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The invoicing math, without the spreadsheet nightmare.

The engine behind our quotes and invoices: profit, margin, tax, currency, ROI — worked out on one screen, saved automatically, and ready to share.

31 currencies · 7 tax regions · Built inside NTJ · Runs in your browser
06 calculators · one workspace

The math your business actually does

Each tool is a single screen. No setup, no schema, no "connect your data source." Type the numbers. Read the answer.

F-01

Profit calculator

Revenue minus everything else. Margin, breakdown, and projections sit on one screen. Flip between gross and net, monthly and annual, with tax or without.

7cost categories·12moprojection
F-02

Tax calculator

VAT, sales tax, GST — you set the rate for the region you're billing. Go net to gross, gross to net, or get a clean line-by-line breakdown for your invoice.

7regions preset·manualrate entry
F-03

ROI calculator

Money in, money out. Period and discount rate are optional. You get your break-even charted, down to the exact month you cross it.

IRR+ NPV·break-evenhighlighted
F-04

Currency converter

31 currencies on mid-market rates. Switch to a bank spread or type your own rate. Every conversion gets dated and saved, so you can prove the rate you used later.

31currencies·mid-marketdefault
F-05

Saved scenarios

Put what-if-we-hire, what-if-recession, and your base case side by side. Tag them, pin them, diff them. Nothing gets lost.

unlimitedsaves·3-upcompare
F-06

Audit trail

Who changed what, when, and from what value. Every input is timestamped, and you can roll back to any earlier version in one click. Your accountant will thank you.

↑žhistory·1-clickrestore
live · interactive

See it calculate

An actual BlinkCalc profit screen, embedded right here. Change a number — watch every other number react.

SESSION · profit-calc · live
profit=revenue(cost + ads + employees + tax)
USD
USD
USD
USD
Tax estimated at 21% on pre-tax profit · adjust region in app
Pre-tax profit
revenue − costs
$27,100
Tax estimate · 21%
on positive pre-tax profit
$5,691
Net profit · monthly
what actually lands in the bank
$21,409
Net margin
healthy · above 20% target
25.3%
last edit just now · 4 inputs · 4 outputs · $256,908/yr projected
under the hood

How BlinkCalc thinks

Three steps. The same three steps your accountant takes — only the keystrokes are yours and the spreadsheet doesn't exist.

01
Inputs
Type the four numbers you actually know. The rest come from the rate you've set for the region.
revenue 84,500
cost 32,400
ads 6,800
payroll 18,200
02
Formula
A transparent equation. Not a black box. Click any variable to swap in your own rate or region.
subtract costs
apply tax rate
annualize ×12
project 12mo
03
Insights
Net profit, margin band, projection, breakdown — every result with a link back to its formula.
net profit 21,409
margin 25.3%
annual 256,908
breakeven mo 4
profit = revenue (cost + ads + employees + tax)
who's calculating

Built for people who hate spreadsheets

Not for FP&A teams with a Bloomberg subscription. For the actual humans running the business.

USE-01 · retail

Shop owners

Know your real profit on every product, not just gross sales. See which SKU pays your rent and which one is quietly bleeding margin.

margin per SKU · landed cost · weekly net typical setup time · under 4 minutes
USE-02 · services

Freelancers & consultants

Set your rate. See your real hourly after tax, software, and that "quick" admin you never bill for. Adjust before sending the quote.

effective rate · quote builder · tax-aware typical scenario · "is this project worth it?"
USE-03 · small teams

Small finance teams

Model "what if we hire" or "what if revenue drops 20%". Save it. Share it. Compare three scenarios in one view, board-ready.

3-up scenario diff · share link · CSV out typical user · founder + part-time CFO
a saved scenario, expanded

What you get when you save

Not just numbers — a snapshot. Everything that went into the calculation, frozen in time, with a paper trail.

Sample data — illustrative only
Q4 · what-if we hire 2 designers
last modified May 12 · 14:08 UTC · by @maya · v.3
what-if hiring Q4-2026 design
revenue$92,000
cost of goods$33,800
ads$7,200
payroll (+2)$28,400
tax rate21.0%
regionUS-DE
$17,066
net monthly · margin 18.5% · annualized $204,792
net profit · projection $204,792 annual
14:08:42 @maya changed payroll 24,000 → 28,400
14:04:11 @maya added tags hiring, design
13:58:02 @dan duplicated from Q4 · base case
May 11 @dan created scenario
scenario-id · scn_8f4c2e1b
geo · taxes · currencies

Built for international small businesses

Tax rates and FX rates you set once, then reuse. If you invoice across borders, the math doesn't break at the border.

US sales tax UK VAT DE EU VAT CA GST + PST AU GST SG GST FR TVA ES IVA IT IVA NL BTW IE VAT SE Moms CH MWST JP CT IN GST + 15 more →

Rates are configured by whoever runs the calculation · each result is stamped with the rate and date it used · BlinkCalc does the arithmetic, not the tax research · not tax advice

interop · the rest of the stack

BlinkCalc plays well with your tools

Pipe in cost-per-customer from Crewix. Pull margin-per-product from PopCart. Drop in campaign ROI from Flowly. Or just import a CSV and walk away.

CX
Crewix
cost per customer · CAC sync
PC
PopCart
margin per product · SKU feed
FL
Flowly
campaign ROI · attribution
.c
CSV in/out
drag · drop · done
$
Stripe sync
revenue, fees, refunds → BlinkCalc
soon
FAQ · the five we get most

Reasonable questions, direct answers

Q-01 Where do the tax rates come from?
From whoever sets them up. BlinkCalc doesn't maintain a rate database and doesn't monitor rate changes — the rate for each region is configured by hand. Each calculation is stamped with the rate and the date it used, so you can see afterwards what was applied. Check the rate against your own source before relying on it.
Q-02 Can I share a scenario with my accountant?
Yes. Every scenario has a "Share" action that generates a read-only link. Your accountant doesn't need an account to view inputs, results, the formula, and the audit trail. You can revoke the link any time, and shares are logged with view timestamps.
Q-03 Does it support my country's VAT?
There are presets for seven regions — United States, United Kingdom, European Union, Canada, Australia, Singapore, and Japan. They're a starting point, not a verified ruleset, so check the rate before you use it. Any other region works the same way: enter your own rate, label it, and BlinkCalc treats it identically.
Q-04 What if my numbers are sensitive?
Calculations run in your browser — nothing leaves your device unless you save a scenario, and even then it's encrypted at rest. We never train models on your financial inputs. You can enforce SSO, set data residency (US/EU), and export every scrap of your data on demand.
Q-05 Is this tax advice?
No. BlinkCalc does arithmetic on the numbers and rates you give it. It doesn't check that a rate is correct for your situation, doesn't track legislation, and isn't a substitute for an accountant or a tax adviser. Before you invoice or file on the strength of a figure from here, have someone qualified check it.
the N.T.J ecosystem

Other tools from N.T.J

Same design language. Same vibe. Different jobs.

ntj labs

Explore more technologies built inside NTJ.

BlinkCalc is one of the tools our team built to run marketing operations and client delivery. The rest of NTJ Labs is worth a look too.

Features in depth

Everything BlinkCalc does.

The business math you actually need, worked out in a few clicks and saved as you go — no spreadsheet required.

Profit calculator

Enter revenue and costs to see gross and net profit laid out line by line.

Tax breakdown (7 regions)

Apply the rate you've configured for any of seven preset regions and see the split before and after tax.

Margin analyzer

Check gross and net margin on a price or a whole product line at a glance.

Currency converter (31 currencies)

Convert figures across thirty-one currencies without leaving your calculation.

ROI scenarios

Model the return on a spend and compare a few what-ifs side by side.

Break-even calculator

Find the point where sales cover costs, based on your price and fixed outlay.

Investment forecast

Project how a sum grows over time at a rate and interval you set.

Loan calculator

Work out monthly payments, total interest, and the full schedule for a loan.

Discount and markup tool

Add a markup or take a discount and see the resulting price and margin.

Multi-scenario comparison

Line up several versions of a calculation and read the differences in one view.

Save + share reports (PDF)

Save any calculation and export it as a PDF to send on to whoever needs it.

Team collaboration on calculations

Share a calculation with your team so everyone works from the same numbers.

Use cases

How we use BlinkCalc.

Scoping a piece of client work

Our team runs cost, markup, and margin together to settle on a figure for a proposal. Scenarios are saved so the assumptions can be revisited later.

Billing an overseas client

An account manager converts the invoice into the client's currency and applies the tax rate set for that region. The finished breakdown goes out as a PDF the same afternoon.

Weighing up a spend

An operations lead models the ROI and break-even for a spend across a few scenarios. The comparison view makes the trade-offs easy to talk through in a meeting.

Built inside NTJ

This technology was developed inside NTJ to support marketing operations, automation, analytics, and client delivery. Availability may vary depending on the product and use case.

Some NTJ technologies are used internally, some are made available to selected clients, and others may be released publicly. This technology is not the primary service offered by NTJ — our core focus is helping businesses achieve measurable growth through better marketing.

Talk to us about your marketing needs →

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Scenario saved. scn_····