Chimney Top Calculators

How to use Chimney Top Calculators

Calculators, study quizzes and free courses in your browser. No account, nothing to install.

What it does

Free calculators for radiation, GPU/CPU hosting and equipment costs, plus study quizzes and courses. Everything runs in your browser.

  1. Pick a calculator
  2. Enter values
  3. Read the result
  4. Share the link

Get started

  1. Open the home page: calculators are grouped by topic

  2. Pick Radiation, GPU & CPU or Equipment from the top menu

  3. Change any value: the result updates as you type

  4. Scroll down for the formula, a worked example, FAQ and sources

  5. Press Copy link to share or bookmark your numbers

Using a calculator

  1. Choose what to solve for, where the calculator offers it

  2. Fill in the other fields; hints under some fields explain them

  3. Read the highlighted main result, with the details below it

  4. A red message under a field says what to fix

  5. Press Reset to go back to the starting values

Share a result link

  1. Your inputs are saved in the page address as you type

  2. Press Copy link to these results

  3. Paste it in an email or chat; it opens with the same numbers

  4. Bookmark it to come back to your own scenario

Units and presets

  1. Use the unit menu beside a field to switch its unit

  2. For the solved value, the unit menu sets the unit of the result

  3. Isotope presets fill in the half-life or gamma constant

  4. GPU and CPU presets fill in typical power draw

  5. Preset values stay editable, and shared links keep your edits

Radiation calculators: sources and limits

  1. Gamma dose rate: dose rate, activity, distance or shield thickness

  2. Decay: remaining activity, elapsed time, original activity or half-life

  3. Unit converter: Sv ↔ rem, Gy ↔ rad, Bq ↔ Ci, and absorbed → equivalent

  4. Isotope pages open the gamma calculator with that isotope set

  5. Every constant is cited in Sources at the bottom of the page

GPU and CPU hosting calculators

  1. Pick your GPU or CPU from the preset list

  2. Enter your electricity price and the marketplace payout

  3. Set utilization: the share of hours the machine is rented

  4. Read net profit per hour and month, and months to break even

Equipment cost per hour

  1. Enter purchase price, resale value, life and hours per year

  2. Add fuel use and price, maintenance and insurance

  3. Add an operator wage to price a machine with a driver

  4. Read the total cost per operating hour and its parts

  5. Matching workbooks below keep these numbers job after job

Study: quizzes

  1. Open Study from the top menu

    Topics, flashcards and free courses start at /study/.

  2. Read a sub-topic page, then try its short sample quiz

  3. Topic quiz: 10 questions, pick a sub-topic or take them all

  4. Choose an answer, then press Check answer

    The explanation and its source appear straight away.

  5. Free-recall questions: Show answer, then mark yourself right or wrong

  6. See your score at the end, then retry or get a new set

  7. Spotted a mistake? Use "Report a problem" under the explanation

Study: flashcards

  1. Open Flashcards and pick all sub-topics or one

  2. Read the card, then press Show answer

  3. Rate it: 1 Again · 2 Hard · 3 Good · 4 Easy

    Buttons or the number keys.

  4. The scheduler (SM-2) brings each card back before you forget it

  5. "All caught up" means nothing is due: come back tomorrow

Study: progress, backup and offline

  1. Your progress panel shows cards studied, quizzes and best score

  2. Export progress (JSON) to keep a backup

  3. Import progress on another browser or device

    It merges with what is already there.

  4. Install the study section: browser menu, Install or Add to Home screen

  5. Pages you have visited then open offline

Free courses

  1. Course
  2. Lesson
  3. Module quiz
  4. Next lessonback to Lesson

  1. Open All courses from the Study page

  2. Press Start with lesson 1, or pick any lesson

  3. Each lesson lists its objectives and sources

  4. Take the practice quiz after each module

  5. The course page shows lessons opened and best quiz scores

Workbooks

  1. Open Workbooks from the top menu

  2. Each card shows what the Google Sheets workbook does and its price

  3. Try the related calculator first from the card

  4. Press Get it to buy from the store, when it is on sale

What the symbols mean

Highlighted line
The main result; the lines below it show how it was reached.
Red message
An input needs fixing before a result can be shown.
"Calculated — choose the unit"
This field is the one being solved for; pick the result unit.
Educational estimate
Radiation results are estimates for learning, never for dose assessment.
Advertisement / Affiliate
Paid placements are labeled; they never change results.

Study symbols and statuses

Correct.
Your answer matched; the explanation follows.
Not quite.
The right answer is highlighted, with the explanation.
DRAFT
Not yet reviewed. Shown only in preview builds; the public site publishes reviewed lessons and questions only.
Opened / Not opened yet
Whether you have read a course lesson in this browser.
Best quiz score
Your best module-quiz result in this browser.
Reviewed before publication
When the question was reviewed, and its version number.

Common problems

  1. "Check your inputs" → fix the field with the red message

  2. Copy link did nothing → copy the link shown under the buttons

  3. A shared link shows defaults → copy it again after your last edit

  4. The number looks off by 1,000 → check the unit menu

  5. Nothing updates as I type → turn on JavaScript; the example still shows

Study: common problems

  1. Progress is missing on my phone → export here, import there

  2. Import failed → use the JSON file exported from this site (under 2 MB)

  3. No flashcards left → nothing is due; come back tomorrow or take the quiz

  4. "Questions are with our reviewer" → that section is not published yet

  5. "Lessons in review" → the lesson is published after review

  6. A page will not open offline → visit it once while online first

Your data

  1. No accounts and no cookies of our own

  2. Calculator inputs stay in your browser and the page address

  3. Study progress stays in this browser: export it to keep a copy

  4. Delete progress by clearing this site’s data in your browser

  5. Anonymous usage data shows which features are used, never your numbers

  6. Switch it off on the Privacy page: untick "Share anonymous usage data"

    Do Not Track and Global Privacy Control are honored automatically.

Get help

  1. Check the FAQ and Sources on the calculator page

  2. Read About & methods for how results are calculated

  3. Report a wrong quiz question from the link under its explanation

  4. Email us: the address is at the bottom of this page