Pocket Desk
App manual

Five tools, documented plainly.

Each app on the desk is small on purpose. This page says what it does, how to drive it, what it quietly assumes, and what happens when the input is empty, negative, huge or not a number. No tool here looks anything up. Every rate is typed by you.

Sats converter

Open on the desk

What it does

Moves a quantity between satoshis, bitcoin and a fiat figure. Satoshis are the base unit: one bitcoin is 100,000,000 of them, and nothing smaller exists on-chain. The converter keeps three boxes in step so you can start from whichever number you actually have.

How to use it

  1. Optionally type a currency label (for example the three letters of your own currency) and the price of 1 BTC you want to assume.
  2. Type in any of the three boxes. The other two update as you type. The box you are typing in is never rewritten under your cursor.
  3. Use the quick values to jump to a round starting point, or Clear to begin again.

Assumptions

  • The rate is whatever you typed. Pocket Desk has no price feed, so a fiat figure is just your amount multiplied by your number.
  • There are no spreads, fees or taxes in the conversion. It is arithmetic, not a quote.
  • Bitcoin amounts are exact to eight decimal places, because one sat is the smallest unit.

Edge cases

  • Fractions of a sat are rounded to the nearest whole sat, and the status line says so.
  • Empty, negative and non-numeric input produces a plain explanation rather than zeros or errors.
  • Amounts above the 21 million BTC supply cap are allowed for arithmetic and flagged. Anything beyond exact precision is refused.
  • Typing a fiat amount before a rate exists asks you for a rate rather than guessing one.
Three linked boxes. Sats divided by 100 million gives BTC. BTC times your rate gives fiat. Fiat divided by your rate gives BTC again. sats BTC fiat รท 100,000,000 rate rate
Sats converter: the idea in one picture.

Tip splitter

Open on the desk

What it does

Splits a bill plus a tip between up to 99 people, either in currency with two decimals or in whole sats. When the total does not divide evenly, the tool tells you exactly who pays one extra unit instead of hiding a rounding error.

How to use it

  1. Pick whether the bill is in currency or in sats.
  2. Type the bill amount, then a tip percentage or one of the presets.
  3. Set the number of people with the plus and minus buttons or by typing. The shares appear below, one row per person for groups of twelve or fewer.

Assumptions

  • The tip is a percentage of the bill before tip, rounded to the smallest unit (a sat, or a hundredth of a currency unit).
  • Shares differ by at most one smallest unit. The first people in the list carry the extra unit and are marked with +1.
  • Everyone gets a share of the tip; the tool does not model uneven consumption.

Edge cases

  • A tip of zero is valid. A tip above 100 percent is allowed and gets a gentle note.
  • A fractional head count is rounded down with a message; zero or negative people is refused.
  • Sats mode rounds a fractional bill to the nearest whole sat and says so.
  • Very large groups collapse the list into a summary line to keep the window readable.
A bill bar and a tip bar are added together, then divided into equal shares. The first share carries one extra unit when the total does not divide evenly. bill tip share share share +1
Tip splitter: the idea in one picture.

Stacking planner

Open on the desk

What it does

Projects how many sats a recurring purchase would add up to, using an amount, an interval, a duration and a rate you assume. It is a what-if calculator for planning a habit, and it draws a small chart and a table of checkpoints so you can see the shape of the plan.

How to use it

  1. Type what you plan to spend each time and choose the interval: day, week, two weeks or month.
  2. Set how long the plan runs, in months or years, and type the price of 1 BTC you want to assume.
  3. Open the optional section to add a percentage fee per purchase or a monthly drift in the assumed rate.
  4. Read the projected stack, the average price paid and the checkpoint table. Use converter rate copies the rate from the converter.

Assumptions

  • One purchase happens at the end of each completed interval. A month is 30.4375 days, which is a year of 365.25 days divided by twelve.
  • A fee is taken out of each purchase before the remainder buys sats, and each purchase buys whole sats (rounded down).
  • Drift compounds monthly and applies to the assumed price, so a negative drift buys more sats later.
  • Nothing here predicts a price. If the numbers look attractive, that is your assumption talking.

Edge cases

  • A duration shorter than one interval means no purchase happens, and the tool says so instead of showing zero.
  • Zero or negative amounts, rates and durations are refused with an explanation. Plans longer than fifty years are refused.
  • A drift that would push the price to zero or below is caught before it produces nonsense.
  • Results that would overflow ordinary numbers are reported as too large.
A bar chart of cumulative sats rising step by step, one step per purchase, along a time axis. purchases over time sats
Stacking planner: the idea in one picture.

Base converter

Open on the desk

What it does

Converts unsigned integers between decimal, hexadecimal and binary using arbitrary-precision arithmetic, so a 256-bit hash fragment is as easy as a byte. Alongside the three boxes it shows bit length, byte length, the 8-byte little-endian form used for amounts in transactions, and the same number read as satoshis.

How to use it

  1. Type or paste a value into any box. Prefixes 0x and 0b are accepted, and spaces or underscores are ignored.
  2. Use the example chips for common sizes: a byte, 2^32, the cap in sats, or the largest 64-bit value.
  3. Read the extra lines for the width of the number and its little-endian bytes.

Assumptions

  • Values are unsigned whole numbers. There is no sign, fraction or fixed-width wrap-around.
  • Hex is shown in lowercase without a prefix so it is easy to paste elsewhere. Binary is grouped in fours for reading.
  • The little-endian line is only shown when the value fits in eight bytes.

Edge cases

  • Each box names the first character it cannot accept, for instance a 2 in the binary box.
  • Negative numbers are explained, not silently flipped.
  • Inputs beyond 1,024 bits are refused with the limit stated.
  • The satoshi reading above the 21 million BTC cap is labelled as beyond the supply cap.
The same number written three ways: decimal 255, hexadecimal ff, binary 1111 1111. dec255 hexff bin1111 1111
Base converter: the idea in one picture.

Notes

Open on the desk

What it does

A plain-text scratchpad that saves as you type. It is meant for the small things that go with these tools: a rate you want to remember, a checklist for a transfer, a label draft. It can also save a copy as a text file or print the note.

How to use it

  1. Type in the note. It saves a moment after you stop, and the status line shows when.
  2. Choose Save .txt to download a copy, Print for paper, or Clear to erase it (with a confirmation step).
  3. Close the window whenever you like; the note stays.

Assumptions

  • The note lives in your browser's local storage, on this device and in this browser profile only.
  • Clearing site data, using a private window or switching browsers means the note will not be there.
  • It is plain text: no formatting, no sync, no sharing.

Edge cases

  • If storage is blocked, the note still works and says it is held in memory until the tab closes.
  • Very large notes may hit the browser's storage limit; the status line then says the note could not be saved.
  • Do not keep seed phrases, private keys or passwords here. Local storage is not a vault.
A note page with text lines, an arrow, and a box labelled this browser. The note is saved there and goes nowhere else. thisbrowser
Notes: the idea in one picture.

Reference card

The handful of Bitcoin facts the desk leans on. They are long-established and unchanging, which is why they are the only ones printed here.

Unit
1 BTC is 100,000,000 satoshis. A satoshi is the smallest unit the desk handles.
Supply cap
21 million BTC, which is 2,100,000,000,000,000 sats.
Block interval
About ten minutes by design. It is a target, not a promise for any single block.
Halving cycle
The block reward halves every 210,000 blocks, roughly four years at the target interval.
Proof of work
SHA-256 hashing secures the chain.
Coin model
UTXO: outputs are spent whole, and change comes back as a new output.
Origins
The whitepaper was published in 2008 and the genesis block was mined in January 2009.
Prices
Deliberately absent. Rates in these tools are yours.

Pocket Desk is independent. It is not affiliated with, endorsed by or a client of any wallet, exchange, company or Bitcoin software project.