Calculators

Free ratio, percent, date, and video calculators

Available Tools

Freelancer 3.3% Tax Reverse Invoice Calculator
Enter the net pay you want after Korea’s 3.3% freelance withholding. Reverse-calculate supply, optional 10% VAT, and the invoice total, then copy a client quote.
Subscription Cancel D-Day Reminder
Track Netflix, YouTube Premium, Adobe, and more. Enter a free-trial end or next billing date and see the cancel-by D-Day before you are charged. Saved locally, no login.
Stock Averaging-Down Exit Simulator
Averaging-down calculator for stocks and crypto: see how much more cash pulls your average near breakeven, and at what rebound you can exit—with a live chart.
Korea Holiday Business-Day Due Date Calculator
Korea business-day due date calculator with public and substitute holidays. Add or subtract N working days, or count business days between dates—for contracts, delivery SLAs, and CS deadlines.
Overseas Shopping True Card Bill Calculator
Korea overseas-shopping true card bill: convert local checkout with TTS markup and the 1.2% overseas card fee, then warn if CIF exceeds the $200 US / $150 other duty-free limit.
SaaS Runway Survival Calculator
SaaS runway calculator: enter cash, MRR, and burn to see months until zero, a survival grade, and a monthly cash chart—no spreadsheet required.
Part-time Net Pay Reverse Calculator
Reverse a Korean part-time contract wage from take-home pay: weekly holiday pay, night/holiday 1.5×, optional 3.3% withholding, and a copy-ready contract summary.
Tax Invoice Supply / VAT / Total Checker
Fill any one of supply, 10% VAT, or total and get the other two. Flag invoice typos when the three numbers and the rounding mode disagree.
Simplified vs General VAT Compare
Compare Korean simplified vs general VAT from annual supply and purchase invoices: industry add-value rates, the ₩48M exemption, and input-tax credit.
Used Car Consumable Interval Checker
Used-car consumable checker: year and odometer in, overdue oil / trans fluid / timing belt and a shop-cost band out — no garage-app signup.
Indie First-Month Ads ROI Reverse Funnel
Facebook ads ROI reverse calculator: spend, price, CTR and CVR in — break-even impressions, clicks, buyers, and a max CPC/CPM cap out.
Event Prize Budget Optimizer
Event prize budget splitter: total budget plus gift-card prices and min/max counts in — a combination that never overspends, maximizes winners, then burns leftover.
Pixels to Inches Print Size
Pixels to inches print size: convert pixel dimensions to inches at any PPI, see which photo-lab and paper sizes stay sharp, reverse inches to required pixels, or drop a photo to fill the fields. Copy a spec or CSV. Nothing is uploaded.

Calculators

Date & Time

Subscription Cancel D-Day Reminder

13 tools · 13 live