CSRS Annuity Calculator

Estimate your Civil Service Retirement System basic annuity using the official OPM tiered formula, see the exact monthly cost of each survivor benefit election, and compare your CSRS benefit to what FERS would pay for the same service history. Enter your numbers — results appear instantly.

How CSRS survivor benefit cost is calculated

Unlike FERS's simple flat 5% or 10% reduction, CSRS uses a tiered cost formula tied to a fixed $3,600 threshold:²

• 2.5% of the first $3,600 of your designated survivor base, plus
• 10% of the amount above $3,600, up to your chosen designated base.

Your spouse then receives 55% of the designated base after your death — COLA-indexed annually under CSRS. The designated base can be your full annuity or any partial amount (with your spouse's notarized consent for less than the maximum).

What each input means

High-3 average salary

The highest average basic pay over any three consecutive years — almost always your final three years. CSRS uses basic pay only: excludes locality pay above the GS base table, overtime, awards, and bonuses. If you had a promotion in the last three years, your high-3 may be lower than your current salary. Check your most recent SF-50 for your base pay rate.

Years of creditable service

Total years including periods of part-time service (credited proportionally), military service you've bought back, and any unused sick leave (see below). Periods of Leave Without Pay (LWOP) beyond 6 months per year generally do not count.

Unused sick leave

OPM credits unused sick leave toward your total service for annuity calculation purposes. This has applied to CSRS for decades (FERS adopted it later). Each full 2,087 hours equals one additional year of service. Enter months for convenience — this calculator converts to fractional years and applies the 2% tier rate (since sick leave applies after career years).

Survivor benefit election

CSRS allows any designated base from $0 to your full annuity. The calculator models the three common choices: none (life-only), half-base (survivor receives 55% of half your annuity), and full-base (survivor receives 55% of full annuity). Elections less than the maximum require your spouse's notarized consent and are essentially irrevocable once annuity payments begin.

The 80% cap: when more service stops helping

CSRS annuities are capped at 80% of your high-3 average salary. The math: years 1–5 contribute 7.5%, years 6–10 add 8.75%, and the 2% tier from year 11 onward adds 2% per year. Reaching 80% requires:

7.5% + 8.75% + (n × 2%) = 80% → n = 31.875 → total service ≈ 41 years 10.5 months

Most federal employees retire before hitting the cap. But if you're approaching 42 years of federal service, additional years do not increase your basic annuity. They may still be valuable for FEHB premium-free retirement eligibility, CSRS Offset SS coordination, or other reasons — but the annuity formula itself is maxed.

CSRS vs FERS: the generosity gap in real numbers

The comparison table above shows the gap for your specific inputs. The underlying math: CSRS's tiered formula accelerates to 2% per year after 10 years and never resets, while FERS pays a flat 1.0% (or 1.1% at age 62+ with 20+ years). A 32-year employee:

• CSRS: 7.5% + 8.75% + 44% = 60.25% of high-3
• FERS (1.0%): 32 × 1.0% = 32% of high-3
• FERS (1.1%): 32 × 1.1% = 35.2% of high-3

CSRS is roughly 1.9× more generous at 32 years. At 40 years, the gap widens further. This generosity is why CSRS was closed to new hires in 1984 — the government shifted to FERS's less expensive formula for all post-1983 employees.

CSRS employees approaching retirement sometimes underestimate how valuable this benefit is compared to what they could replicate with an IRA rollover or commercial annuity. A fee-only specialist can run the actuarial present-value calculation and put a dollar figure on the lifetime value of your annuity.

COLA: CSRS's full inflation protection

CSRS retirees receive the full CPI-W cost-of-living adjustment each January. FERS retirees receive a "diet COLA" capped at 2.0% when CPI is between 2% and 3%, and 1 percentage point below CPI when it exceeds 3%.³

For 2026, CSRS retirees received a 2.8% COLA (full CPI-W), while FERS retirees received 2.0%. Over a 25-year retirement, the compounding gap is material: a $4,500/month CSRS annuity at 2.8% annually reaches roughly $9,000/month by year 25, versus about $7,400/month under the FERS diet formula — a difference of over $19,000/year.