Sources and limits

How estimates work

Every figure shows its source. Your actual bill is the best source of truth. Replace any estimate with your own amount.

Sources last reviewed 24 August 2026.

What the labels mean

A quick guide to the status shown beside every figure.

Official source
From the published source named beside the figure.
Estimate
A planning figure, not a quote or bill.
Entered by you
Your amount, used instead of our suggestion.
Not available
No sourced figure is available until you enter or choose how to handle it.
Not included
Left out at your request, named beside the total.
Included in rent
Marked as covered by the advertised rent and counted as £0 in the total.

Where the figures come from

The provider, limitation, and source link stay together so you can check any figure.

Figure

Rent check

What we use

Published ONS rent data for the selected property size and area.

Limitation

A guide to recorded local rents, not a valuation of a particular home.

Figure

Council tax

What we use

Official 2026/27 London borough charges for the band you select.

Limitation

Discounts, exemptions and account adjustments are not applied automatically.

Figure

Water

What we use

Thames Water’s 2026/27 assessed household charge for the bedroom count.

Limitation

Metered homes, other suppliers and drainage rebates may cost differently.

Figure

Broadband

What we use

A temporary UK-wide average from Ofcom while local package data is unavailable.

Limitation

It is not a quote; availability and prices vary by address and provider.

Figure

Commute

What we use

An estimate based on published TfL adult fares and the travel choices entered for each household member.

Limitation

Routes, travel times, rail operators and concessions can change the actual cost.

Putting it together

How your monthly total is built

Rent + council tax + utilities + travel

Estimated monthly cost

We add the costs you chose to include; anything left out is named beside the total. It is an estimated monthly cost, not an affordability score.

Return to the true-cost calculator