Ink · Calculator

Flexo ink consumption calculator

Work out how much ink a flexo job needs, per colour, from print area, coverage, anilox volume and run length. Type your numbers in below; nothing to sign up for.

Your job

Filled in with the worked example further down. Change any number and the answer updates.

Print width (mm)Across the web

Repeat length (mm)Around the cylinder

Impressions (worked out)From the order above: prints of the full repeat

SubstratePaper takes more ink than film

Press settings (house defaults)

Anilox transfer (%)Share of the cell volume that reaches the substrate

Anilox unitApplies to every colour below

Start-up web (m)Printed while getting to colour

Make-ready ink (kg per colour)Fills the chamber, anilox and lines

ColourCoverage (%)Anilox

Ink for the run

Start-up and make-ready

Total to have on hand

Colour	Laydown g/m²	Ink for the run	Start-up and make-ready	Total	g per metre

How to calculate ink consumption in flexo

Every flexo ink estimate comes down to one line: how many square metres get printed, how much of that each colour covers, and how many grams of ink land on each square metre it covers.

Ink (g) = printed area (m²) x coverage x laydown (g/m²)
Laydown = anilox volume (cm³/m²) x transfer x substrate factor

Work it out one colour at a time:

Printed area. Width x repeat length gives the area of one impression. Multiply by the number of impressions. Convert millimetres to metres first (330 mm is 0.33 m).
Coverage. The share of that area the colour actually prints, as a fraction (25% is 0.25). A solid background might be 80%; a small logo spot might be 3%.
Laydown. The anilox cell volume tells you how much ink the roller carries. Only part of it reaches the substrate, so multiply by the transfer rate. Absorbent paper drinks a little more than film, so multiply by the substrate factor.
Grams, then kilos. Multiply the three together for grams; divide by 1,000 for kilograms. Ink weighs close to 1 g per cm³, so cm³ of ink and grams of ink are near enough the same number.
Add the ink you need before the first good print. The web you run getting to colour, and the ink it takes to fill the chamber, anilox and lines.

What the calculation needs

Coverage. The percentage of the printed area each colour covers. This is the number people most often guess, and the one that moves the answer most. More on that below.
Print area. Width across the web and repeat length around the cylinder, plus the number of impressions. If the plate carries several labels across and around, count impressions of the whole repeat, not individual labels.
Anilox volume. The cell volume of the anilox roller for that colour, in cm³/m² or BCM. Line work and process colours often run 3 to 4 cm³/m²; solids and whites run 6 to 10 or more. 1 BCM is 1.55 cm³/m².
Transfer rate. How much of the cell volume actually leaves the anilox and reaches the substrate. Around 40% is a sensible starting point; your press, plate and ink will move it. If you have measured yours, use it.
Number of impressions. The run length. Add the start-up metres separately so they are not hidden inside the order quantity.

If a colour has no anilox entered, the calculator falls back on a rule of thumb of 3.5 g/m² at a solid, adjusted for the substrate. That is roughly what a standard 8 to 10 cm³/m² roller lays down at 40% transfer, so the two methods agree.

Worked example

A five-colour paper label: 330 mm wide, 254 mm repeat, 20,000 impressions, house defaults of 40% transfer, 50 m of start-up web and 0.5 kg make-ready per colour. Paper label, so the substrate factor is 1.2. This is the job already filled in on the calculator above.

Step 1, printed area. 0.33 m x 0.254 m = 0.08382 m² per impression. x 20,000 = 1,676.4 m².

Step 2, laydown for PMS 485 on a 6 cm³/m² anilox: 6 x 0.40 x 1.2 = 2.88 g/m².

Step 3, ink for the run. 1,676.4 m² x 0.12 coverage x 2.88 g/m² = 579.4 g, so 0.58 kg.

Step 4, start-up and make-ready. 50 m x 0.33 m = 16.5 m² of start-up web. 16.5 x 0.12 x 2.88 = 5.7 g, plus 0.5 kg make-ready = 0.51 kg.

Step 5, total. 0.58 + 0.51 = 1.09 kg of PMS 485. The same sum for every colour:

Colour	Coverage	Anilox cm³/m²	Laydown g/m²	Run	Start-up + make-ready	Total
Cyan	32%	3.5	1.68	0.90 kg	0.51 kg	1.41 kg
Magenta	28%	3.5	1.68	0.79 kg	0.51 kg	1.30 kg
Yellow	25%	3.5	1.68	0.70 kg	0.51 kg	1.21 kg
Black	18%	3.0	1.44	0.43 kg	0.50 kg	0.94 kg
PMS 485	12%	6.0	2.88	0.58 kg	0.51 kg	1.09 kg
All colours				3.41 kg	2.53 kg	5.94 kg

Notice that on a short run the make-ready ink is close to the run ink itself. That is normal, and it is why small jobs cost more ink per label than long ones.

Working from kilos of film

Flexible packaging is often ordered by weight: "200 kg of PET/PE laminate". The ink sum needs impressions, so the kilos are turned into square metres, metres of web and impressions first. Choose Order in kg on the calculator and it shows this working as you type. Here it is with a pencil, for a PET 12 / PE 50 laminate, 2.5 g/m² adhesive, 330 mm web, 254 mm repeat:

Weight of one square metre (gsm). Each layer is thickness in microns x density: PET 12 x 1.39 = 16.68, PE 50 x 0.92 = 46. Add the adhesive: 16.68 + 46 + 2.5 = 65.18 g/m².
Square metres. 200 kg is 200,000 g. 200,000 / 65.18 = 3,068 m².
Metres of web. 3,068 / 0.33 m = 9,298 m.
Impressions. 9,298 / 0.254 m = 36,607. From here the ink is worked out exactly as in the example above.

The trap: the kilos are the weight of the whole laminate, so the gsm must be the whole laminate's. Using only the printed film (PET 12 = 16.7 g/m²) gives about 11,990 m², close to four times too much ink. A single film is simpler: 200 kg of 20 micron BOPP at 0.91 is 18.2 g/m², 10,989 m², 33,300 m of web and 131,102 impressions.

The densities on the calculator are typical values. Use the figures from your material spec sheet when you have them, or type the total gsm straight in. Ordering in labels or bags instead? Choose Order in units and give how many each impression prints: 100,000 labels on an 8-up plate is 12,500 impressions.

Why a spreadsheet often gets this wrong

The formula is simple, which is exactly why home-made sheets drift. The usual slips:

BCM typed into a cm³/m² formula. The answer comes out 35% too low, because 1 BCM is 1.55 cm³/m².
Full cell volume, no transfer. Assuming everything in the cell lands on the substrate more than doubles the ink.
Coverage of the label, applied to the whole sheet. If the label is 40% covered but only fills 80% of the repeat, the colour covers 32% of the printed area, not 40%.
Labels counted as impressions. On an 8-up plate, 20,000 labels is 2,500 impressions. Counting labels gives eight times the ink.
No start-up or make-ready. The run figure on its own is never what you need on the press. On short runs it can be half the total.
Millimetres and metres mixed. One missing divide by 1,000 and the sheet orders a tonne of ink.

The Excel version below has each of these built in, with the working shown cell by cell, so it is easy to check against your own sheet.

Download the Excel versionSame formula as the calculator above. No sign-up.

Ink coverage from a PDF

Coverage is the honest starting point, and the weakest number in most estimates. Eyeballing a proof and calling the background "about 60%" can easily be out by 15 points, and every point of coverage is a point of ink.

The reliable way is to measure it from the separations: render each plate of the print-ready PDF, count the inked area, and divide by the area of the repeat. Halftones count at their tone value, so a 50% tint over a quarter of the label is 12.5% coverage, not 25%. White and varnish count too, and are often the biggest consumers on a film job.

Drop a PDF and it reads the coverage for you, in the full tool (7 day trial, no card). The figures it measures go straight into the same calculation as this page, so the two always agree.

Questions

How much ink does a flexo job use?

Printed area times coverage times ink laydown. A typical label job on a 3.5 cm³/m² anilox lays down about 1.7 g of ink per square metre of solid on paper, so 1,000 m² at 30% coverage uses about half a kilo of that colour, before start-up and make-ready ink.

What is the difference between BCM and cm³/m²?

Both measure anilox cell volume. BCM is billions of cubic microns per square inch; cm³/m² is the metric unit. 1 BCM is 1.55 cm³/m². Pick the unit you have and the calculator converts it.

How do I work out ink from kilos of film?

Turn the kilos into square metres first: the weight in grams divided by the gsm of the whole material, every layer plus the adhesive. 200 kg of a PET 12 / PE 50 laminate at 65.18 g/m² is 3,068 m², which is 9,298 m of a 330 mm web or 36,607 impressions on a 254 mm repeat. Choose Order in kg on the calculator and it does this for you, then works out the ink as normal.