This page explains the Colorado PERA calculator. The rules it uses are in plain English on the benefit formula, Rule of 80 to 90 and reduced retirement pages.
- 1
Find your HAS table
You pick it, or we use your membership date. Before 2011 we also test whether you could retire on January 1, 2011 (from your age and your service that day, which we estimate from your membership date if you don't enter it). Joined 2017 through 2019: PERA 7 unless you tick that your recent service was outside the School and DPS Divisions.
Your PERA Benefits p. 16, Highest Average Salary Percentages Tables (chart); C.R.S. 24-51-605(3), (4) ("eligible for a reduced service retirement benefit as of January 1, 2011" / "not eligible for a retirement benefit as of January 1, 2011") - 2
Project your service
We add the time from today to your retirement date to the service you enter, a year for each year. The work-longer comparison adds a year of service for each year and keeps your HAS the same.
Our assumption (see below) - 3
Check the retirement rules
Your age (reached by the end of your retirement month) and service against your table's full-benefit rules, including the Rule of 80, 85, 88 or 90, then its reduced-retirement rules.
C.R.S. 24-51-602(1.5), (1.8); Your PERA Benefits p. 6 (lists 58/30 and 60/28); C.R.S. 24-51-604(1), Table C; Your PERA Benefits p. 7 (Membership Started Before January 1, 2020); C.R.S. 24-51-604(2), Table C.1; Your PERA Benefits p. 7 (Membership Started on or After January 1, 2020) - 4
Apply the formula or the table
Full benefit: 2.5% × years of service, up to 100%, × your monthly HAS. Reduced: the percentage in your table's box for your age and whole years, part of the way to the next year's box for a part year.
Your PERA Benefits p. 7, Defined Benefit Calculation; C.R.S. 24-51-603(1)(a); Your PERA Benefits pp. 17-25 (note under each PERA table); Understanding Your Benefit Estimate PDF p. 1 (33.5 years -> 83.75%); Your PERA Benefits p. 7, Defined Benefit Calculation; p. 16; Understanding Your Benefit Estimate PDF p. 1 - 5
Compare with money purchase
If you enter a money purchase amount from a PERA estimate and it's higher, we show it, because PERA pays the higher one.
Your PERA Benefits p. 7, Benefit Calculation, Money Purchase Benefit Calculation; C.R.S. 24-51-605.5 - 6
Add the dates and extras
Earliest and full-benefit dates, the first annual increase (36 months of payments, and for reduced retirees age 60 or the full-benefit total by January 1), the AI at 1% after 2027, and the PERACare subsidy.
Annual Increases fact sheet pp. 1-2, First AI; C.R.S. 24-51-1001(1)(b.5), (3.5); Automatic Adjustment fact sheet p. 1; PERACare Pre-Medicare 2026 pp. 16-17 (maximum $230, Monthly Subsidy Chart); PERACare Medicare 2026 pp. 12-13 (maximum $115, Medicare Benefit Recipient Monthly Subsidy Chart); C.R.S. 24-51-1206(2), (3)
What the calculator doesn't cover
- Your HAS. We use the monthly figure you enter; PERA works it out from your salary records, with the raise cap.
- Options 2 and 3. PERA doesn't publish the reduction factors.
- The money purchase benefit, unless you enter PERA's figure.
- The DPS benefit structure, the State, Local Government and Judicial Divisions, Safety Officers, and the PERA DC Plan.
- Disability retirement, the cost of buying service, the federal Section 415 limit, taxes, PERACare premiums, and what the annual increase will be after the published years.
- The pre-2007 members' lump sum with the first annual increase, and indexing of deferred benefits.
How we check the math
The calculator runs on a small engine that reads every rule from one data file, with a source for each. The HAS tables were read from PERA's booklet, box by box. Automated tests check the engine against PERA's worked examples and every box of the nine tables, plus the edges of each rule (birthdays, January 1, 2011 and 2020, the Rule of N, the 36 months before the first annual increase). The tests run every time the site is built.
| Example | Source shows | Our engine | Source |
|---|---|---|---|
| Part year: 33.5 years | 83.75% | 83.75% | Understanding Your Benefit Estimate PDF p. 1, What happens if I retire between boxes on the PERA HAS table? Match |
| 3-year HAS example (a month) | $2,021 | $2,021 | Your PERA Benefits p. 7, PERA 3-Year HAS Calculation Example Match |
| 5-year HAS example (a month) | $2,079 | $2,079 | Your PERA Benefits p. 8, PERA 5-Year HAS Calculation Example Match |
| Full-benefit boxes = 2.5% × years, PERA 1 to 9 | 1330 boxes | 1330 match | Your PERA Benefits p. 17, PERA 1 Highest Average Salary Percentages for Retirement Benefit Option 1; Your PERA Benefits p. 18, PERA 2 Highest Average Salary Percentages for Retirement Benefit Option 1; Your PERA Benefits p. 19, PERA 3 Highest Average Salary Percentages for Retirement Benefit Option 1; Your PERA Benefits p. 20, PERA 4 Highest Average Salary Percentages for Retirement Benefit Option 1; Your PERA Benefits p. 21, PERA 5 Highest Average Salary Percentages for Retirement Benefit Option 1; Your PERA Benefits p. 22, PERA 6 Highest Average Salary Percentages for Retirement Benefit Option 1; Your PERA Benefits p. 23, PERA 7 Highest Average Salary Percentages for Retirement Benefit Option 1; Your PERA Benefits p. 24, PERA 8 Highest Average Salary Percentages for Retirement Benefit Option 1; Your PERA Benefits p. 25, PERA 9 Highest Average Salary Percentages for Retirement Benefit Option 1 Match |
| PERA 9, 30 years: age 55 / age 64 | 49% / 75% | 49% / 75% | Your PERA Benefits p. 25, PERA 9 table Match |
| Working after retirement: 60 days + 90 hours | 74 days | 74 days | Working After Retirement p. 1, Workday Limit Definition, Example Match |
| PERACare subsidy, 1 year (before / with Medicare) | $11.50 / $5.75 | $11.50 / $5.75 | PERACare Pre-Medicare 2026 pp. 16-17 (maximum $230, Monthly Subsidy Chart); PERACare Medicare 2026 pp. 12-13 (maximum $115, Medicare Benefit Recipient Monthly Subsidy Chart); C.R.S. 24-51-1206(2), (3) Match |
| PERACare subsidy, 10 years (before / with Medicare) | $115.00 / $57.50 | $115.00 / $57.50 | PERACare Pre-Medicare 2026 pp. 16-17 (maximum $230, Monthly Subsidy Chart); PERACare Medicare 2026 pp. 12-13 (maximum $115, Medicare Benefit Recipient Monthly Subsidy Chart); C.R.S. 24-51-1206(2), (3) Match |
| PERACare subsidy, 20 years (before / with Medicare) | $230.00 / $115.00 | $230.00 / $115.00 | PERACare Pre-Medicare 2026 pp. 16-17 (maximum $230, Monthly Subsidy Chart); PERACare Medicare 2026 pp. 12-13 (maximum $115, Medicare Benefit Recipient Monthly Subsidy Chart); C.R.S. 24-51-1206(2), (3) Match |
| First AI after a July 1, 2026 retirement | three Julys later | July 1, 2029 | Annual Increases fact sheet pp. 1-2, First AI; C.R.S. 24-51-1001(1)(b.5), (3.5) Match |
PERA rounds its HAS examples to whole dollars; our engine's $2,020.83 and $2,078.63 round to the same. PERA's working-after-retirement example rounds 73.75 days to 74.
Things to check with PERA
The sources don't settle these points. Each is labeled "Check with PERA" where it shows up on the site.
When you take a reduced (early) benefit with a part year of service, PERA's tables only show whole years. PERA's fact sheet shows a part-year example only for a full benefit (33.5 years = 83.75%).
What we use: We go part of the way between the two whole-year boxes at your age, in proportion to the part year.
What would settle it: A PERA benefit estimate for a reduced retirement with fractional service and age, or PERA's calculation rules.
Understanding Your Benefit Estimate PDF p. 1PERA's sources don't say exactly how a birthday that falls in your retirement month counts.
What we use: We count the age you reach by the last day of your retirement month, both for eligibility and for the column of the table.
What would settle it: PERA Rules on effective dates, or a PERA estimate for a member whose birthday falls in the retirement month.
Retirement Process p. 4, Effective Date of RetirementIf you joined before 2011, your table (PERA 1 or 2, 3 or 4, 5 or 6) depends on whether you could already retire on January 1, 2011. That depends on your age and service on that day.
What we use: We test your age and service on January 1, 2011. If you don't enter that service, we estimate it from your membership date as if you worked without a break. Your PERA account shows your actual table.
What would settle it: The member's PERA account (it shows which HAS table applies).
Your PERA Benefits p. 16; C.R.S. 24-51-605(3), (4)PERA limits how much each year's pay can rise in the HAS (8% or 15%). It doesn't say whether the limit is measured from the year before as paid or as already limited.
What we use: We measure from the year before as already limited. PERA's own examples stay under the limit, so they come out the same either way.
What would settle it: PERA Rule on HAS or a worked example where a raise exceeds the cap.
Your PERA Benefits p. 7PERA doesn't spell out how it counts the 36 months of payments before your first annual increase.
What we use: We count 36 monthly payments from your retirement date to July 1. A July 1 retirement gets its first increase three years later.
What would settle it: PERA AI eligibility worksheet or a retiree's first AI notice.
Annual Increases fact sheet pp. 1-2, First AIIf you joined in 2020 or later and take a reduced benefit, PERA's fact sheet says your first annual increase waits until you reach age 60 (or the age-plus-service total for a full benefit). State law says age 64 (or a total of 94).
What we use: We follow PERA's fact sheet (age 60) and mark it here.
What would settle it: PERA confirmation of which applies.
Annual Increases fact sheet p. 2; C.R.S. 24-51-1001(3.5)(b)(VI)The copy of state law we use includes changes made through 2025. Laws passed in 2026 may have changed some rules.
What we use: We use PERA's 2026 booklets first, and the 2025 law where the booklets are silent.
What would settle it: Colorado PERA Law 2026 edition or the 2026 C.R.S.
Colorado PERA Law 2025 (title page)If you joined in 2017 through 2019, you're on PERA 7 if your most recent 10 years of service are in the School or DPS Divisions, and PERA 8 if not.
What we use: We assume PERA 7 because this site is for school employees. Pick PERA 8 in the calculator if your recent service was in another division.
What would settle it: The member's PERA account.
Your PERA Benefits p. 16PERA pays the higher of the formula benefit and a money purchase benefit. The money purchase benefit depends on your account balance and PERA's factors, which aren't published.
What we use: We can't work it out. If your PERA estimate shows a money purchase amount, enter it and we use whichever is higher.
What would settle it: A PERA benefit estimate.
Your PERA Benefits p. 7, Money Purchase Benefit CalculationState law adds your age and your years of service, but doesn't say whether part years of age count.
What we use: We use your age in years and months plus your exact service.
What would settle it: PERA Rules or an estimate for a member who meets the Rule of N mid-year.
C.R.S. 24-51-602Colorado's pension exclusion covers survivor benefits at any age, but PERA's tax booklet gives amounts only for ages 55 and up.
What we use: We show $20,000 for a survivor under 55.
What would settle it: Colorado Department of Revenue, Income Tax Topics: Social Security, Pensions, and Annuities.
Taxes on PERA Benefits p. 3, Colorado State Income TaxPERA's list of who can choose the PERA Defined Contribution (DC) Plan doesn't include school district employees, but the sources don't say so in words.
What we use: We say school employees aren't on the list, and we don't model the DC Plan.
What would settle it: PERAChoice booklet or PERA confirmation.
DC Plan overview p. 1, PERAChoiceWhere the sources differ
- Your PERA Benefits p. 6 lists only fixed age/service pairs for service retirement (e.g. 2011-2016 members: 35/any, 58/30, 60/28, 65/any). The statute adds age-plus-service rules (Rule of 80 at 55+, 85 at 55+, 88 at 58+, 90 at 60+, 94 at 64+). The booklet's own HAS tables (pp. 17-25) show unshaded full-benefit cells exactly where the statute's rules put them (checked for every cell of PERA 1-9; e.g. PERA 7 has 72.5% unshaded at age 59 with 29 years). The engine follows the statute and the tables; this is a gap in the chart, not a true conflict. Your PERA Benefits p. 6 and pp. 17-25; C.R.S. 24-51-602
- The AI fact sheet says reduced retirees must reach 'age 60 or the age and service combination for an unreduced benefit' by Jan. 1 of the AI year. The statute sets age 64 / Rule of 94 for members who began on or after Jan. 1, 2020. Following the fact sheet (age 60) per the brief, recorded here and in needsValidation. Annual Increases fact sheet p. 2; C.R.S. 24-51-1001(3.5)(b)(VI)
- Statute sets the AI at 1.5% (pre-2007 members) 'unless adjusted pursuant to section 24-51-413'; PERA's fact sheets give 1.0% for 2026 and 2027 after automatic adjustments. The engine uses the fact sheet's current rate as the default projection. Annual Increases fact sheet p. 1; Automatic Adjustment fact sheet p. 1; C.R.S. 24-51-1002(2)
- For reduced retirees who began July 1, 2005-Dec. 31, 2006 the statute's AI test is age-plus-service 85 (24-51-1001(1)(b.5)(II)) even though their full-benefit rule is 80. The fact sheet just says 'the age and service combination for an unreduced benefit'. The engine uses the statute's 85. C.R.S. 24-51-1001(1)(b.5)(II); Annual Increases fact sheet p. 2
One reading note: the PDF text for the PERA 2 table, 16 years, comes out in the wrong order; the printed page gives 33.5% at age 60, and that's what we use.
Sources
- Your PERA Benefits: A Summary of the Colorado PERA Defined Benefit Plan, Revised April 2026
- PERA 1-9 Highest Average Salary Percentages tables (standalone PDFs), PERA 1, 3, 5 effective Jan. 1, 2011; PERA 2, 4, 6-9 effective Mar. 1, 2025
- Retirement Process, Revised September 2026
- PERA Benefit Structure: Understanding Your Benefit Estimate (8/85, rev. 2-25), 8/85 (REV 2-25)
- Annual Increases for Benefit Recipients, 2/247 (REV 7-26), July 2026
- Automatic Adjustment Provision, 05/174 (REV 6-26), June 2026
- Working After Retirement, Revised July 2026
- Taxes on PERA Benefits, Revised January 2026
- PERACare Health Benefits Program 2026 booklets (Pre-Medicare; Medicare), 2026 plan year
- PERA Overview for Defined Contribution Plan Members (rev. Oct. 2026), Revised October 2026
- Other PERA booklets and fact sheets (Survivor Benefits, Purchasing Service Credit, PERA Overview for New Members, Contribution Rates, School and DPS Divisions Service Credit, PERAChoice booklet, Changing Your Cobeneficiary, Disability Program, FAQ for Retirees, Working During the Effective Month, Working After Retirement for a Colorado PERA Employer), retrieved 2026-11-11 (each file's revision date is on its cover)
- Colorado PERA Law (reprint of C.R.S. Title 24, Article 51), Includes Legislation Enacted in 2025
Spot an error? Tell us. PERA's number is 800-759-7372.
Source: Your PERA Benefits: A Summary of the Colorado PERA Defined Benefit Plan, Revised April 2026, pp. 6, 7, 8, 16, 17, 17-25, 18, 19, 20, 21, 22, 23, 24, 25. Also: C.R.S. 24-51-602, 24-51-603, 24-51-604, 24-51-605, 24-51-605.5, 24-51-1001, 24-51-1002, 24-51-1206; Understanding Your Benefit Estimate; Annual Increases fact sheet pp. 1, 1-2, 2; Automatic Adjustment fact sheet p. 1; PERACare Pre-Medicare 2026 pp. 16-17; PERACare Medicare 2026 pp. 12-13; Retirement Process p. 4; Colorado PERA Law 2025; Taxes on PERA Benefits p. 3; DC Plan overview p. 1; Working After Retirement p. 1. Last reviewed .