About Hatdool
Everyday math—change inputs and compare side by side
Hatdool is a collection of online calculators for investment planning, marketplace pricing, loan repayment, housing costs, and everyday numbers. Pick a category or search, then change the same figures under different assumptions and compare results.
How to use
Find a calculator
On the home screen, choose investing, loans, property, business, everyday math, or search by tool name.
Enter your inputs
Each tool explains its fields and assumptions. Match units, periods, and payment timing to your situation.
Compare results
Change rate, term, or repayment style and compare monthly payment, total cost, and other metrics side by side.
Example
Same rate, different repayment—payments change
The loan calculator converts an annual rate to a monthly rate and compares equal payment, equal principal, and bullet repayment on the same principal, rate, and term. Monthly payment and total interest differ by style—check both numbers before choosing.
Details
Reading results
Check units and periods first. Results are reference estimates from your inputs. Actual institution day-count, fees, tax, and personal circumstances can differ. This is not investment, tax, or legal advice.
Assumptions · periods · units · timing
Compound interest assumes end-of-month contributions; dividend additional investments assume month-start. Deposit and savings tax rates are user-entered. Compare on-screen assumptions to your product terms.
Dividend data basis
For ETF distribution rates, check the as-of date and source in the static data. On fetch failure, older data may show. Past distributions do not guarantee future payouts or principal.
Sign-in and saved settings
Calculators work without signing in. Saving, loading, and deleting input presets requires an account. On supported calculators—including marketplace selling price and dividend—you can pick a saved name to reload or delete. Dividend saves include distribution rate at save time and any tax or health insurance values you entered.
Optional visit analytics
Google Analytics runs only if you allow visit statistics. Page views may include referrer origin on external visits. Calculator inputs, account data, URL queries, and hashes are not sent. You can stop collection later in visit analytics settings at the bottom of the site.
Operator
Displayed operator: Hatdool operator.
Contact and policies
For usage questions, bug reports, feature ideas, or account and privacy inquiries, use the email on the contact page: toolboard.help@gmail.com.