Find the right rubber bands and elastic bands for stationery, paperwork, stock bundles and boxes. Understand size numbers, measure an existing band and compare the options available from AOS Online.
The key measurement: rubber band length normally means the unstretched flat length. A 150 mm band has an approximate relaxed loop circumference of 300 mm. It is not a 150 mm diameter loop, and 150 mm is not its maximum stretched length.
How are rubber bands measured?
1. Measure the flat length
Lay the band flat, bring the two sides together and measure from one end to the other without stretching it. Use millimetres for easy comparison with product listings.
Approximate relaxed circumference = flat length × 2. For example, a 76.2 mm flat band has a relaxed circumference of about 152.4 mm.
2. Check the width
Measure across the rubber strip, perpendicular to its length. In a listing such as 152.4 × 3.2 mm, the first figure is the flat length and the second is the band width.
3. Do not confuse width with thickness
Wall thickness is the depth of the rubber material itself. It is a separate measurement and is not necessarily supplied in a two-number product description.
Replacing a band that already works? Match its unstretched length and width first, then check the material and intended use. A stretched, cracked or permanently elongated old band is a poor measuring template.
Rubber band sizes: compare length and width
This chart uses dimensions published for the Q-Connect products listed by AOS. The shopping column also links to the matching size numbers from White Box and 5 Star where listed. Compare each product’s stated dimensions before ordering; dimensions and pack weights vary by brand.
Check the dimensions as well as the size number. Brand conventions and rounding can differ. For example, the AOS Q-Connect No.12 listing states 38.1 × 1.6 mm; other manufacturers may use No.12 for a different length. This is a product-specific chart, not a universal standard.
On a small screen, scroll the table sideways to see the shopping links. Circumferences below are calculated approximations, not maximum stretch ratings.
Other sizes and brands: the wider category also includes numbered bands from 5 Star and White Box, plus assorted and X-band options. Where a listing does not give dimensions, ask us to confirm them before choosing for a precise fit. Browse the complete rubber band range.
How to choose a band for your item
Measure the route the band will actually follow. Wrap a piece of string or a flexible tape around the item, including its thickness. Keep the item in its finished, bundled shape.
Compare that route with twice the band’s flat length. A band needs some tension to grip, but the amount of stretch it can safely tolerate depends on the particular product.
Choose the width to suit the contents. A wider strip spreads contact over more surface. Holding force also depends on material, thickness and stretch; width alone does not guarantee strength.
Trial the fit before buying in quantity. The band should hold securely without crushing a box, curling paperwork or requiring excessive force to fit.
For a rectangular bundle: approximate loop route = 2 × (the side you are going around + bundle thickness). For a round bundle, route ≈ diameter × 3.14. String gives a useful check for rounded corners or irregular shapes.
What size rubber band do I need? Everyday examples
These are worked measuring examples, not guaranteed fit recommendations. Measure your own item and trial the band: box dimensions, rubber formulation and holding tension all matter.
A rubber band around a shoebox
Take an example box measuring 330 mm long × 200 mm wide × 120 mm high. To hold the lid down with a band running across the shorter direction, measure around the width and height.
2 × (200 + 120) = 640 mm around the box. Running the band the other way needs about 2 × (330 + 120) = 900 mm.
A 150 mm flat band has a relaxed loop of about 300 mm. Reaching 640 mm means more than doubling that loop length. The listed dimensions alone do not confirm that this is a suitable working stretch.
Starting point: compare the longer No.38, No.69 and No.89 options, then confirm their suitability for your measured route. Do not force a short band around a large box. For repeated packing work, ask us about a suitable larger band if these do not fit comfortably.
An A4 stack 210 mm wide and 20 mm thick needs a loop route of about 460 mm when banded across its width.
No.38 is listed at 152.4 mm flat length, giving an approximate relaxed loop of 304.8 mm. Reaching 460 mm is about 51% extension. That calculation describes the fit required; it is not a manufacturer-approved stretch rating.
Compare No.24 for a narrower strip, No.38 for a medium width, and No.69 or No.89 for wider contact. Trial gently: a band that is too tight may bend the edges.
A roughly round bundle with a 35 mm diameter has a circumference of approximately 110 mm. A No.14 band at 50.8 mm flat length has a relaxed loop of about 101.6 mm, making it a possible starting point for a fit trial.
The number and shape of the pens change the fit. For changing bundle sizes, an assorted pack is often more practical.
A bundle 90 mm across and 20 mm thick has a loop route of approximately 220 mm. No.19, No.33 and No.64 share a listed flat length of 88.9 mm in the Q-Connect range but have different widths.
Their relaxed loop is about 177.8 mm, so the example needs about 24% extension. Compare the widths and trial the grip on your actual contents.
Sending a parcel? An ordinary rubber band is useful for organising or temporarily holding items. It should not replace suitable outer packaging and parcel sealing.
Single sizes, assorted packs and X-bands
Single-size rubber bands
Choose a numbered size when the same job repeats: bundling identical stationery, sorting post or holding similar stock items. Matching length and width makes repeat ordering easier.
A practical starting point for a shared office drawer or jobs that vary. AOS lists assorted packs including 100 g, 454 g and 500 g options, as well as smaller coloured packs. Check the individual listing for the mix supplied.
Use colour to help distinguish small bundles or work in progress. Assorted-colour packs may also contain mixed sizes, so do not assume every colour has the same dimensions.
The Q-Connect X-Band is listed at 100 × 11 mm in assorted colours, in a 100 g pack. It has a different format from a conventional single-loop band: check its product details and fit rather than applying the standard-band chart directly.
A 500 g pack is a weight, not a promise of 500 bands. The number of bands depends on their size, width and material. Compare price per 100 g for similar specifications; where a supplier provides an approximate band count, price per band can also help.
For a regular task, record the brand, size number, dimensions and product code of the band that works. Check the live product page for quantity discounts and availability.
Keep bands in usable condition
Store them away from direct sunlight, heat and sharp edges. Replace bands that become brittle, cracked, sticky or permanently stretched. Avoid pulling a band towards your face or overstretching it to make it fit.
Some products contain natural rubber latex. If latex-free material, direct food contact or another specialist use matters, check the product specification before ordering; an ordinary office band is not automatically suitable.
Rubber band questions answered
Are rubber bands and elastic bands the same thing?
In everyday office use, both names commonly refer to the same type of stretchy loop used for bundling. Material and performance can still vary between products.
Is rubber band size the diameter or the length?
The dimensions on the standard bands in this guide are flat length × band width. Flat length is measured with the band relaxed and flattened; it is not the diameter and not the maximum stretched length.
What is the difference between No.19, No.33 and No.64?
In the Q-Connect listings shown here, all three are 88.9 mm long when laid flat. Their widths are 1.6 mm, 3.2 mm and 6.3 mm respectively. Choose the width as well as the length.
What size rubber band fits a shoebox?
There is no single size for every shoebox. Measure around the width and height, or length and height, depending on the direction of the band. The example in this guide needs a 640 mm loop across the shorter direction. Confirm that a candidate band can handle the required working stretch before using it.
How far can I stretch a rubber band?
There is no reliable universal multiplier for all office rubber bands. Material, thickness, age and product design affect performance. A flat-length measurement does not specify a safe working extension; check manufacturer guidance or trial a suitable sample without forcing it.
Are wider rubber bands always stronger?
Not necessarily. Width affects the contact area, but wall thickness, rubber formulation and stretch also affect holding force and durability. Compare the full specification for a demanding application.
How many rubber bands are in a 500 g pack?
There is no fixed count. Smaller and narrower bands generally give more pieces per pack than larger and wider bands. Only use a quoted approximate count where the individual product listing provides one.
What should I buy if I am unsure of the size?
Measure the item first. An assorted pack can help with varied small office tasks, while a sample or specification check is better for a precise repeat application. Contact AOS with the loop route, item dimensions and intended use if you need help.
Find the right rubber bands for the job
Browse single sizes, assorted packs and specialist formats. For help with repeat orders, tell us the dimensions of your item and how you want the band to hold it.
Measurement reference: Alliance Rubber: how to measure a rubber band. Product dimensions: AOS product listings linked in the chart. Illustrations are explanatory and not to scale. Worked examples are calculated from the stated item dimensions; suitability must be checked for the selected band.
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