What extra Microsoft 365 storage costs, and how to avoid paying for it

When a Microsoft 365 tenant runs out of SharePoint storage, the quick fix Microsoft offers is to buy more. This guide works out what that costs over a year and what the alternatives cost, so you can decide with numbers.

The price of extra storage

Microsoft sells extra SharePoint storage as Office 365 Extra File Storage, at about $0.20 per GB per month at list price, in 1 GB units, billed monthly for as long as you keep it. There is no annual discount worth mentioning and no volume tier for small amounts.

Over the pool by	Per month	Per year
100 GB	$20	$240
500 GB	$100	$1,200
1 TB	$205	$2,460
2 TB	$410	$4,920

The pool itself is 1 TB plus 10 GB per licensed user. Adding users adds 10 GB each; moving everyone to a higher plan does not add SharePoint storage, only OneDrive and mailbox space.

Why the bill grows

Storage use in a tenant only goes one way unless someone acts. Files are added every day; versions accumulate on every edit (SharePoint keeps up to 500 full versions of each file by default); deleted files sit in two recycle bins for 93 days; and copies pile up because it is faster to save a new one than to find the old one. A tenant that is 300 GB over this year is 500 GB over next year, and the monthly charge follows.

The alternatives, with prices

• Empty the recycle bins. Free. Space returns when the second-stage bin is emptied. Everything in it is then permanently gone, so check first.
• Limit versions. Free. Library settings → Versioning, or the tenant-wide automatic version history. New saves respect the limit at once; old versions take effect when they are deleted or the automatic rule reaches them.
• Microsoft 365 Archive. About $0.05 per GB per month for whole sites you keep but do not use, plus a reactivation charge of about $0.60 per GB if you bring a site back. A quarter of the price of active storage, for things you really do not open.
• Remove duplicates and old versions saved under new names. Pay once. A Doppelgone for Work clean-up is $149 for up to 1 TB scanned, $349 up to 5 TB, $799 up to 20 TB. The free audit tells you beforehand how much would come back, so you only pay when the number is worth it. Every removal goes to your own recycle bin, restorable for 93 days.
• Buy more storage. $0.20 per GB per month, forever.

A worked example

A 30-person firm has a 1.3 TB pool and 1.8 TB in use: 500 GB over, $100 a month. The free audit finds 140 GB of exact copies that can go safely and another 90 GB of old versions and near-copies that needs a look. Emptying the bins frees 60 GB more. After a $149 clean-up and an afternoon of review, the tenant is 210 GB over instead of 500: the monthly bill drops to about $42, saving roughly $700 a year, and the version limit stops it climbing back.

Whether the numbers work for you is what the audit is for. It is free, read-only, and changes nothing in your tenant.

Start the free audit · Pricing · SharePoint storage full: what is using it