Draftply — Skip the script. Draft the answer.

See it

In action

See it work — about half a minute each.

Why not a spreadsheet

Everyday maths

Too much for a calculator. Too little for a spreadsheet.

Most real-life maths lives in between: one question, a handful of numbers, an answer you want to trust — and still understand next year.

01

Nothing to set up. Nothing to learn.

Write it the way you would say it. Watts times hours times price comes out in euros — the units do the converting. No /1000, no cell references, no layout to build first.

Spreadsheet=B2*C2*365/1000*D2

draftply

fridge.dply

11500 W * 4 h * 365 * 0.30 €/kWh657 €

02

Still makes sense next year.

Every line says what it is. Open it again next spring or hand it to someone else — nobody has to work out what a formula once meant.

Spreadsheet=(C4*C5/100*C6+C7)/12What was C5 again?

draftply

car.dply

1// What the car costs per month

2fuel = 12000 km * 6.5 L/100km * 1.80 €/L1,404 €

3insurance = 800 €800 €

4Per month: (fuel + insurance) / 12Per month:183.67 €

03

Every step stays.

The calculator on your phone keeps only the last number. Here every step stays on the page — change one, and everything below follows.

Calculator153.605…and how did you get there?

draftply

weekend.dply

1hotel = 3 * 140 €420 €

2fuel = 2 * 380 km * 7 L/100km * 1.85 €/L98.42 €

3tickets = 4 * 24 €96 €

4Each of us: (hotel + fuel + tickets) / 4Each of us:153.61 €

Real questions

Sound familiar? The answer is ready.

Each one is a template in the sample library: open it, put in your own numbers, done. Nothing to learn first.

Runs live

For your field

Amateur radioImpedance, SWR, link budgets — eighteen ready-made calculators, free.Trades & freelancersDraft the quote as you think it through, hand the client a PDF.School & universityUnits, solve(), derivatives and plots — the working stays on the page.If you codeYou could script it. Why an exact, unit-aware notepad is often the faster way.

Why "draft"

A draft isn't the cathedral. It's the working answer — built fast, good enough to act on, easy to hand to the next person.

This started because a decimal point in the wrong place kept breaking the flow. No appetite for a heavyweight spreadsheet, no time to write a script. So: a notepad that does the math, keeps every step in view, and lets you pass the whole thing on. Need the polished, high-performance version later? Rebuild it in a full programming language. For everything in between — draftply.

Module 01 — Draft

A question in your head. Start typing.

No setup, no boilerplate. Open it, type your numbers, label your values, drop in a formula. Like scribbling on a notepad — except every line is solved the instant you write it.

Units4.5 m * 12 m → 54 m²

Percent1200 * 80% → 960

Valuesstay around — reuse them three lines later, or thirty.

budget.dplyEditor

1Income = 3,2003,200

2Rent = 1,1501,150

3Food = 480480

4Left: Income - Rent - FoodLeft:1,570

5Saved: @4 * 40%Saved:628

6

Module 02 — Solve

analysis.dplyEditor

1class Growth(p, rate):→function defined

2 def after(yrs):

3 return self.p * (1 + self.rate)^yrs

4inv = Growth(10,000, 0.07)Growth(…)

5round(inv.after(10), 2)19,671.51

6solve(y^2 - 5*y + 6 == 0, y)y = 2, y = 3

7

When arithmetic isn't enough, go deeper.

The language grows with the question. Functions, classes, loops, matrices, statistics, symbolic algebra — all solved live, all in the same document. No imports, no environment, no debugging cycle.

Structurefunctions and classes that read like your thinking

Algebrasolve simplify factor, derivatives, integrals

Datamean std det inv — built in

Module 03 — Plot

Numbers have a shape. Draw it.

One line asks for a chart, and it appears in the result column next to that line — redrawn the moment a number above it changes. Pass a named list and every curve gets its own colour and a legend entry. Hover to read exact values; one click takes the chart out as an image or as data.

Kindsplot scatter bar hist pie surface

Series["3 %": a, "7 %": b] — a curve or bar group each, with a legend

ExportPNG with legend, SVG, or the values as CSV

savings-rates.dplyEditor

draftply editor: a savings function evaluated at 3 % and 7 %, and one plot line drawing three labelled curves with a legend in the result column

Module 04 — Form

investment-check.dply Form

draftply form view of an Investment Check — amount, years, strategy and tax chips, with future value, gross gain and net gain computed live

Give the solution a front panel.

Solved is solved. Add a header block and the document turns into a form: labeled inputs, chip selectors for fixed choices, protected outputs. One switch between editor and front. Nothing is hidden — the math is one toggle away — the form just means nobody has to look at it to get an answer.

Inputtext fields that recalculate as you type

Choicechips for strategy, tax rate, variant

Outputprotected — nothing to break

Sectionsfold a long form into named, collapsible groups

SwitchForm → Form view flips between editor and form

Module 05 — Hand off

Pack it. Send one file.

A .dplybundle packs your document and its libraries into a single file. Whoever opens it sees the form, fills in their own numbers, gets their own answer. If they're curious, the plain text is right there — read it, change it, make it theirs.

Contentsdocument plus libraries, together

Substanceplain text underneath, open to inspect

Transportmail, drive, USB — no server, no account

investment-check.dplybundleOne file. Everything inside.

Module 06 — Quote

Your Company Offer
2026-09-18

Coleman
Customer Street 1
00001 Customer City

ItemAmount

Tiling360.00 €

Material320.00 €

Total680.00 €

plus 19 % VAT129.20 €

Total amount809.20 €

Draft it. Hand them the quote.

Line items, a running total, a couple of recognized fields like CustomerName or VatRate — done thinking about it. File → Export offer turns the exact same document into a client-ready PDF — your letterhead on top, a clean item table below, nothing scratch left in. Need the numbers instead of the document? Export offer as CSV writes the same rows — VAT breakdown included — as plain semicolon-separated values for your own spreadsheet.

Itemslabeled lines become rows, total becomes the sum

VATset VatRate and the total row splits into net, VAT and gross — automatically

Letterheadyour company details, or your own header image/PDF

Left outunlabeled math, comments, charts — never printed

Module 07 — Side window

Pull it narrow. Keep it beside you.

Below 600 pt of width, draftply folds the result column away and puts each answer at the end of its own line. Park a slim window next to your browser, IDE or spreadsheet and do the side math without switching. Everything else stays the same — charts, forms and offer export included.

Triggeronly the width counts — tall or short, it stays compact

Per draftView → Three columns brings the columns back for one draft

Gesturestap a result to jump to its line, hold it to copy

quick-checks.dplyCompact

draftply in a 480 pt window: meeting cost, commute, fuel and coffee, each result shown at the end of its own line

Module 08 — Note

Just write. The math stays out of the way.

Note mode shrinks draftply to a narrow note that stays on top while you work somewhere else. There's no result column: each answer appears faintly right behind its own line, and a calculation in braces is answered mid-sentence. On phones and tablets, note mode is the alternative to the compact view — whichever you like better.

SwitchView → Note mode, or Ctrl + Shift + M

Desktopa 380 pt note, always on top — the pin lets it drop behind

Phonetap a result to jump to the end of its line, hold it to copy

Quiethalf-written sentences and errors stay silent; free and Pro

travel.example/lisbon-weekend

Lisbon · Fri 14 – Mon 17 Nov · 2 travellers

Your weekend, 3 nights

✈ BER ⇄ LISreturn, hand luggage 89 €per person

⌂ Guesthouse in Alfamadouble room, breakfast 142 €per night

☕ Eating outtascas and pastelarias ≈ 25 €per person a day

lisbon.dplyNote

1Weekend in Lisbon, {n = 3} nights

2flights = 2 * 89 € = 178 €

3hotel = n * 142 € = 426 €

4food = n * 2 * 25 € = 150 €

5trip = flights + hotel + food = 754 €

6That makes {trip / 2} → 377 € each.

7

Sample library

Start from a working answer

70 samples. Already in the app.

Budgets, loans, road trips, recipes, antenna lengths — every sample on this site also ships inside draftply. File → Sample Library, no network needed: open one, change the numbers, keep what you need.

Basics & Reference3 samples Standard Libraries5 samples Showcase2 samples Finance & Savings8 samples Living & Real Estate6 samples Mobility & Transport6 samples Household & Daily Life15 samples Advanced Math & Functions6 samples Amateur Radio & RF Engineering18 samples Bundles & Libraries1 sample

Browse all samples →

Spec sheet

Under the hood

Not a fancy calculator. A real language.

Evaluationevery line in a background isolate, the interface never freezes

Interpreterlexer, parser, evaluator — variables, functions, classes, control flow

Algebrasolve, simplify, factor, derivatives, integrals, polynomial CAS

Matricesdet, inv, transpose, trace, norm; arrays with sort, range, push

UnitsSI with prefixes, currencies, convert(); your own units via defunit()

Statisticsmean, median, std, mad, cumsum, nCr, gcd; percentages as 80%

Chartsline, scatter, bar, histogram, pie — several series with a legend; export SVG, PNG, CSV

Datesdate and datetime arithmetic; calendar and time pickers in forms

Randomnessrand() and randi() hold still until you edit the line — reroll with the dice

Stringsfirst-class text with interpolation: "Total: {x + y} €"

PrintPDF in two columns, code and result side by side

Numberscomma or period, grouping, precision, font — your call

Availability

Editions

Free where it starts. Pro when you need more.

On Apple, Android and Windows (Microsoft Store), start free and try every Pro feature free for 7 days — one Pro purchase on Apple unlocks iPhone, iPad and Mac together. Linux is currently free — no trial, no purchase required.

Pro is a one-time purchase, no subscription: €14.99 on Apple (iPhone, iPad and Mac together), €12.99 on Windows and Android. Store prices can differ by country and local taxes.

iOS · macOS Windows AndroidSoon LinuxSoon

Start with the question.
Hand off the answer.

See it work — about half a minute each.

Too much for a calculator. Too little for a spreadsheet.

Nothing to set up. Nothing to learn.

Still makes sense next year.

Every step stays.

Sound familiar? The answer is ready.

When can I leave today?

What is this meeting costing?

What does the old fridge cost me per year?

Am I really working overtime?

Is the cheaper gas station worth the detour?

Is my share of the utility bill right?

How much paint and flooring do I need?

Is a back-payment on my power bill coming?

The recipe serves 4. You're cooking for 7.

Is the big pack actually cheaper?

What does my car really cost per month?

When does the solar roof pay for itself?

What does carpooling save each of us?

Charging at home or at the station?

What will the move really cost?

Can we afford two weeks away?

Which flat is the better deal?

What would quitting smoking save me?

What will 1,000 € be worth in ten years?

A question in your head. Start typing.

When arithmetic isn't enough, go deeper.

Numbers have a shape. Draw it.

Give the solution a front panel.

Pack it. Send one file.

Draft it. Hand them the quote.

Pull it narrow. Keep it beside you.

Just write. The math stays out of the way.

70 samples. Already in the app.

Not a fancy calculator. A real language.

Free where it starts. Pro when you need more.