Colorado has no statute requiring landlords to prorate rent for a partial month of occupancy. What Colorado does have is one of the more actively evolving landlord-tenant frameworks in the country — Colorado Revised Statutes Title 38, Article 12 — and a fresh round of security deposit protections (HB25-1249) that took effect January 1, 2026 and give renters new tools when a dispute involves money owed.

Is Prorated Rent Required in Colorado?

No. Colorado law does not address prorated rent directly. Like most states, whether your first or last month is prorated comes down to your lease language and standard industry practice, not a statute. Colorado courts generally enforce the lease as written, so if your lease is silent on proration, you'll be negotiating from the norm rather than a legal mandate.

In practice, professional landlords and property managers across Denver, Colorado Springs, and Boulder prorate as a matter of course — it's expected, and refusing to do so on a mid-month move-in is unusual enough to raise questions.

How Prorated Rent Is Typically Calculated in Colorado

Colorado landlords commonly use the calendar-days method, though the 30-day method also appears in leases.

Example: Monthly rent $1,800, move-in date in Denver on the 11th (30-day month).

  • Days occupied: the 11th–30th = 20 days
  • Calendar days: $1,800 ÷ 30 × 20 = $1,200.00
  • 30-day method: same result this month since the month has 30 days
  • Annual method: ($1,800 × 12 ÷ 365) × 20 = $1,183.56

Run your own numbers with our free prorated rent calculator.

Colorado Security Deposit Rules (Updated for 2026)

Colorado Revised Statutes § 38-12-103 governs security deposits, and House Bill 25-1249 added meaningful new protections effective January 1, 2026:

  • Maximum deposit: No statutory limit
  • Return deadline: 30 days after lease termination or surrender of the unit, unless the lease specifies a longer period — capped at 60 days maximum
  • Interest: Not required under Colorado law
  • Documentation on request: As of 2026, if a tenant requests supporting documentation for deductions in writing, the landlord must provide it within 14 days
  • Pre-existing damage: Landlords may not deduct for damage or defects that existed before the tenancy began
  • Unreasonable retention presumption: If a landlord withholds 125% or more of the amount actual damages justify, the retention is presumed unreasonable
  • Penalty for non-compliance: A landlord who misses the deadline or fails to give the required written statement waives the right to retain any portion of the deposit

That waiver provision is significant — it means a landlord who simply misses the 30-day (or lease-specified) deadline can lose the right to keep any of the deposit, regardless of whether damage actually occurred. If your Colorado landlord is slow to respond about your deposit, the calendar itself is on your side.

Notice Requirements for Month-to-Month Tenancies

Colorado scales notice requirements to how long you've lived at the property:

  • 1 year or more: 91 days written notice
  • 6 months to 1 year: 28 days written notice
  • 1 to 6 months: 7 days written notice
  • 1 week to 1 month: 3 days written notice
  • Less than 1 week: 1 day notice

This sliding scale cuts both ways — it applies whether the landlord or the tenant is ending the tenancy.

Colorado Small Claims Court

  • Claim limit: $7,500, exclusive of interest and court costs
  • Where filed: Small Claims Division of the County Court
  • Attorneys: Generally not used in small claims — the process is designed for self-represented parties

$7,500 comfortably covers the vast majority of prorated rent and security deposit disputes, even in Colorado's higher-rent markets.

Colorado Tenant Resources

  • Colorado Division of Housing: doh.colorado.gov — state landlord-tenant guidance and lease termination info
  • Colorado Judicial Branch Legal Help Center: lawhelp.colorado.gov — plain-language guides on deposits and small claims
  • Colorado Legal Services: Free legal help for qualifying tenants statewide
  • Statute reference: C.R.S. Title 38, Article 12 (as amended by HB25-1249, effective Jan. 1, 2026)

What to Do If You've Been Overcharged in Colorado

  1. Calculate the correct prorated rent using our calculator
  2. Check your lease for proration language or an implied per-day rate
  3. Put your calculation in writing and send it to your landlord
  4. If it involves your deposit, request supporting documentation in writing — Colorado now requires a response within 14 days
  5. Send a formal rent dispute letter if informal contact doesn't resolve it
  6. File in Colorado small claims court for amounts up to $7,500

The Bottom Line

Colorado doesn't mandate prorated rent, but its 2026 security deposit overhaul gives tenants sharper tools than most states offer: a hard 14-day documentation deadline, a ban on charging for pre-existing damage, and a waiver penalty for landlords who blow the return deadline. Keep your calculations and requests in writing, and use the new rules as leverage if a Colorado landlord is slow to account for your money.