Multiplying factor (MF)
Definition. The multiplying factor is the number by which the difference between two meter readings is multiplied to obtain billed units, and it is greater than one wherever current transformers scale the current down before it reaches the meter.
Also called: MF · Meter constant · CT ratio
Where you see it: In the reading block, printed as MF or M.F., usually as a whole number.
Why a factor exists at all
A meter cannot carry hundreds of amperes through its own internals. On larger connections, current transformers reduce the current by a fixed ratio and the meter measures the reduced version, so its register accumulates a proportionally smaller number.
The multiplying factor restores the true figure. A factor of 20 means the register advanced by one for every twenty units genuinely consumed.
Domestic connections
An ordinary single-phase domestic meter is a direct-connected device with a multiplying factor of 1. If a domestic bill shows anything other than 1, that is worth querying immediately.
It is a rare error, but it is a catastrophic one — a factor of 10 applied in error multiplies the bill tenfold and nothing else on the page looks wrong.
After a meter change
Replacement meters can have different current transformer ratios from the units they replace. The factor recorded in the billing system has to be updated at the same time, and this is where the mismatch usually creeps in.
Whenever a meter is changed, check the first bill afterwards against the meter change certificate: initial reading, final reading of the old meter, and the new multiplying factor.
A commercial connection with CTs
- Present register: 8,420
- Previous register: 8,190
- Register difference: 230
- Multiplying factor: 20
- Units billed: 4,600 kWh
The meter never displays 4,600. Reading the register alone and expecting it to match the bill is the usual source of confusion on CT-metered connections.
Frequently asked questions
Where do I find the correct multiplying factor for my connection?
On the meter change certificate issued when the meter was installed, and on the CT nameplate at the metering panel. The sub-divisional office holds the same record in the account file.
Can a wrong multiplying factor be corrected retrospectively?
Yes. Once the correct factor is established, the affected cycles are recomputed and the difference appears as an adjustment — a credit if you were overbilled.
Related terms
- Meter reading — How to read a Pakistani electricity meter correctly, which digits to ignore, and how to check the reading printed on your bill against the device on your wall.
- Units consumed — The one number on your bill that you can actually verify yourself, how it is derived from two readings, and the arithmetic that turns it into rupees.
- Maximum demand indicator — Why commercial and industrial bills charge for a single half hour of the month, how MDI is measured, and the practical ways to bring the recorded peak down.
Go further
Back to the full 44-term glossary, or open your own bill with the reference number lookup.