Landlord guide · Spreadsheet or Prism

A spreadsheet or Prism for your lease expiries: what each one does.

Use a spreadsheet if you have a few leases, you have already read each one closely, and you will keep the sheet up to date: it is free, it holds any column you like, and it does not need the lease uploaded anywhere. Use Prism if the dates are still sitting in PDFs you have not read closely, if the notice windows have to be worked out from the clause, or if you want a reminder to arrive without building one. Some landlords will want both: Prism to read the leases and show the clause behind each date, and a spreadsheet for what Prism does not hold, such as rent, arrears and tenant contacts.

Side by side

The job	A spreadsheet	Prism
Where the dates come from	You read each lease and type the dates in.	Prism reads the lease and returns the dates with the sentence each one came from.
Notice windows	You work them out yourself, by hand or with a formula.	Worked out in code from the rule the lease states.
Checking a date	Only if you kept a column for the clause or the page.	The sentence is shown beside every date.
Reminders	Only what you set up: calendar entries or alerts.	For a paid lease, an email 90, 30 and 7 days before each dated deadline, to the address on the account.
Amendments	You edit the row when you remember to.	An amendment is read together with the lease, so its dates replace the lease’s in your list and reminders.
Your own columns	Anything: rent, unit, tenant, contacts, arrears.	None. Prism lists contracts by file name and has no property, unit or tenant fields.
Sorting and reporting	Sort, filter, pivot and chart as you like.	One calendar and one deadline list, soonest first. You can download the dates on your paid contracts as a calendar (.ics) file. There is no spreadsheet download.
Where it can be wrong	A typo, a date read from the wrong page, or a formula that counts months as 30 days.	A date it misses or reads wrong. Its measured results, on synthetic contracts, are on the accuracy page.
What it costs	Nothing, or what you already pay for the software.	$1 per contract, or $9 a month for up to 50. You see a preview of a lease before you pay.
What you hand over	Only what you type. The lease stays where it is.	The lease itself, as a PDF or a photo.

Worked example: one notice date, two ways

One lease ends on Mar 31, 2031, and the tenant must give notice at least nine months before. A spreadsheet gets the notice date right only if its formula counts months on the calendar.

The lease“The Expiration Date is March 31, 2031. Tenant shall give notice of renewal not later than nine (9) months before the Expiration Date.”

Method	Result	Is it right?
Nine months before, counted on the calendar (EDATE in Excel and Google Sheets subtracts months this way)	Jun 30, 2030	Right. June has no 31st, so the last day of June
Nine months taken as 270 days (=B2-270)	Jul 4, 2030	Wrong: four days after the true last day

From Jun 30, 2030 to Mar 31, 2031 is 274 days. Counting 270 days back from Mar 31, 2031 therefore lands four days later than the notice date.

Prism counts months on the calendar too, and where the month is shorter it uses that month's last day. A lease can define the count differently, which is why the clause is shown beside the date.

The lease and its clauses were written for this page, not taken from a customer’s lease. The dates are worked out by hand and checked against the same date arithmetic Prism uses.

Which one to use

A spreadsheet is enough when
You have a few leases, you have read each one closely, the dates are already in the sheet, and you are happy to build your own reminders.
Prism is worth it when
The leases are PDFs you have not read closely, the notice windows have to be worked out, or you want the clause beside every date and an email before each one.
Use both when
You want the dates read for you and also a place for rent, arrears and tenant contacts. Read each lease in Prism and copy the dates you want into your sheet.
Neither replaces reading the lease
Prism shows the sentence so you can check a date in a minute, and a spreadsheet is only as good as the reading behind it. For a lease that matters, read the clause and ask a lawyer.

What it will not do

Prism does not replace a spreadsheet's own columns, does not import a spreadsheet, has no spreadsheet download, and does not track rent, arrears or tenant details. It returns what a lease states and quotes where, misses some dates, and is not legal advice. Reminders are best-effort.

Use it from an AI agent

Prism is a remote MCP server. In Claude Code:

claude mcp add --transport http prism https://prism.parad1gm.com/api/prism-mcp

Then ask: “Read these leases and list every deadline across all of them, soonest first, with the clause each one comes from.” The agent sends the document with prism_review_contract and reads the result with prism_get_contract. Setup for Claude on the web, Cursor, VS Code and A2A agents is on the agents page.

$0.50 a contract for an agent, and the first 3 are free. On the website it is $1 per contract, or $9 a month for up to 50.

Questions

Can I import my spreadsheet into Prism?

No. Prism reads the contracts themselves, as PDFs or photos, and it does not import a spreadsheet. It has no spreadsheet download either, so the way across is to read each lease in Prism and copy the dates you want into your sheet. It can download the dates on your paid contracts as a calendar (.ics) file.

Can Prism check my spreadsheet against the leases?

Not in one step. Read each lease in Prism and compare each date with your row. A date that differs is worth opening the clause for, and the sentence Prism shows next to it is where to look.

Which is more accurate?

Neither is always right. A spreadsheet is as accurate as the person reading and typing, and as the formulas in it. Prism misses some dates and can read a clause wrongly; its measured results, on synthetic contracts, are on the accuracy page, and a period the lease never states is left empty rather than guessed. Prism shows the sentence behind every date, which is what lets you check it quickly. A spreadsheet can do the same if you add a column for the clause.

What does Prism cost against a free spreadsheet?

On the website it is $1 per contract, or $9 a month for up to 50, and you see a preview of a lease before you pay. Loading more than 9 leases in a single month costs less on the monthly plan. A spreadsheet costs nothing to buy; its cost is the time it takes to read each lease and type the dates in.

Where do the reminders go?

To the email address on the Prism account. If several people need them, a calendar or a spreadsheet the whole team uses may suit you better, or both.

Can I ask an AI assistant to keep the list?

Prism is a tool an assistant can call: it sends each lease and reads back the deadlines, and one call lists the open deadlines across every lease in the account. The list lives in your Prism account, not in the chat.

Is this legal advice?

No. It compares two ways of tracking what a lease says. For a decision that matters, read the clause and ask a lawyer.

More for landlords

Every guide here starts from the lease. Prism for landlords shows the whole picture: leases, insurance certificates and loan documents read once and put on one calendar that emails you before each date.

This guide is about what a lease says and which dates follow from it. It is not legal advice, and it does not cover state or local law. How often Prism finds these dates is on the accuracy page.