What does the same period of use actually cost?
A low monthly price can hide the work of switching, checking results and leaving later. Compare options over the same period before treating a quote as the cost of a decision. Include the current arrangement so that doing nothing has a visible operating cost too.
Start with the work the business needs to complete. An option that cannot meet a necessary capability is not made suitable by a low total. Keep capability, access and ownership questions beside the arithmetic. This worksheet organizes your assumptions; it does not supply prices or predict a return.
Set a common horizon and a cost boundary
Choose one currency or cost unit and a number of months. Use the same scope for every option. If one quote includes support and another does not, separate those differences before comparing totals. Obtain current prices from the responsible provider; do not silently mix currencies or pre-tax and tax-inclusive amounts.
A one-time cost happens once within the comparison. Recurring costs are entered per month. If you have an annual quote, divide it by twelve only when that represents the price you would actually pay; an annual minimum commitment may need to be shown as a one-time or contracted cost instead. State your treatment in the fit notes.
Count transition, ongoing work and exit separately
Setup covers configuration or development needed to begin. Transition covers moving records, training people and running old and new arrangements together. Ongoing costs can include licences, infrastructure, support and other recurring work.
Manual hours are a separate optional assumption: monthly hours multiplied by a valuation you supply. They are not automatically cash savings. If staff review time is already in the support figure, do not count it again. Volume charges belong in their own monthly estimate. An exit cost is included once only if it falls within your chosen horizon.
Enter zero when you know a required cost is zero. Leave it blank when it is unknown. The tool reports a known subtotal and an incomplete comparison until required amounts are supplied. Blank optional manual, volume and exit costs are excluded, and should be investigated when material. A complete arithmetic entry is still only as useful as its assumptions.
| Category | When counted | Question to resolve |
|---|---|---|
| Setup and transition | Once | What must happen before the team can use it? |
| Licence, infrastructure, support, other | Each month | Does the quote cover the same service and usage? |
| Manual work | Monthly hours × your valuation | Is this additional work, already counted, or time released rather than cash saved? |
| Volume charges | Each month at your stated volume | What happens when usage changes? |
| Exit | Once within the horizon | What would exporting data and replacing the arrangement require? |
Fictional example: two booking arrangements
Every amount in this example is invented, in GBP, over twelve months. It is a demonstration of the method, not a price benchmark. The current arrangement has no setup charge, a £200 transition allowance, £50 monthly support and ten manual hours per month valued at £20 each. Other required recurring categories are explicitly zero. Its declared total is 200 + 12 × (50 + 10 × 20) = £3,200.
A subscription option has £500 setup, £200 transition, £80 monthly licence, £50 support and three monthly manual hours at the same valuation. Infrastructure and other recurring costs are zero. Its declared total is 500 + 200 + 12 × (80 + 50 + 3 × 20) = £2,980. Volume and exit costs are excluded from both examples, not established as free.
The £220 difference does not settle the decision. The subscription still needs a capability check, confirmation of booking status and a workable exit. At six months the totals become £1,700 and £1,840 respectively. Changing the horizon can change the comparison without making either option right.
Use the comparison worksheet
The interactive companion below produces an editable draft and calculation breakdown. Without JavaScript, copy this worksheet and calculate each option using the same horizon. Keep unknowns visible.
Currency/unit:
Common horizon in months:
For each option:
Name and capability/fit notes:
One-time setup:
One-time transition:
Monthly licence:
Monthly infrastructure:
Monthly support:
Other monthly cost:
Optional monthly manual hours and hourly valuation:
Optional monthly volume cost:
Optional exit cost within horizon:
Known subtotal = setup + transition + months × (licence + infrastructure + support + other + hours × valuation + volume) + exit
Missing required amounts:
Assumptions and evidence owner:
Next decision and review trigger:Use the result to choose the next question
Ask which uncertain amount or capability could materially change the choice. Request that evidence before buying, building or promising a transition. Revisit the comparison when scope, usage or contract terms change. Cost is one part of judgment, alongside fit, dependencies and operating responsibility.