Define the job before you price anything
Start with the job: sending messages, reading DMARC reports, investigating delivery failures or administering domains. List what your existing mailbox or sending service already includes. Budget for a gap you can name, rather than treating every diagnostic feature as essential. If you are not sure which gaps are real yet, run the free email checks first and see what they already reveal.
For each candidate, record the quotation date, currency, included domains, users, message allowance, report retention, support level and renewal terms. Ask whether limits count sent messages, attempted messages, contacts or something else. Do not compare two allowances with different definitions as though they were equivalent.
Use one repeatable cost formula for every quote
Recurring monthly cost = base subscriptions + user and domain add-ons + usage charges + monthly administration hours × hourly cost.
First-year total = 12 × recurring monthly cost + one-off setup fees + setup hours × hourly cost + other one-off charges.
Use the first formula only for reasonably stable usage. If demand changes seasonally, calculate each month separately and add the twelve results instead. For usage billed in blocks, apply the contract's rounding rule. "Per started thousand" is not the same as a proportional per-message charge.
For an annual subscription, insert its actual annual charge directly into the yearly total instead of multiplying a monthly equivalent and accidentally counting it twice. Keep cash paid to suppliers separate from internal staff-time cost. Both matter, but internal time is not another software invoice. Counting your sending routes accurately first will make the usage estimate far more reliable, so use the sender inventory template before you multiply.
Worked example in GBP: what the annual total looks like
These are invented budgeting inputs, not market prices or provider quotations. Assume steady usage, monthly billing, no discounts, no other fees and an internal labour cost of £30 per hour.
- Base subscription: £18 per month, excluding VAT.
- Additional domain allowance: £12 per month, excluding VAT.
- Chargeable usage above the included allowance: exactly 8,000 messages monthly at £0.80 per 1,000, giving £6.40.
- Administration: 1.5 hours monthly × £30 = £45.
- Initial setup: 3 internal hours × £30 = £90, with no supplier setup fee.
Supplier charges are £18 + £12 + £6.40 = £36.40 per month. Add £45 of staff time for a recurring economic cost of £81.40 per month.
The first-year total is 12 × £81.40 + £90 = £1,066.80 before applicable VAT. That comprises £436.80 in supplier charges, £540 in recurring internal time and £90 in setup time. Spreading setup across the year produces an £88.90 monthly equivalent, not an £88.90 monthly invoice.
Keep VAT, currency and cash timing explicit
The UK standard VAT rate is 20%, but the actual tax treatment depends on the supply and your circumstances. VAT rates For this example only, assume all £436.80 of supplier charges attracts 20% VAT and none of that VAT is recoverable. VAT adds £87.36, making supplier cash payments £524.16 and the first-year economic total £1,154.16. No VAT is added to the internal labour allowance in this model.
Do not automatically apply that assumption to overseas subscriptions or treat every VAT-inclusive amount as a permanent business cost. Confirm the invoice treatment, any reverse-charge obligations and recoverability with your finance adviser. Record whether each figure includes or excludes VAT before adding it to the sheet.
If a supplier quotes in another currency, record the exchange-rate assumption and date, plus any card or conversion fee. Run a less favourable exchange-rate scenario. Annual payment can bring a different price and an earlier cash outflow; check cancellation, minimum term, automatic renewal and promotional expiry separately.
Compare outcomes, not just the totals
Recalculate with higher message volume and more administration time. Identify the point where an allowance or plan changes. Then ask whether the tool reduces a measured task, provides evidence you lack or merely duplicates existing reporting. If the case rests on inbox placement, understand what the DMARC reports can and cannot show before spending.
Keep the completed calculation with the quotation and assumptions. A cheaper total is not evidence of better inbox placement: Google does not guarantee that messages from an email provider will pass its spam filters. Email sender guidelines
No affiliate product or paid recommendation is included. The worked example has been checked against the stated assumptions.
Once you have a budget, see how to choose between free checks, monitoring and specialist help and what free checks can already show.
If a quote includes mailbox warm-up, compare the promised service with what responsible email warm-up can do before adding it to the budget.