IT ONLY TAKES A MINUTE!
Franking Machine Scales: 5 Weighing Options Compared (2026)
Get the weight wrong and you either overpay for postage or your mail comes back with a surcharge. That's why the scale is one of the most important parts of a franking machine, and one of the most overlooked when people compare models.
This guide explains the five main weighing options, the scale limits on popular machines and how to pick the right setup for what you post.
Why weight matters so much
Royal Mail prices letters and large letters in weight bands. Cross a band and the price jumps. From 7 April 2026, a 1st Class large letter franked costs:
| Weight up to | 1st Class franked | 2nd Class franked |
|---|---|---|
| 100g | £2.86 | £1.52 |
| 250g | £3.28 | £1.81 |
| 500g | £3.30 | £2.30 |
| 750g | £3.30 | £2.50 |
Source: Royal Mail Business Price Guide, prices from 7 April 2026.
A 2nd Class large letter at 251g costs 49p more than one at 250g. Weigh accurately and you pay for what you send, no more.
The 5 weighing options
1. Built in scale
Most small and mid sized machines have a scale built into the top. You place the item on it, the machine reads the weight and sets the postage. Limits vary a lot:
| Machine | Built in scale |
|---|---|
| FP PostBase Vision 3S | 2kg |
| FP PostBase Vision 5S | 5kg |
| Pitney Bowes SendPro C | 5kg |
| FP PostBase Vision 7A | 7kg |
| FP PostBase Vision 9A | 10kg |
Specs from manufacturer and dealer spec sheets, checked October 2026.
Good for most offices posting letters and small packets.
2. External weighing platform
A separate platform connected to the machine for heavier items. The Quadient iX-3, iX-5 and iX-7, for example, can take platforms up to 35kg. If you post parcels regularly, a platform saves you weighing them on kitchen scales and typing the weight in.
3. Manual weight entry
Every machine lets you key in a weight. That's fine for the odd item, but it's slow and it's easy to make mistakes. Don't rely on it if you post parcels every day.
4. Differential weighing
You put a stack of mixed items on the scale. As you lift each one off, the machine measures the drop in weight and sets the postage for that item. The FP PostBase Vision 7A offers this, and it's a real time saver for offices posting lots of different sizes.
5. Dynamic weighing
Found on mailroom machines. Items are weighed as they move through the machine, so mixed batches can be franked without stopping. The FP Vision 9A and Quadient iX-7 both offer dynamic weighing, with the iX-7 quoted at about 110 items a minute when weighing dynamically.
Which option do you need?
| Your post | Weighing option |
|---|---|
| Mostly standard letters | Built in scale (2kg is plenty) |
| Letters and some small packets | Built in scale of 5kg or more |
| Regular parcels | Built in scale plus external platform |
| Lots of mixed sizes every day | Differential weighing |
| Hundreds of mixed items in batches | Dynamic weighing |
Calibration and accuracy
Franking machine scales are approved for trade use, but they still need to be looked after. Keep the scale clean and level, don't drop heavy parcels on it and check it occasionally against a known weight. If readings start to drift, call your supplier. Most leases include servicing.
Size matters too
Weight isn't the only thing that sets the price. Royal Mail also checks size. A large letter can be up to 353mm by 250mm and 25mm thick, and up to 750g. Anything bigger is a parcel. Many small machines can only feed items up to 5mm to 10mm thick, so thicker items need a label. See our guide to franking large letters and parcels.
Common weighing mistakes
- Weighing before sealing. Add the last insert, seal, then weigh.
- Leaving items on the scale. A pen left on the platform adds weight to every item.
- Ignoring the band edges. If an item sits right on 100g, one more sheet tips it over. Trim inserts where you can.
- Using the wrong class. Check the class before you frank, because changing it afterwards isn't always simple.
Scale checklist before you sign
Before you agree a lease, ask the supplier these questions about weighing:
- What is the built in scale limit, and what platforms can be added later?
- Is differential or dynamic weighing an option on this model, and at what extra cost?
- How is the scale calibrated, and is recalibration included in servicing?
- Can the machine read weight from a platform automatically, or must staff type it in?
- What is the thickness limit for items fed through the machine?
Write the answers into the quote. If you later find the scale too small, upgrading mid lease can be expensive, so it pays to get it right at the start.
FAQs
Can I use my own scales with a franking machine?
You can weigh items separately and type the weight in, but connected scales are faster and less error prone.
What happens if I underpay?
Royal Mail may charge a surcharge or return the item. Weighing accurately avoids both.
Do I need differential weighing?
Only if you post a lot of mixed items. For mostly similar letters, a standard scale is fine.
Compare machines with the right scale
Tell us what you post and we'll connect you with approved suppliers who can match the scale to your needs. See our franking machine sizes guide or compare franking machine prices.
