Methodology & sources
Every rate table, window, formula, and limit of the peak-surcharge calculator, in the open. Found an error? support@whetstonetools.com.
Last updated June 12, 2026 · 2025-26 season schedules (most recent published), last verified June 10, 2026
1 · Scope
The tool computes the cost of published all-shipper peak/demand surcharges — the temporary per-package and per-incident fees UPS, FedEx, and USPS add during the holiday season — for a shipper's weekly volume, ship-date range, service tier, and residential mix. It compares the three carriers per package per week and names the cheapest. It does not model base rates, fuel surcharges, DAS/EDAS, year-round residential or handling fees, DIM weight, or negotiated discounts: the output is the peak-surcharge delta only.
2 · Formulas
Dates are inclusive; rate resolution is per day; weeks are Sunday–Saturday.
rate(component, date) = rates[window containing date], else 0
daily_vol = weekly_volume / 7 (simple model; no ship-days-per-week input in v1)
perPkg(carrier, d) = demandRate(carrier, service_tier, d) × resMult(carrier, service_tier)
+ pct_addl_handling/100 × ahsRate(carrier, d)
+ pct_large_pkg/100 × largePackageRate(carrier, d)
+ pct_over_max/100 × overMaxRate(carrier, d)
resMult = pct_residential/100 if the component is residential-only, else 1 — UPS Ground and
FedEx Ground/Home Delivery demand surcharges are residential-only; UPS Ground Saver, FedEx Ground Economy,
and all USPS services are inherently residential-priced (multiplier 1); UPS Air and FedEx Express demand
applies regardless of residential per the embedded flag (see the UPS confidence note below).
USPS: perPkg(usps, d) = matrix[service|category|zone|weight] if d in window, else 0 — USPS
has no peak handling fees (year-round nonstandard fees are out of scope), so the handling terms are 0.
Over-maximum maps to FedEx's "Ground Unauthorized Package" charge.
weekPerPkg(c, w) = average of perPkg(c, d) over ship days d in week w — per-day averaging
handles weeks that straddle a window boundary automatically (e.g., the week of Oct 26, when UPS's demand
window has started but FedEx's hasn't).
weekTotal(c, w) = weekPerPkg × weekly_volume × (ship days in w) / 7
seasonTotal(c) = Σ over weeks of weekTotal(c, w)
Enterprise mode (optional, off by default, only for shippers billing >20,000 packages/week):
UPS: demandRate ← tierRate(peaking_factor, window kind) — the tier rate replaces the
base demand rate. FedEx: demandRate += residentialDeliveryTier(peaking_factor) for residential
packages, Oct 27 – Jan 18 — the tier charge is added on top of the published demand surcharge.
Enterprise outputs are labeled "estimate — UPS locks tiers season-long once qualified; FedEx re-rates
weekly."
3 · UPS 2025-26 confidence: cross-verified secondary
Confidence: SECONDARY (cross-verified). The official UPS schedule PDF on assets.ups.com timed out from the build network, so every cell below was cross-verified across 4 agreeing secondary sources (Supply Chain Dive, DCL, 3PL Center, Sifted, with goshippo for the handling fees). The official PDF ("August 28, 2025 Update") is cited below for re-verification on refresh.
| Window | Dates |
|---|---|
| W1 | Sep 28 – Oct 25, 2025 (handling-type fees only) |
| W2 | Oct 26 – Nov 22, 2025 |
| W3 (peak) | Nov 23 – Dec 27, 2025 |
| W4 | Dec 28, 2025 – Jan 17, 2026 |
| Component | Applies to | Residential only | W1 | W2 | W3 | W4 |
|---|---|---|---|---|---|---|
| Demand — Ground Residential | ground | yes | $0 | $0.40 | $0.60 | $0.40 |
| Demand — Ground Saver (fka SurePost) | economy | no (inherently residential) | $0 | $0.40 | $0.60 | $0.40 |
| Demand — Air (all air services)* | express | no* | $0 | $1.10 | $2.05 | $1.10 |
| Demand — Additional Handling | all | no | $8.25 | $8.25 | $10.80 | $8.25 |
| Demand — Large Package | all | no | $90.50 | $90.50 | $107.00 | $90.50 |
| Demand — Over Maximum Limits | all | no | $485 | $485 | $540 | $485 |
*Open verification item (flagged in the data as confidence: secondary): whether UPS's all-shipper air demand surcharge applies to commercial air for sub-20k shippers, or residential air only. Sifted's enterprise table charges Air Commercial the flat window base ($1.10/$2.05) at every tier, implying commercial air pays the base; secondary sources say "Ground Residential, Air, Ground Saver" without splitting. The tool defaults to air = all air packages, with a UI footnote; resolve against the official UPS PDF on next refresh.
UPS enterprise (high-volume) demand tiers
Applies only to customers billed >20,000 packages in any week since Oct 2024; once qualified, applies all season (unlike FedEx). Peaking factor = current-week volume ÷ June 1-28, 2025 average weekly baseline. Off-peak = W2 & W4; peak = W3. Note only the 0–105% base row tracks the window — the >105% tiers are flat across windows; Air Commercial pays the flat window base at every tier.
| Peaking factor | Grd Saver / Grd Res, off-peak | same, peak | Air Res, off-peak | Air Res, peak | Air Comm, off-peak | Air Comm, peak |
|---|---|---|---|---|---|---|
| 0–105% | $0.40 | $0.60 | $1.10 | $2.05 | $1.10 | $2.05 |
| >105–125% | $1.60 | $1.60 | $2.75 | $2.75 | $1.10 | $2.05 |
| >125–150% | $2.15 | $2.15 | $3.40 | $3.40 | $1.10 | $2.05 |
| >150–200% | $2.45 | $2.45 | $3.70 | $3.70 | $1.10 | $2.05 |
| >200–300% | $3.10 | $3.10 | $4.25 | $4.25 | $1.10 | $2.05 |
| >300–400% | $5.30 | $5.30 | $6.45 | $6.45 | $1.10 | $2.05 |
| >400% | $7.50 | $7.50 | $8.75 | $8.75 | $1.10 | $2.05 |
4 · FedEx 2025-26 confidence: cross-verified secondary
Confidence: SECONDARY (cross-verified). fedex.com HTML is bot-blocked from the build network, so every cell was cross-verified across 3 agreeing secondary sources (Supply Chain Dive, DCL, Saltbox, with Lojistic and Sifted as additional checks). On refresh, fetch the fedex.com content/dam PDF endpoints instead of the HTML.
| Window | Dates |
|---|---|
| F1 | Sep 29 – Oct 26, 2025 (handling-type fees only) |
| F2 | Oct 27 – Nov 23, 2025 |
| F3 (peak) | Nov 24 – Dec 28, 2025 |
| F4 | Dec 29, 2025 – Jan 18, 2026 |
| Component | Applies to | Residential only | F1 | F2 | F3 | F4 |
|---|---|---|---|---|---|---|
| Demand — Express (Overnight / 2Day / Express Saver) | express | no | $0 | $1.05 | $2.10 | $1.05 |
| Demand — Ground Residential (Ground + Home Delivery) | ground | yes | $0 | $0.40 | $0.65 | $0.40 |
| Demand — Ground Economy (contract-only) | economy | no (inherently residential) | $0 | $2.20 | $3.55 | $2.20 |
| Demand — Additional Handling | all | no | $8.25 | $8.25 | $10.90 | $8.25 |
| Demand — Oversize | all | no | $90.00 | $90.00 | $108.50 | $90.00 |
| Demand — Ground Unauthorized Package | ground | no | $490 | $490 | $545 | $490 |
FedEx enterprise — Residential Delivery Demand Charge
Applies to shippers with >20,000 residential + Ground Economy packages/week; baseline = June 2-29, 2025; reassessed WEEKLY (the key difference vs UPS, whose qualification locks for the season). Charged per package on top of the published demand surcharges, Oct 27, 2025 – Jan 18, 2026. No charge at 0–105%.
| Peaking factor | Ground | Express |
|---|---|---|
| >105–125% | $1.55 | $2.80 |
| >125–150% | $2.20 | $3.45 |
| >150–200% | $2.50 | $3.75 |
| >200–300% | $3.10 | $4.35 |
| >300–400% | $5.25 | $6.50 |
| >400% | $7.50 | $8.75 |
5 · USPS 2025-26 confidence: PRIMARY
Confidence: PRIMARY. The full matrix below was extracted from the official USPS press release PDF — including the 8/19/2025 revision: the commercial Priority Mail / Ground Advantage Zones 1–4 + Parcel Select 26–70 lb cell was cut to $2.25 from the originally announced $3.00. Several blog recaps still show the stale $3.00 — this table has the revised number. Effective midnight Central Oct 5, 2025 through midnight Central Jan 18, 2026 (modeled as inclusive ship dates Oct 5 – Jan 17). One flat window — USPS fees vary by service, zone, and weight, not by week. USPS-stated averages: 5.2% Ground Advantage / 5.6% Priority Mail / 5.6% Priority Mail Express / 5.6% Parcel Select (~$99.5M expected revenue).
Commercial rates (per package)
| Service / zones | 0–3 lb | 4–10 lb | 11–25 lb | 26–70 lb† |
|---|---|---|---|---|
| Priority Mail & Ground Advantage, Zones 1–4 + Parcel Select (all entries) | $0.30 | $0.45 | $0.75 | $2.25 |
| Priority Mail, Zones 5–9 | $0.70 | $1.25 | $2.75 | $6.50 |
| Ground Advantage, Zones 5–9 | $0.35 | $0.75 | $1.25 | $5.50 |
| Priority Mail Express, Zones 1–4 | $1.00 | $1.50 | $3.50 | $8.95 |
| Priority Mail Express, Zones 5–9 | $1.75 | $3.95 | $7.50 | $13.00 |
†26–70 lb cells include Oversized. Cubic mapping: cubic tiers 1–3 → 0–3 lb cell; PM cubic 4–5 and GA cubic 4–9 → 4–10 lb cell; GA cubic 10 → 11–25 lb cell.
| Commercial flat rate | Surcharge |
|---|---|
| Priority Mail large flat-rate box | $1.25 |
| Priority Mail all other flat rate | $0.70 |
| Priority Mail Express flat-rate envelope | $1.75 |
Retail rates (per package)
| Service / zones | 0–3 lb | 4–10 lb | 11–25 lb | 26–70 lb† |
|---|---|---|---|---|
| Priority Mail & Ground Advantage, Zones 1–4 | $0.40 | $0.60 | $0.95 | $3.00 |
| Priority Mail, Zones 5–9 | $0.90 | $1.45 | $3.25 | $7.00 |
| Ground Advantage, Zones 5–9 | $0.50 | $1.00 | $2.00 | $5.75 |
| Priority Mail Express, Zones 1–4 | $1.10 | $2.00 | $3.90 | $9.75 |
| Priority Mail Express, Zones 5–9 | $2.00 | $4.85 | $9.00 | $16.00 |
| Retail flat rate | Surcharge |
|---|---|
| Priority Mail large flat-rate box | $1.45 |
| Priority Mail all other flat rate | $0.90 |
| Priority Mail Express flat-rate envelope | $2.00 |
USPS 2026 stacking caveat: USPS's separate 8% transportation-related time-limited increase (Apr 26, 2026 – Jan 17, 2027) lives in base rates — it is not a peak surcharge, it is excluded from this tool, and the 2026-27 peak surcharge will stack on top of it. USPS announcement.
6 · What the tool refuses to do
- Negotiated / contract rates. Many mid-size contracts waive or discount demand surcharges — the tool computes PUBLISHED list surcharges only.
- Invoice prediction. Excludes base rates, fuel surcharges, DAS/EDAS, year-round residential & handling fees, and DIM weight. The output is the peak-surcharge DELTA only.
- 2026-27 numbers before publication. Until refreshed, the header reads "2025-26 season (most recent published) — 2026-27 schedules expected mid-Aug 2026"; the tool never extrapolates.
- Enterprise tiers without a user-entered peaking factor (we cannot know your baseline); enterprise outputs are labeled "estimate — UPS locks tiers season-long once qualified; FedEx re-rates weekly."
- USPS 2026 caveat: the separate 8% transportation time-limited base-rate increase (Apr 26, 2026 – Jan 17, 2027) is excluded; 2026 peak surcharges will stack on top of it.
7 · Refresh protocol (2026-27 season)
New schedules are expected mid-August to September 2026, based on last cycle's timing: UPS updated its demand PDF Aug 28, 2025; FedEx published domestic demand surcharges July 8, 2025; USPS filed Aug 8, 2025 (effective the first Sunday of October). On refresh:
- UPS: re-fetch the official peak-surcharges page and the assets.ups.com demand PDF (timed out from the build network this pass); fall back to Supply Chain Dive + DCL + Sifted cross-check, requiring 2+ agreeing sources per cell.
- FedEx: the HTML is bot-blocked — fetch the content/dam PDF endpoints instead.
- USPS: watch the about.usps.com newsroom in early August; pull the press-release PDF for the matrix; check for post-filing revisions (the 8/19 revision trap) and the PRC docket; price tables at pe.usps.com.
- Write the new season's data (keeping 2025-26 archived), bump the last-verified date, and update the header copy. If Sept 15 passes without all three carriers published, show per-carrier "pending" states rather than stale-as-current.
Sources
- USPS (PRIMARY — official press release PDF, incl. the 8/19/2025 revision): about.usps.com 2025 holiday price-change release (PDF) · Supply Chain Dive: USPS 2025 holiday increases
- USPS 2026 8% base-rate caveat: about.usps.com transportation-related time-limited price change
- UPS (official, for refresh): assets.ups.com demand surcharges PDF ("August 28, 2025 Update") · ups.com peak-surcharges page
- UPS (cross-verification): Supply Chain Dive: UPS 2025 peak fees · DCL: demand surcharges · 3PL Center: UPS demand surcharges 2025 · Shippo: holiday shipping surcharges (note: carries the stale pre-revision USPS $3.00 cell)
- FedEx (canonical, for refresh): fedex.com demand surcharges · fedex.com content/dam PDF endpoint (naming pattern)
- FedEx (cross-verification): Supply Chain Dive: FedEx 2025 demand surcharges · DCL: demand surcharges · Saltbox: 2025 peak-season surcharges · Lojistic: FedEx 2025-2026 demand surcharges
- Enterprise tier tables (UPS & FedEx): Sifted: FedEx & UPS 2025 demand surcharge guide
Disclaimer: planning estimates from published list schedules only — not your negotiated rates, and not pricing, accounting, or business advice. Carrier schedules can be revised mid-season; verify against your carrier agreement before budgeting.