📚 Education
GPA, study time, and learning tools — 18 free tools available. No signup required.
Grade calculation, study timing, and reference tools for chemistry, physics, electronics, music and language — the things looked up during coursework or a project.
The grade tools answer the two questions students actually ask: what is my average now, and what do I need on the final to reach a target. The second is the more useful one, and it produces an honest answer including when the target is no longer reachable.
The reference tools are built on bundled data with the source stated, so the values are citable rather than approximate.
Where to start
- College & High School GPA Calculator — Credit-weighted GPA, which is what institutions actually compute.
- Final Grade Calculator — Tells you the mark needed on the final, including when the target has become impossible.
- Interactive Periodic Table of Elements — All elements with atomic properties, electron configuration and discovery data.
- Ohms Law & Electrical Power Calculator — Solves for any of voltage, current, resistance or power from two knowns.
- 4-Band Resistor Color Code Decoder — Decodes 4, 5 and 6-band resistors including tolerance and temperature coefficient.
- Pomodoro Timer — Work and break intervals with the cycle tracked, running entirely in the page.
All education (18)
College & High School GPA Calculator
Semester, cumulative and weighted GPA in one place — with AP and honors bumps, pass/fail exclusions, and a note on…
Pomodoro Timer
A 25/5 Pomodoro timer with custom intervals, automatic long breaks and an alarm, driven by the system clock so it…
Stopwatch & Countdown Timer
A stopwatch timer with laps and countdown, driven by the system clock so it stays accurate in a background tab.
Test Grade Percentage Calculator
Calculate test score percentages, letter grades (A+ to F), and GPA equivalents based on questions missed.
Final Grade Calculator
Calculate the exact minimum score you need on your final exam to pass your class or earn your target letter grade…
Roman Numeral Converter
Convert numbers and dates to Roman numerals and back — and unlike most converters, it rejects invalid numerals…
Book & ISBN Search Explorer
ISBN book lookup in the Open Library catalog — title, authors, publisher, date, pages, subjects and cover — with…
Baby Name Meaning & Origin Explorer
Search hundreds of popular boy, girl, and unisex baby names with cultural origins, historical meanings, and…
World Flags & Capital Cities Quiz
A country flag quiz drawn from the 193 UN member states: half flags, half capitals, ten fresh questions a round…
Interactive Periodic Table of Elements
A periodic table explorer: search any element by name, symbol or atomic number for its atomic weight, group…
Kinematic Velocity & Motion Calculator
Solve classical physics kinematic motion equations. Calculates final velocity (v = v₀ + at), displacement distance…
Ohms Law & Electrical Power Calculator
Enter any two of voltage, current, resistance or power and get the other two — plus the resistor wattage rating…
4-Band Resistor Color Code Decoder
A resistor color code calculator that runs both ways: bands to ohms, and the colors for 1k, 10k and 100k — plus…
Morse Code Translator
A Morse code translator both ways using the complete ITU alphabet, with real-timing audio, adjustable speed and…
English Text to Grade 1 Braille Translator
Convert English letters, numbers, and punctuation marks into standard Grade 1 Unicode tactile Braille patterns…
pH Scale & Hydrogen Ion [H+] Concentration Calculator
pH from concentration, molarity or Ka — with the temperature caveat every other calculator omits: pH + pOH = 14 is…
Musical Note Pitch to Audio Frequency (Hz) Finder
Convert musical note pitch and octave numbers to equal temperament frequency in Hertz (Hz), MIDI key number, and…
Comparative Advantage Calculator
A comparative advantage calculator that computes opportunity cost for two producers and two goods, and shows who…
Weighted and unweighted averages are different questions
A GPA that averages grade points without regard to credit hours answers a question no institution asks. A four-credit course contributes twice as much to your standing as a two-credit one, so the correct calculation multiplies each grade point by its credits, sums, and divides by total credits. Averaging the grades directly gives a different and wrong number whenever courses differ in weight. The same logic applies within a single course: a final worth 40% and a quiz worth 5% do not contribute equally to the outcome.
Grade scales are not standardized
The mapping from a percentage to a letter, and from a letter to grade points, varies by country, institution and sometimes department. Whether an A+ is worth 4.0 or 4.3, whether plus and minus grades exist at all, and where the boundary between B and B− sits are all local decisions. Our calculators use the common US 4.0 scale by default and let you change it, but the authoritative scale is whichever one appears in your own institution's handbook — check it before relying on a projection.
What the study timing tools are actually based on
The Pomodoro technique's twenty-five minute interval is a convention from the method's original description rather than a figure established by research, and the useful part is the structure — a defined work period with a defined break and a deliberate end — not the specific number. Spacing study across several sessions consistently outperforms the same total time in one block, an effect well supported in the learning literature. If twenty-five minutes does not fit your work, changing it does not break anything; abandoning the breaks does.
The reference tools are for checking, not memorizing
Resistor color codes, Roman numerals, Morse code, Braille and musical note frequencies all have the same property: the rule is short, the application is error-prone, and a single transposed digit invalidates the result. These pages state the rule as well as applying it, because knowing that the third band on a four-band resistor is a multiplier rather than a digit is what lets you catch a mistake. The periodic table and physics calculators work the same way, showing the equation alongside the answer.
Frequently asked questions
Which GPA scale do you use?
The common US 4.0 scale by default, and you can change the mapping. Scales differ between institutions, so check your own handbook before relying on a projection.
Can the final grade calculator tell me if I can still pass?
Yes, and it says so explicitly when the required mark exceeds 100% — which is information worth having early rather than discovering afterwards.
Is my grade data saved?
No. Everything is calculated in your browser and nothing is stored or transmitted.
Are the periodic table values citable?
The page states the source of its atomic data. For formal work, cite the primary source rather than this page.
Does the Pomodoro timer keep running if I switch tabs?
It continues counting, though browsers throttle background timers so the display may update less often. Bringing the tab back to the foreground corrects it.