Ariens RAZOR 21 SELF PROPELLED
Push / Walk-Behind mower · Model 911608 · Residential-duty · Gas
$449 Ariens list price
Manufacturer list price only — it excludes tax, freight, dealer setup and any local discount, and dealers set the final price.
- Mows an acre in 137 min (96 at top speed) How long for your yard? ›
- How these are worked out ›
The Ariens RAZOR 21 SELF PROPELLED is a residential-grade gas walk-behind mower, suited to small-to-mid home lawns, with a 21-inch deck and a 163cc engine. It weighs 77 lb (34.9 kg).
At a glance
Compare similar mowers See how this mower compares with machines of a similar size and purpose.
Chosen by stated rules, not opinion: same class, a deck within 2 in of this one, the same kind of power and a compatible duty class, then the closest power, weight and price, with other makers preferred. Figures are the manufacturers’ published ones; nothing is estimated.
Engine
| Power Source | gas |
|---|---|
| Displacement | 9.9 ci (163 cc) |
| Engine Make | Briggs & Stratton EXi 725 |
Deck
| Cutting Width | 21 in (533 mm) |
|---|---|
| Min Cut Height | 1 in (25 mm) |
| Max Cut Height | 4 in (102 mm) |
| Blades | 1 |
| Blade Tip Speed | 17001 ft/min (5182 m/min) |
| Cut Positions | 7 |
Drive
| Drive System | General Transmission® MA 300 |
|---|---|
| Ground Speed | 3.7 mph |
Dimensions
| Weight | 77 lbs (34.9 kg) |
|---|---|
| Fuel Capacity | 0.3 gal (1.1 L) |
General
| Warranty | 3 yr |
|---|
Similar models
Other push / walk-behind mowers with comparable specs — including other brands — that buyers cross-shop with the RAZOR 21 SELF PROPELLED.
Specs verified against the retailer listing on Jun 7, 2026 — farmandhomesupply.com.
See every mower with a Briggs & Stratton Exi engine ›
Other Ariens Razor models › 3 more in this range: RAZOR 21 DUAL BLADE REFLEX SELF PROPELLED, RAZOR 21 PUSH, RAZOR 21 REFLEX SELF PROPELLED
See all Ariens mowers and specs ›
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Independent reference database. Specs compiled from manufacturer sources and normalized for comparison; verify with the manufacturer or dealer before purchase.
What the specs work out to
Figures MowerFacts computes from Ariens’s own numbers — not published by the manufacturer.
Mowing time
- ¼ acre34 min 24 min
- ½ acre1 h 8 min 48 min
- 1 acre2 h 17 min 1 h 36 min
- 2 acres4 h 33 min 3 h 11 min
About 137 min per acre at 0.44 acres/hour, mowing at 2.6 mph. The second figure is at the published 3.7 mph top speed (0.63 acres/hour) — faster than anyone really mows. About 0.1 acres per tank.
Gate & trailer fit
- 32 in gateFits
- 36 in gateFits
- 48 in gateFits
Needs at least 27 in of clearance (estimated).
Power & run time
- Run time per tank~0.3 h
Mowing times assume 0.44 acres/hour: deck width x 2.6 mph at 80% efficiency, which allows for overlap, turns and trimming. 2.6 mph is 70% of the 3.7 mph top speed Ariens publishes - almost nobody mows flat out. The "at top speed" figure is the same sum at 3.7 mph, shown so you can see it.
Fit uses the deck width plus 6 in for the discharge chute, because Ariens doesn't publish an overall width — measure before buying if a gate is tight.
Run time assumes a typical 1 gal/hour burn at working load; real consumption varies with engine, load and cut.
Ariens RAZOR 21 SELF PROPELLED questions
What size deck is on the Ariens RAZOR 21 SELF PROPELLED?
The Ariens RAZOR 21 SELF PROPELLED has a 21-inch (533 mm) cutting deck with 1 blades.
What engine is in the Ariens RAZOR 21 SELF PROPELLED?
The Ariens RAZOR 21 SELF PROPELLED is powered by a Briggs & Stratton EXi 725, 163 cc. Horsepower is the manufacturer's own rating.
How much does the Ariens RAZOR 21 SELF PROPELLED weigh?
The Ariens RAZOR 21 SELF PROPELLED weighs 77 lb (34.9 kg) as specified by Ariens.
How fast is the Ariens RAZOR 21 SELF PROPELLED?
Top ground speed is 3.7 mph. With its 21-inch deck that works out to about 0.63 acres per hour at 80% efficiency — allowing for overlap, turns and trimming.
How long does the Ariens RAZOR 21 SELF PROPELLED take to mow an acre?
About 1 h 35 min per acre, from its 21-inch deck at 3.7 mph and 80% efficiency — roughly 0.63 acres an hour, so five acres is about 7 h 56 min. Rough or obstacle-heavy ground takes longer; this is deck width times ground speed, not a timed test.
How big is the fuel tank on the Ariens RAZOR 21 SELF PROPELLED?
The Ariens RAZOR 21 SELF PROPELLED holds 0.3 gal (1.1 L) of fuel.
How much does the Ariens RAZOR 21 SELF PROPELLED cost?
Ariens's published list price is $449, checked 23 October 2026. That excludes tax, freight, dealer setup and any local discount — dealers set the final price.
What is the Ariens RAZOR 21 SELF PROPELLED built for?
Residential-duty push / walk-behind mower. Built for home-lawn use.
Source: Ariens (manufacturer) · archived copy