Rounding on Invoices

Calculations and Rounding on Invoices

PennyPerfect calculates the pension contributions on a per session basis i.e. a contribution is calulcated per session and these values totalled, rather than totalling the value of all sessions and then calculating the contribution from that total. The two different methods can give slightly different total figures because of rounding as demonstrated below. Rounding differences are more likely when there is a high number of sessions in a month.

The per session method ensures the amount invoiced stays consistent regardless of how the sessions are split across invoices i.e. if there are many sessions on a single invoice or they are split across multiple invoices, the total amount invoiced across all of these invoices remains the same and is guaranteed to match the figure on the pension forms. If the calculation method for the pension contributions is done on a per invoice basis, the total figure across invoices can vary depending on how the sessions are split across the invoices.

The two examples below show how the same sessions can result in a different contribution (£84.10 vs £84.12) depending on whether its calculated per session, or per invoice.

Method A. Contribution calculated per session

Five sessions, the contribution is calculated per session, then all these contributions combined to get the total contribution.
Date  Rate  Pensionable  Contribution (14.38%)
12 May£130.00£117.00£16.82
13 May£130.00£117.00£16.82
14 May£130.00£117.00£16.82
15 May£130.00£117.00£16.82
16 May£130.00£117.00£16.82
Total Contribution£84.10

Method B. Contribution calculated per invoice

Five sessions, the contribution is calculated after all the sessions have been totalled.
12 May£130.00 
13 May£130.00 
14 May£130.00 
15 May£130.00 
16 May£130.00 
Total Sessions £650.00
Pensionable (90% of Sessions) £585.00
Contribution (Pensionable * 14.38%) £84.12

Pension legislation is complex and subject to change. PennyPerfect make no claim the information represented here is correct, or that the pension calculations within the PennyPerfect software are correct.