Thermal Label Sizes Explained: 4×6, 3×2, 2×1 — Which Should You Buy?

Thermal labels come in standardized sizes — but "standardized" hides the fact that there are at least 12 common sizes you will encounter in eCommerce and retail. This guide catalogs the ones that actually matter for online sellers.

The eCommerce shipping label size: 4×6 inch (100×150mm)

The dominant size for shipping labels worldwide. Every major Indian marketplace (Amazon, Meesho, Flipkart) and every major courier (Delhivery, BlueDart, Ekart, XpressBees) accepts 4×6 inch thermal labels. If you buy any other size for shipping, you are creating compatibility problems for yourself.

What it costs

• Per roll (1,000 labels): ₹450–₹600.
• Per label: ₹0.45–₹0.60.
• Adhesive grade: General-purpose acrylic; some sellers prefer all-temp for cold-chain shipments.

Reference: common thermal label sizes

Size (in)	Size (mm)	Primary use	Per-roll capacity
4×6	100×150	Shipping labels (Amazon/Meesho/Flipkart)	500–1,000
4×4	100×100	Compact shipping (small parcels, FBA boxes)	700–1,200
4×3	100×75	Lightweight envelopes, cosmetics	1,000–1,500
3×2	75×50	Product labels, batch labels	1,500–2,500
2×1	50×25	Asset tags, bin labels, jewelry	3,000–5,000
2.25×1.25	57×32	Retail price labels, shelf tags	2,500–4,000
1.5×0.5	38×13	Cable labels, small accessories	5,000–10,000

4×6 vs 4×4 — does the saving matter?

Some sellers shipping small items (jewelry, supplements, accessories) consider 4×4 labels to save 33% on label cost. Two issues:

• Marketplace PDFs are formatted for 4×6. You'd need to crop the bottom of the label, potentially losing the QR or DataMatrix.
• Couriers rarely complain about a "too big" label, but a "too small" label that lost the DataMatrix gets rejected at the hub.

Stick with 4×6 unless you are willing to test extensively per courier per region.

Roll core and roll diameter

Every label roll has two key dimensions beyond label size:

• Core diameter — usually 25mm or 76mm (1" or 3"). Most desktop printers use 1" core; floor-standing models use 3".
• Outer diameter — limited by the printer's roll holder. Desktop printers cap at ~5" OD (1,000 4×6 labels).

Direct thermal vs thermal transfer

A common confusion: direct thermal labels darken when heat is applied (no ribbon needed, fade over years). Thermal transfer labels need a separate ribbon (carbon film) and produce permanent prints that don't fade.

• For shipping labels (life ≤ 1 month): direct thermal is perfect.
• For product labels exposed to sun, oil, or chemicals: thermal transfer.
• For cold chain (frozen goods): special freezer-grade direct thermal.

Choosing a printer to match? See the thermal printer buying guide for Indian sellers.

What about A4 with 4-up labels?

A4 sticker sheets pre-cut into 4 quadrants are popular with sellers who don't yet have a thermal printer. Each "label" is roughly 4×6 inches when rotated. The cost is ~₹2.20 per label vs ₹0.45 thermal — roughly 5× more expensive per label.

The Ecom Insides cropper supports A4 1-up, 2-up, and 4-up output for sellers still on laser printing, but recommends thermal for any seller above 30 orders/day.