All SpecWhale tools

Generate a real, scannable Code 39 barcode (0-9, A-Z, space, hyphen, period) as a downloadable SVG.

Convert pasted SVG markup into a PNG image locally.

Count lines, words, and characters in a local text file.

Remove duplicate lines while preserving the first occurrence.

Count pages in a local PDF by scanning the file structure in your browser.

Count the total days, weeks, and business days between two dates instantly.

Count weekdays between dates, with optional weekend exclusion.

Add or subtract days, weeks, months, or years from a date.

Calculate age in years, months, and days.

Calculate someone's age on a specific past or future date.

Convert a date and time between IANA time zones.

Compare working-hour overlap across multiple time zones.

See current times in popular cities and time zones.

Create a local countdown to a date and time.

Run a clean browser stopwatch with lap times.

Run a local Pomodoro timer for focused work sessions.

Find the ISO 8601 week number for any date, using Monday as the start of the week.

Calculate invoice due dates from issue date and net terms.

Estimate pay period ranges from a start date and cadence.

Look up public holidays by country and year using the free Nager.Date API.

Calculate what percent one number is of another.

Find percentage increase or decrease from an old value to a new value.

Calculate sale price and savings from a discount percentage.

Compare price per unit for groceries, supplies, and bulk purchases.

Calculate tip amount, total, and split per person.

Calculate profit margin from cost and selling price.

Calculate markup percentage from cost and selling price.

Calculate units needed to break even from fixed cost, price, and variable cost.

Calculate return on investment from cost and gain.

Convert an annual salary to an hourly rate based on your weekly work hours.

Estimate monthly loan payment from principal, APR, and term.

Estimate principal and interest mortgage payment.

Calculate future value with compound interest and monthly contributions.

Find the monthly savings needed to reach a target amount.

Estimate payoff time from balance, APR, and monthly payment.

Calculate body mass index from height and weight.

Estimate basal metabolic rate with the Mifflin-St Jeor formula.

Estimate total daily energy expenditure from BMR and activity multiplier.

Estimate heart rate training zones from age.

Calculate running pace from distance and time.

Estimate wake-up times based on 90-minute sleep cycles.

Estimate gallons of paint needed for walls.

Estimate flooring material with waste allowance.

Estimate tile count from area and tile size.

Estimate concrete volume in cubic yards for slabs from length, width, and depth.

Estimate mulch volume from area and depth.

Estimate electricity cost from watts, time, and price per kWh.

Calculate average from a list of numbers.

Scale a ratio up or down while keeping the same proportion between its parts.

Solve a proportion a/b = c/x for the missing value x.

Calculate circle area, circumference, and diameter from radius.

Calculate standard deviation for three values.

Calculate weighted GPA from three courses.

Search country calling codes for international dialing.

Search common currency codes, symbols, and names.

Search standardized country names and ISO alpha-2 codes locally in your browser.

Get a simple forecast from Open-Meteo's free geocoding and forecast APIs.

Estimate trip budget from days, daily spending, lodging, and travel cost.

Estimate trip fuel cost from distance, MPG, and fuel price.

Convert luggage weight between pounds and kilograms.