculate Compound Interest by Hand: A Practitioner’s Step-by-Step Guide
The formula, worked through step by step — no calculator required.
Read the guide →How to Pay Off Debt Fast: Snowball vs Avalanche with a Real-Number Showdown
Two payoff strategies compared on real numbers, not slogans.
Read the guide →How to Calculate Your FIRE Number: A Resilient, Tax- and Healthcare-Aware Worksheet
Work out the number, including taxes and healthcare — which most guides skip.
Read the guide →How to Compare Cost of Living Between Cities: A Personalized Framework Beyond the Calculators
A framework for deciding whether a move actually pays off.
Read the guide →How to Calculate Mortgage Payment by Hand in 4 Simple Steps (A Practical, Jargon-Free Guide)
Four steps, plain language, and the arithmetic behind each one.
Read the guide →How to Calculate NPV Net Present Value: Foolproof From Timeline to Template
From a timeline of cash flows to a number you can defend.
Read the guide →Daily Essentials
Hourly Wage to Salary Calculator
Convert hourly rate to annual, monthly, or weekly pay
Discount Price Calculator
Quickly figure out the sale price and how much you save
Difference Between Dates Calculator
Count the exact days, weeks, or months between any two dates
Cup to Gram Calculator
Cups to grams, tablespoons to ounces — no more guessing
Discretionary Income Calculator
Money left after essentials — know what you can actually spend
Fat Loss Rate Calculator
Track a realistic and sustainable pace for losing weight
Food Cost Percentage Calculator
Figure out your food cost ratio for any meal or recipe
Age in Days Calculator
How many days have you been alive? Now you'll know
Specialty Tools
Cost of Debt Calculator
Calculate the effective rate a company pays on its debt
Leveraged Buyout (LBO) Return Calculator
Model leveraged buyout returns and IRR scenarios
Freight Cost Calculator
Estimate shipping costs across carriers and modes
Economic Value Added (EVA) Calculator
Measure true economic profit after cost of capital
AOV Calculator
Calculate average order value across your store
EV Fleet Transition Cost Calculator
Model the full cost of switching a fleet to electric
529 College Savings Calculator
Project your 529 plan growth vs. future tuition costs
Ghost Kitchen Startup Cost Estimator
Estimate the capital needed to launch a delivery-only kitchen
Backroom Stock
APR Calculator
FINCalculate the true annual percentage rate on a loan
Asset Turnover Calculator
FINMeasure how efficiently a company uses its assets
Balloon Mortgage Calculator
FINCalculate payments on a balloon mortgage structure
Beta Calculator
FINMeasure a stock's volatility relative to the market
Break-Even Units Calculator
BIZHow many units do you need to sell to cover costs?
Business Cash Flow Calculator
BIZTrack operating, investing, and financing cash flows
Customer Acquisition Cost (CAC) Calculator
MKTCalculate customer acquisition cost across channels
Closing Cost Calculator
FINEstimate home purchase closing costs by state
Coupon Campaign ROI Calculator
MKTMeasure the return on a coupon discount campaign
Debt to Income Ratio Calculator
FINCalculate your DTI ratio for mortgage qualification
Employee Cost Calculator
BIZTrue cost of an employee beyond base salary
Escrow Payment Calculator
FINMonthly escrow including taxes, insurance, and PMI
Factoring Calculator
FINCost of selling accounts receivable to a factor
FHA Loan Calculator
FINMonthly payment and upfront MIP for FHA loans
Franchise Fee Calculator
BIZTotal cost of opening a franchise location
Gross Profit Margin Calculator
FINCalculate gross margin from revenue and COGS
Shopkeeper's Note
Orbit Engine started the way most good stores do — we couldn’t find what we needed, so we built it ourselves. Every calculator here was made because someone we know had a real question and couldn’t find a straight answer online.
We organize things the way a hardware store does: by what you’re trying to do, not by abstract categories. Need to figure out a loan? That’s Aisle 1. Evaluating an investment? That’s Aisle 2. Just need a quick unit conversion? That’s up front by the register.
No accounts, no paywalls, no email gates. Walk in, get your answer, get on with your day. We’ll be here when you need us again.
Tools in Stock
470+
Hours
Open 24/7
Price
Always Free